Progress 07/01/11 to 06/30/16
Outputs
Target Audience:The work accomplished is primarily directed to active horticulturists, plant biology researchers, and nutritionists interested in the complexity of signaling systems in plants as they relate to light effects on plant growth. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Jessica Biever, a graduate student in the Plant Biological Sciences (PBS) Graduate Program, did much of the work on UV-B described here. She was awarded her Ph.D. degree in early 2014 and is now a postdoctoral fellow at the University of Missouri, Columbia. Michael Wilson, who did much of the propolis work reported here, was also a graduate student in the PBS Program and he completed his Ph.D. in mid-2014. He is now a Postdoctoral Associate working in the Center for Drug Design of the University of Minnesota Academic Health Center. Dr. Sefanie Dukovic-Schulze, began work on this project as a Research Associate in October, 2015. We expect that she will move to an independent faculty or research position by mid-2017. Redeat Tibebu, the undergraduate, originally from Ethiopia, who worked on this project from 2013-2015, received her B.S. degree from the University of Minnesota in 2015 and has been working for Calyxt, a small biotech company in the Twin Cities area. She is now applying to graduate programs in the plant sciences to prepare herself for a career in agricultural production in developing countries. Molly Kreiser, currently a Ph.D. student in the Plant Biological Sciences graduate program, gave presentations at two major international conferences during 2016. How have the results been disseminated to communities of interest?The propolis work on compound identification was submitted to the journal Phytochemistry earlier in 2016 and has been recommended for publication subject to minor revision. We expected a final decision within a few weeks. Our review article on UV-B and DNA repair was published in the journal Environmental and Experimental Botany. Our work on phytochrome, light, and adventitious rooting was presented at two major international conferences in 2016. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Impacts: Each if the objectives in this project has resulted in a significant change in knowledge, and that new knowledge has been communicate to the appropriate audiences via the scientific literature. The work on propolis under the first objective connects the specialized metabolism of particular resinous plants to the antimicrobial benefits that bees might derive from them and could guide future studies on the therapeutic potential of propolis for bees. The work on glucosinolates in vegetables could have a major impact on dietary recommendations related to cancer prevention. Both of these projects have the potential of leading to a change in action on the part of bee keepers, in the first case, and on the part of nutritionists and the general population with regard to the second. Our work on light and adventitious rooting is still in its early stages. However, these findings have implications for better understanding and potentially improving adventitious rooting in horticulturally important species, which is often a bottleneck to propagation and production. Thus, this work has the potential to lead to a change in action on the part of nurseries and growers of perennial crops. Ambient levels of solar ultraviolet-B light at the earth's surface have been increasing due to depletion of the stratospheric ozone layer. Several studies suggest that current levels of UV-B can affect terrestrial plants, indicating that even small increases in UV-B could have substantial effects on many plant species. One of the primary effects of UV-B on plants is a reduction in photosynthetic productivity, and the general effects are to reduce biomass and decrease the rate of carbon dioxide sequestration. In the long term, our discovery of a novel mechanism by which plants perceive and respond to UV-B radiation could lead to strategies for breeding resistance to UV-B and thus increasing crop yield on a global scale. Our first objective is to develop plant-derived foods or products that benefit human health by pursuing interdisciplinary programs under the auspices of the Healthy Foods, Healthy Lives Institute (HFHL). I have been on the Advisory Board of HFHL since its inception. Another project under this objective, on Novel Antimicrobial Properties of Honeybee Propolis in Human and Animal Health, began as a collaboration in 2007 among Jerry Cohen, Marla Spivak, and Gary Gardner. Propolis is a substance derived from antimicrobial plant resins that honey bees use in the construction of their nests. Propolis use in the hive is an important component of honey bee social immunity and confers a number of positive physiological benefits to bees. The benefits that bees derive from resins are mostly due to their antimicrobial properties, but it is unknown how the diversity of antimicrobial activities among resins might impact bee health. In previous work, we found that resins from different North American Populus spp. differed in their ability to inhibit in vitro growth of the bee bacterial pathogen Paenibacillus larvae, the causative agent of American foulbrood. More recently, using bioassay-guided fractionation against Paenibacillus larvae, 11 structurally related dihydroflavonols were isolated from Fallon, NV, propolis. Six isolated 3-acyl-dihydroflavonols showed activity, in the low micromolar range, against both P. larvae and Ascosphaera apis, the causative agent of chalkbrood disease. The structure-activity relationship between acyl group size and antimicrobial activity differed between the two pathogens, with longer acyl chains increasing activity against P. larvae and shorter acyl chains increasing activity against A. apis. We determined that bees collected the 3-acyl-dihydroflavonols from Populus fremontii, an abundant resinous tree around Fallon, NV, and that some of these compounds can be found in other Populus spp. A third project under this first objective was to maximize the concentration of cancer chemopreventive agents in vegetables, using whole plant studies to determine the environmental conditions that control the biosynthesis of these compounds and field studies to optimize the content of these compounds in the harvested plant material. We have a renewed interest in this project and, in collaboration with V. A. Fritz and colleagues in the University of Minnesota Masonic Cancer Center, are in the process of preparing a major grant proposal on "Chemoprevention by Vegetables," to be submitted to NIH during 2017. Our second objective, in collaboration with J. D. Cohen, is to determine the relationship between the biosynthesis of the plant hormone auxin, primarily indole-3-acetic acid (IAA), and its transport. In 2015 work continued on the kinetics of plant hormone metabolism, auxin transport, and the shade avoidance response (SAR) and the interaction of the SAR with UV-B light. The SAR is a physiological response to a change in light quality that integrates light and hormone signaling, including auxin synthesis and auxin transport. A new collaborative project under this objective was initiated in 2015 on the relationship between the control of adventitious rooting by light and auxin metabolism. During the past year, we found that etiolated Arabdiopsis seedlings exposed to red, white, or blue light for one week produced significantly more adventitious roots than seedlings that were kept in continuous darkness or exposed to far red light only. Phytochrome B (phyB) mutants produced significantly more adventitious roots than wild type (WT) in response to red or white light treatments, but also produced very few adventitious roots under dark conditions. Phytochrome A (phyA) mutants and phyAphyB double mutants produced fewer roots than WT. Auxin (indole-3-acetic acid, IAA) levels were higher in phyB hypocotyls and lower in phyA hypocotyls compared to WT after 3d of light treatment, suggesting elevated auxin is involved in inducing adventitious roots in response to light. Our third objective is to characterize novel ways in which plants respond to visible and ultraviolet (UV) light. UV-B light (280-320 nm) is a component of sunlight and a natural environmental stimulus for plants. It induces photomorphogenic responses but also causes damage to DNA. Hypocotyl growth inhibition by UV-B in etiolated seedlings appears to be the consequence of UV-B-induced photodimer formation and occurs via cell-cycle arrest. The recently described UV-B photoreceptor UVR8 is not required for this hypocotyl growth inhibition in etiolated seedlings. These results suggest that there is a novel pathway specific to UV-B, but independent of UVR8, that influences early Arabidopsis seedling growth and is induced by the direct absorption of UV-B by DNA.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Biever, J.J., and G. Gardner, The Relationship between Multiple UV-B Perception Mechanisms and DNA Repair Pathways in Plants. Environmental and Experimental Botany 124: 8999, 2016.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Kreiser, M., P. Fiesel, J. Cohen, and G. Gardner (2016), PHYA and PHYB regulate adventitious rooting in response to dark-light transitions in Arabidopsis seedlings, Poster Presentation, 5th International Controlled Environment Conference/AusPheno 2016, CSIRO, Canberra, Australia, September 18-24, 2016.
- Type:
Journal Articles
Status:
Under Review
Year Published:
2016
Citation:
Wilson, M.B., A. D. Pawlus, D. Brinkman, G. Gardner, A. D. Hegeman, M. Spivak, and J. D. Cohen, 3-acyl dihydroflavonols from poplar resins collected by honey bees are active against the bee pathogens Paenibacillus larvae and Ascosphaera apis, Phytochemistry, Accepted with minor revision, 2016.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Kreiser, M., J. Cohen, and G. Gardner (2016), PHYA and PHYB regulate adventitious rooting in response to dark-light transitions in Arabidopsis seedlings, Invited Oral Presentation, 22nd International Conference on Plant Growth Substances, University of Toronto, Toronto, Ontario, Canada, June 23, 2016.
|
Progress 10/01/14 to 09/30/15
Outputs
Target Audience:The work accomplished is primarily directed to active horticulturists, plant biology researchers, and nutritionists interested in the complexity of signaling systems in plants as they relate to light effects on plant growth. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Jessica Biever, a graduate student in the Plant Biological Sciences (PBS) Graduate Program, did much of the work on UV-B described here. She was awarded her Ph.D. degree in early 2014 and is now a postdoctoral fellow at the University of Missouri, Columbia. Michael Wilson, who did much of the propolis work reported here, was also a graduate student in the PBS Program and he completed his Ph.D. in mid-2014. He is now a Postdoctoral Associate working in the Center for Drug Design of the University of Minnesota Academic Health Center. Dr. Sefanie Dukovic-Schulze, began work on this project as a Research Associate in October, 2015. How have the results been disseminated to communities of interest?The propolis work on compound identification will be submitted to a peer-reviewed journal in the near future. A provisional patent application on this work was filed in 2015. The UV-B work, also aimed at scientific peers, was presented at the International Symposium on Plant Photobiology in Austin, Texas, in May, 2015, and is the topic of a review article currently under consideration by a peer-reviewed journal. What do you plan to do during the next reporting period to accomplish the goals?Work on this project in 2016 will pursue all three Objectives. Work will continue on the identification of compounds from propolis that may lead to novel therapeutic and preventative strategies for honeybee health. The shade avoidance response will continue to be the model system to study the interaction of light, auxin metabolism, and auxin transport. Significant effort will also be placed on understanding the relationship between light and adventitious rooting and auxin metabolism. Work on the effect of UV-B on the shade avoidance response will continue, and, with the addition of Dr.Stefanie Dukovic-Schulze, an expert on DNA repair, to the project, a good deal of effort will be made to determine the nature of link between UV-B-induced photodimer formation and cell-cycle arrest.
Impacts
What was accomplished under these goals?
Our first objective is to develop plant-derived foods or products that benefit human health by pursuing interdisciplinary programs under the auspices of the Healthy Foods, Healthy Lives Institute (HFHL). I have been on the Advisory Board of HFHL since its inception. Another project under this objective, on Novel Antimicrobial Properties of Honeybee Propolis in Human and Animal Health, began as a collaboration in 2007 among Jerry Cohen, Marla Spivak, and Gary Gardner. Propolis is a substance derived from antimicrobial plant resins that honey bees use in the construction of their nests. Propolis use in the hive is an important component of honey bee social immunity and confers a number of positive physiological benefits to bees. The benefits that bees derive from resins are mostly due to their antimicrobial properties, but it is unknown how the diversity of antimicrobial activities among resins might impact bee health. In previous work, we found that resins from different North American Populus spp. differed in their ability to inhibit in vitro growth of the bee bacterial pathogen Paenibacillus larvae. During the past year our goal was to determine which compounds in propolis are active against bee pathogens, while also determining the botanical sources of these compounds. Using bioassay-guided fractionation against the causative agent of American foulbrood, Paenibacillus larvae, 11 structurally related dihydroflavonols were isolated from Fallon, NV, propolis. Six isolated 3-acyl-dihydroflavonols showed activity, in the low micromolar range, against both P. larvae and Ascosphaera apis, the causative agent of chalkbrood disease. The structure-activity relationship between acyl group size and antimicrobial activity differed between the two pathogens, with longer acyl chains increasing activity against P. larvae and shorter acyl chains increasing activity against A. apis. We determined that bees collected the 3-acyl-dihydroflavonols from Populus fremontii, an abundant resinous tree around Fallon, NV, and that some of these compounds can be found in other Populus spp. This work connects the specialized metabolism of particular resinous plants to the antimicrobial benefits that bees might derive from them and could guide future studies on the therapeutic potential of propolis for bees. Our second objective, in collaboration with J. D. Cohen, is to determine the relationship between the biosynthesis of the plant hormone auxin, primarily indole-3-acetic acid (IAA), and its transport. In 2015 work continued on the kinetics of plant hormone metabolism, auxin transport, and the shade avoidance response (SAR) and the interaction of the SAR with UV-B light. The SAR is a physiological response to a change in light quality that integrates light and hormone signaling, including auxin synthesis and auxin transport. A new collaborative project under this objective was initiated in 2015 on the relationship between the control of adventitious rooting by light and auxin metabolism. Our third objective is to characterize novel ways in which plants respond to visible and ultraviolet (UV) light. UV-B light (280-320 nm) is a component of sunlight and a natural environmental stimulus for plants. It induces photomorphogenic responses but also causes damage to DNA. Arabidopsis mutants of the endonucleases that function in nucleotide excision repair, xpf-3 and uvr1-1, showed hypersensitivity to UV-B (280-320 nm) in terms of hypocotyl growth inhibition. Hypocotyl growth inhibition in etiolated seedlings appears to be the consequence of UV-B-induced photodimer formation. The G2/M-specific cell cycle reporter construct CYCB1;1-GUS accumulates after UV-B irradiation, thus indicating that hypocotyl growth inhibition occurs via cell-cycle arrest. The recently described UV-B photoreceptor UVR8 is not required for this hypocotyl growth inhibition in etiolated seedlings. These results suggest that there is a pathway specific to UV-B, but independent of UVR8, that influences early Arabidopsis seedling growth and is induced by the direct absorption of UV-B by DNA.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Wilson, M., D. Brinkman, M. Spivak, G. Gardner, and J. D. Cohen, Regional variation in composition and antimicrobial activity of U.S. propolis against Paenibacillus larvae and Ascopheara apis, Journal of Invertebrate Pathology, 124: 44-50, 2015.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Gardner G. (2015) Multiple UV-B Perception Mechanisms in Plants, Invited Oral Presentation, International Symposium on Plant Photobiology, University of Texas, Austin, Texas, May 26-31.
- Type:
Journal Articles
Status:
Under Review
Year Published:
2016
Citation:
Biever J.J., and G. Gardner, "The Relationship Between Multiple UV-B Perception Mechanisms and DNA Repair Pathways in Plants," Environmental and Experimental Botany, Under Review, 2015.
|
Progress 10/01/13 to 09/30/14
Outputs
Target Audience: The work accomplished is primarily directed to active horticulturists, plant biology researchers, and nutritionists interested in the complexity of signaling systems in plants as they relate to light effects on plant growth. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Redeat Tibebu, the undergraduate working on the visible light aspects under Objective 3, is a junior college transfer student to the University of Minnesota who is originally from Ethiopia. She will graduate at the end of this academic year and hopes to go to graduate school to prepare herself for a career in agricultural production in developing countries. Jessica Biever, a graduate student in the Plant Biological Sciences (PBS) Graduate Program, did much of the work on UV-B described here. She was awarded her Ph.D. degree in early 2014 and is now a postdoctoral fellow at the University of Missouri, Columbia. Michael Wilson, who did much of the propolis work reported here, was also a graduate student in the PBS Program and he completed his Ph.D. in mid-2014. He is now a Postdoctoral Associate working on the project. How have the results been disseminated to communities of interest? The propolis work, aimed at scientific peers, was published in 2014 in the Journal of Invertebrate Pathology. The UV-B work, also aimed at scientific peers, was published in 2014 in a special issue on plant photobiology in the Journal of Experimental Botany and presented at the annual meeting of the American Society of Plant Biologists. What do you plan to do during the next reporting period to accomplish the goals? Most of the work on this project in 2015 will also focus on Objectives 1 and 3. Work will continue on the identification of compounds from propolis that may lead to novel therapeutic and preventative strategies for honeybee health. Work on UV-B will focus on the interaction of UV-B light with components of plant stress signal transduction and the effect of UV-B on the shade avoidance response.
Impacts
What was accomplished under these goals?
Our first objective is to develop plant-derived foods or products that benefit human health by pursuing interdisciplinary programs under the auspices of the Healthy Foods, Healthy Lives Institute (HFHL). I am on the Advisory Board of HFHL and its Executive Committee. Another project under this objective, on Novel Antimicrobial Properties of Honeybee Propolis in Human and Animal Health, began as a collaboration in 2007 among Jerry Cohen, Marla Spivak, and Gary Gardner. Propolis is a substance derived from antimicrobial plant resins that honey bees use in the construction of their nests. Propolis use in the hive is an important component of honey bee social immunity and confers a number of positive physiological benefits to bees. The benefits that bees derive from resins are mostly due to their antimicrobial properties, but it is unknown how the diversity of antimicrobial activities among resins might impact bee health. In previous work, we found that resins from different North American Populus spp. differed in their ability to inhibit in vitro growth of the bee bacterial pathogen Paenibacillus larvae. The goal of our current work was to characterize the metabolite profiles of propolis from 12 climatically diverse regions across the U.S. using LC-MS-based metabolomic methods and compare antimicrobial activity among those samples against the bee pathogens P. larvae and Ascophaera apis. Samples differed greatly in their ability to inhibit both bacterial and fungal growth in vitro, but propolis from Nevada, Texas, and California displayed high activity against both pathogens. Interestingly, propolis from Georgia, New York, Louisiana, and Minnesota were active against A. apis, but not very active against P. larvae. Metabolomic analysis of regional propolis samples revealed that each sample was compositionally distinct, and LC-FTMS profiles from each sample contained a unique number of shared and exclusive peaks. Propolis from Aspen, CO, Tuscon, AZ, and Raleigh, NC, contained relatively large numbers of exclusive peaks, which may indicate that these samples originated from relatively unique botanical sources. This is the first study to characterize how the diversity of bee preferred resinous plants in the U.S. may affect bee health, and it could guide future studies on the therapeutic potential of propolis for bees. Our second objective, in collaboration with J. D. Cohen, is to determine the relationship between the biosynthesis of the plant hormone auxin, primarily indole-3-acetic acid (IAA), and its transport. Little work was undertaken on this objective in 2014; however. work was begun on the interaction of the shade avoidance response (SAR) with UV-B light. The SAR is a physiological response to a change in light quality that integrates light and hormone signaling, including auxin synthesis and auxin transport. Our third objective is to characterize novel ways in which plants respond to visible and ultraviolet (UV) light. An undergraduate student, Redeat Tibebu, worked in 2013 with Jeff Gillman and Gary Gardner on evaluating various light sources for plant growth for use by home gardeners. She continued this work in 2014 with support from the University of Minnesota Undergraduate Research Opportunities Program. In the summer of 2014, she was a scholar in the McNair Scholars Program, working on the interaction of UV-B light with components of plant stress signal transduction. In the fall semester, 2014, she carried out an independent study project on the effects of green light on plant growth. UV-B light (280-320 nm) is a component of sunlight and a natural environmental stimulus for plants. It induces photomorphogenic responses but also causes damage to DNA. Arabidopsis mutants of the endonucleases that function in nucleotide excision repair, xpf-3 and uvr1-1, showed hypersensitivity to UV-B (280-320 nm) in terms of hypocotyl growth inhibition. A DNA replication inhibitor, hydroxyurea (HU), also inhibited hypocotyl growth in etiolated seedlings, but xpf-3 was not hypersensitive to HU. UV-B irradiation induced accumulation of the G2/M-specific cell cycle reporter construct CYCB1;1-GUS in wild type Arabidopsis seedlings that was consistent with expected accumulation of photodimers and coincided with the time course of hypocotyl growth inhibition after UV-B treatment. Etiolated mutants of UVR8, a recently described UV-B photoreceptor, irradiated with UV-B showed inhibition of hypocotyl growth that was not different from wild type, but they lacked UV-B -specific expression of chalcone synthase (CHS), as expected from previous reports. CHS expression after UV-B irradiation was not different in xpf-3 than in wild type, nor was it altered after HU treatment. These results suggest that hypocotyl growth inhibition by UV-B light in etiolated Arabidopsis seedlings, a photomorphogenic response, is dictated by signals originating from UV-B absorption by DNA that lead to cell-cycle arrest. This process occurs distinct from UVR8 and its signaling pathway responsible for CHS induction.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Biever J. J., D. Brinkman, G. Gardner, UV-B inhibition of hypocotyl growth in etiolated Arabidopsis thaliana seedlings is a consequence of cell-cycle arrest initiated by photodimer accumulation, Journal of Experimental Botany, Special issue on Photobiology, 65: 2949-2961, 2014.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Wilson, M., D. Brinkman, M. Spivak, G. Gardner, and J. D. Cohen, Regional variation in composition and antimicrobial activity of U.S. propolis against Paenibacillus larvae and Ascopheara apis, Journal of Invertebrate Pathology, 124: 44-50, 2015.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Biever J.J., D. Brinkman, and G. Gardner (2014) Ultraviolet-B inhibition of hypocotyl growth in etiolated Arabidopsis seedlings is due to cell cycle arrest initiated by photodimer accumulation. Abs # P02004, Plant Biology 2014, Annual Meeting of the American Society of Plant Biologists, Portland, Oregon, July 12-16, 2014,
|
Progress 01/01/13 to 09/30/13
Outputs
Target Audience: The work accomplished is primarily directed to active horticulturists, plant biology researchers, and nutritionists interested in the complexity of signaling systems in plants as they relate to light effects on plant growth. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Redeat Tibebu, the undergraduate working on the visible light aspects of Objective 3, is a junior college transfer student to the University of Minnesota who is originally from Ethiopia. This was her first research experience, and she will continue on a follow-up project during 2014 with support from the University of Minnesota Undergraduate Research Opportunities Program. Jessica Biever, a graduate student in the Plant Biological Sciences Graduate Program, did much of the work on UV-B described here. She completed her Ph.D. degree at the end of 2013. How have the results been disseminated to communities of interest? The work on evaluation of light sources has been published in the consumer magazine Fine Gardening. The UV-B work, aimed at scientific peers, has been submitted for publication in a special issue on plant photobiology in the Journal of Experimental Botany. What do you plan to do during the next reporting period to accomplish the goals? Most of the work on this project in 2014 will also focus on Objective 3. Work on evaluation of visible light sources will continue with the participation of Redeat Tibebu. Work on UV-B will focus on the interaction of UV-B light with components of plant stress signal transduction.
Impacts
What was accomplished under these goals?
Our first objective is to develop plant-derived foods or products that benefit human health by pursuing interdisciplinary programs under the auspices of the Healthy Foods, Healthy Lives Institute (HFHL). I am on the Advisory Board of HFHL and its Executive Committee. Our second objective, in collaboration with J. D. Cohen, is to determine the relationship between the biosynthesis of the plant hormone auxin, primarily indole-3-acetic acid (IAA), and its transport. After a great deal of progress in 2012, with the completion of the Ph.D. of our joint graduate student Xing Liu, little work was undertaken on this objective in 2013. Our third objective is to characterize novel ways in which plants respond to visible and ultraviolet light. An undergraduate student, Redeat Tibebu, worked in 2013 with Jeff Gillman and Gary Gardner on evaluating various light sources for plant growth for use by home gardeners. She compared a Heliospectra LED lamp with six other light sources on the germination and growth of nine different herbaceous species. This work led to an article in the consumer publication Fine Gardening. Ultraviolet (UV) radiation is an important constituent of sunlight that determines plant morphology and growth. It induces photomorphogenic responses but also causes damage to DNA. Arabidopsis mutants of the endonucleases that function in nucleotide excision repair, xpf-3 and uvr1-1, showed hypersensitivity to UV-B (280-320 nm) in terms of hypocotyl growth inhibition. SOG1 is a transcription factor that functions in the DNA damage signaling response after gamma irradiation. xpf mutants that carry the sog1-1 mutation showed hypocotyl growth inhibition after UV-B irradiation similar to wild type. A DNA replication inhibitor, hydroxyurea (HU), also inhibited hypocotyl growth in etiolated seedlings, but xpf-3 was not hypersensitive to HU. UV-B irradiation induced accumulation of the G2/M-specific cell cycle reporter construct CYCB1;1-GUS in wild type Arabidopsis seedlings that was consistent with expected accumulation of photodimers and coincided with the time course of hypocotyl growth inhibition after UV-B treatment. Etiolated mutants of UVR8, a recently described UV-B photoreceptor, irradiated with UV-B showed inhibition of hypocotyl growth that was not different from wild type, but they lacked UV-B -specific expression of chalcone synthase (CHS), as expected from previous reports. CHS expression after UV-B irradiation was not different in xpf-3 than in wild type, nor was it altered after HU treatment. These results suggest that hypocotyl growth inhibition by UV-B light in etiolated Arabidopsis seedlings, a photomorphogenic response, is dictated by signals originating from UV-B absorption by DNA that lead to cell-cycle arrest. This process occurs distinct from UVR8 and its signaling pathway responsible for CHS induction.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Liu, X., J. Wu, G. Clark, S. Lundy, M. Lim, D. Arnold, J. Chan, W. Tang, G. K. Muday, G. Gardner, and S. J. Roux, Role for apyrases in polar auxin transport in Arabidopsis, Plant Physiol. 160: 19851995, December, 2012.
- Type:
Other
Status:
Published
Year Published:
2013
Citation:
Gillman, J., G. Gardner, R. Tibebu, and D. Brinkman, Get the right light, Fine Gardening 155: 48-51, February, 2014 (Published December, 2013).
- Type:
Journal Articles
Status:
Under Review
Year Published:
2014
Citation:
Biever J. J., D. Brinkman, G. Gardner, UV-B inhibition of hypocotyl growth in etiolated Arabidopsis thaliana seedlings is a consequence of cell-cycle arrest initiated by photodimer accumulation, Submitted to Journal of Experimental Botany, Special issue on Photobiology, September, 2013.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Biever J., D. Brinkman, and G. Gardner (2013) Absorption of UV-B light by DNA induces photomorphogenic responses in etiolated Arabidopsis seedlings, Poster Presentation #CU5, International Symposium on Plant Photobiology University of Edinburgh, Edinburgh, Scotland, United Kingdom, June 3-6.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Biever J., D. Brinkman, and G. Gardner (2013) DNA Damage Induces UV-B Photomorphogenic Responses in Etiolated Arabidopsis Seedlings. Abs # P02001, Plant Biology 2013, Annual Meeting of the American Society of Plant Biologists, Providence, Rhode Island. July 20-24, 2013,
http://precis.preciscentral.com/utils/ip/ShowSummary.asp?AbstractId=252&Presenter=
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: Our first objective is to develop plant-derived foods or products that benefit human health by pursuing interdisciplinary programs under the auspices of the Healthy Foods, Healthy Lives Institute (HFHL). I am on the Advisory Board of HFHL and its Executive Committee. Our second objective is to determine the relationship between the biosynthesis of the plant hormone auxin, primarily indole-3-acetic acid (IAA), and its transport. Using radioisotope labeling and stable-isotope dilution, we found that in etiolated tomato seedlings, a brief light exposure increased both IAA biosynthesis in the upper tissue sections and polar IAA transport in hypocotyls in a phytochrome-dependent manner, leading to unchanged free IAA levels in the top section and increased free IAA levels in the lower hypocotyl regions. In addition, using stable-isotope labeling and stable-isotope dilution, we found that the transport of indole-3-butyric acid (IBA), another endogenous auxin, was much lower than IAA and that its transport mechanism was distinct from IAA transport. We also found that a small amount of IBA metabolic products, such as ester-linked IBA and IAA, was transported, while the majority of transported IAA remained as free IAA, suggesting that the polar transport of IAA could directly change the level of IAA while the transport of IBA could be an additional means to regulate IAA. Our third objective is to characterize novel ways in which plants respond to visible and ultraviolet light. When etiolated Arabidopsis seedlings are irradiated with UV-B light (280-320 nm), hypocotyl elongation is inhibited and expression of genes such as chalcone synthase (CHS), the first committed step in flavonoid biosynthesis, is induced. UVR8 was recently proposed to be the plant photoreceptor for UV-B light (280-320 nm). uvr8 mutants are more sensitive to UV-B than wild type and also lack the UV-induction of CHS. UVR8 is not required for UV-B specific inhibition of hypocotyl elongation, but is necessary for UV-B specific CHS induction. The nucleotide excision repair mutant (NER), xpf-3, shows enhanced inhibition of hypocotyl elongation even after irradiation with very low fluences of UV-B that do not induce a response in wild type, suggesting that DNA damage may be a cause of reduced hypocotyl elongation. Hydroxyurea (HU) blocks DNA replication and is used to mimic the effects that increased DNA damage may have after UV-B. When HU was applied to wild type Arabidopsis, it induced a similar hypocotyl elongation response as UV-B. UV-B specific CHS induction is not different from wild type in xpf-3, nor is it increased after the addition of 1 mM HU in wild type, which indicates that an accumulation of DNA damage does not interfere with normal CHS induction after UV-B, but also that DNA damage does not simply induce a standard stress response in etiolated seedlings after UV-B. We have also shown, as reported by others, that the expression of the gene UDPgtfp by UV-B is independent of UVR8. Taken together, these observations indicate that UVR8 cannot be the only UV-B photoreceptor in Arabidopsis. PARTICIPANTS: Dr. Gary Gardner, Professor, Department of Horticultural Science, University of Minnesota, PI. Objective 1: Dr. Mindy S. Kurzer, Professor, Department of Food Science and Nutrition, Director, Healthy Foods, Healthy Lives Institute, University of Minnesota; Objective 2: Dr. Jerry D. Cohen, Professor, Department of Horticultural Science, University of Minnesota, Co-PI; Dr. Xing Liu, Research Assistant, Plant Biological Sciences Graduate Program, University of Minnesota (now at California Institute of Technology, Pasadena, California); Dr. Stanley J. Roux, Professor, Department of Molecular, Cell and Developmental Biology, University of Texas, Austin, Texas. Objective 3: Mr. Doug Brinkman, Junior Scientist, Department of Horticultural Science, University of Minnesota; Ms. Jessica Biever, Research Assistant, Plant Biological Sciences Graduate Program, University of Minnesota. TARGET AUDIENCES: The work accomplished is primarily directed to active horticulturists, plant biology researchers, and nutritionists interested in the complexity of signaling systems in plants as they relate to light effects on plant growth. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The results of this research could lead to a new market concept of a branded product line of produce certified to be high in disease-preventing compounds. The value-added agricultural opportunity will benefit consumers, the processing industry, and farmers. An understanding of UV-B photoperception in plants could lead to strategies to increase photosynthetic productivity, to regulate plant growth and development in a positive way, and to manipulate metabolic pathways in phenolic biosynthesis for the benefit of both plants and humans.
Publications
- Liu, X., L. Barkawi, G. Gardner, and J. D. Cohen, Transport of Indole-3-Butyric Acid and Indole-3-Acetic Acid in Arabidopsis Hypocotyls Using Stable Isotope Labeling, Plant Physiol. 158: 1988-2000, 2012.
- Liu, X., A. D. Hegeman, G. Gardner, and J. D. Cohen, Protocol: High-throughput and Quantitative Assays of Auxin and Auxin Precursors from Minute Tissue Samples, Plant Methods. 8: 31, 2012.
- Liu, X., J. Wu, G. Clark, S. Lundy, M. Lim, D. Arnold, J. Chan, W. Tang, G. K. Muday, G. Gardner, and S. J. Roux, Role for apyrases in polar auxin transport in Arabidopsis, Plant Physiol. pp.112.202887; First Published on October 15, 2012.
- Biever J., D. Brinkman, and G. Gardner (2012) Is UVR8 the UV-B Photoreceptor in Etiolated Arabidopsis Seedlings Abstract # P11013 (Poster), Plant Biology 2012, Annual Meeting of the American Society of Plant Biologists, Austin, Texas, July 20 - 24, 2011. http://precis.preciscentral.com/utils/ip/ShowSummary.aspAbstractId=1 856&Presenter=
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: Our first objective is to develop plant-derived foods or products that benefit human health by pursuing interdisciplinary programs under the auspices of the Healthy Foods, Healthy Lives Institute (HFHL). I am on the Advisory Board of HFHL and its Executive Committee. Our second objective is to determine the relationship between the biosynthesis of the plant hormone auxin and its transport. We found that light increased polar auxin transport (PAT) in dark-grown Arabidopsis and tomato hypocotyls. In tomato this increase was induced by low-fluence red (R) or blue (B) light followed by one day of darkness. It was reduced in phyA, phyB1, and phyB2 tomato mutants and was reversed by far-red light applied immediately after the R or B exposure, suggesting that phytochrome is involved in this response. We further found that the free indole-3-acetic acid (IAA) level in hypocotyl regions below the hook was increased by R, while the level of conjugated IAA was unchanged. Analysis of IAA synthesized from [13C]indole or [13C]tryptophan (Trp) revealed that both Trp-dependent and Trp-independent IAA biosynthesis were increased by low-fluence R in the top section, and the Trp-independent pathway appears to be the primary route for IAA biosynthesis after R exposure. IAA biosynthesis in lower tissues was not affected by R, suggesting that the increase of free IAA in this region was due to increased transport of IAA from above. Polar transport of the natural auxins indole-3-butyric acid (IBA) and IAA has been described using radioactive tracers. Because radioactive assays alone cannot distinguish IBA from its metabolites, the detected transport from applied [3H]IBA may have resulted from the transport of IBA metabolites, including IAA. To test this hypothesis, we used a mass spectrometry (MS)-based method to quantify the transport of IBA in Arabidopsis hypocotyls by following the movement of stable-labeled [13C]IBA and the [13C]IAA derived from [13C]IBA. Our results demonstrate that polar transport of IBA is much lower than IAA in Arabidopsis hypocotyls, and the transport mechanism is distinct from IAA transport. Our third objective is to characterize novel ways in which plants respond to visible and ultraviolet light, specifically whether UV-B-induced DNA damage itself can lead to signal transduction and expression of genes seemingly unrelated to DNA repair, i. e., whether DNA is the photoreceptor. When etiolated Arabidopsis thaliana seedlings are irradiated with UV-B light (280-320 nm), hypocotyl elongation is inhibited and expression of genes such as chalcone synthase (CHS), the first committed step in flavonoid biosynthesis, is induced. The DNA repair mutants uvr1-1 and xpf-3 are hypersensitive to UV-B, and, after UV irradiation, hypocotyl elongation is drastically inhibited, especially at lower fluences, compared to their respective wild type backgrounds. The accumulation and persistence of unrepaired UV-B specific photodimers can lead to double strand breaks or blocked replication forks that cause cell cycle arrest which may, ultimately, manifest in enhanced inhibition of hypocotyl elongation seen in the repair mutants. PARTICIPANTS: Dr. Gary Gardner, Professor, Department of Horticultural Science, University of Minnesota, PI. Objective 1: Dr. Mindy S. Kurzer, Professor, Department of Food Science and Nutrition, Director, Healthy Foods, Healthy Lives Institute, University of Minnesota; Dr. Vincent A. Fritz, Professor, Department of Horticultural Science, Southern Research and Outreach Center, University of Minnesota. Objective 2: Dr. Jerry D. Cohen, Professor, Department of Horticultural Science, University of Minnesota, Co-PI; Ms. Xing Liu, Research Assistant, Plant Biological Sciences Graduate Program, University of Minnesota; Dr. Stanley J. Roux, Professor, Department of Molecular, Cell and Developmental Biology, University of Texas, Austin, Texas. Objective 3: Mr. Doug Brinkman, Junior Scientist, Department of Horticultural Science, University of Minnesota; Ms. Jessica Biever, Research Assistant, Plant Biological Sciences Graduate Program, University of Minnesota. TARGET AUDIENCES: The work accomplished is primarily directed to active horticulturists, plant biology researchers, and nutritionists interested in the complexity of signaling systems in plants as they relate to light effects on plant growth. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The results of this research could lead to a new market concept of a branded product line of produce certified to be high in disease-preventing compounds. The value-added agricultural opportunity will benefit consumers, the processing industry, and farmers. An understanding of UV-B photoperception in plants could lead to strategies to increase photosynthetic productivity, to regulate plant growth and development in a positive way, and to manipulate metabolic pathways in phenolic biosynthesis for the benefit of both plants and humans.
Publications
- Liu, X., J. D. Cohen, and G. Gardner, Low-Fluence Red Light Increases the Transport and Biosynthesis of Auxin, Plant Physiol. 157: 891-904, 2011.
- Liu, X., G. Gardner, and J. D. Cohen, Evaluation of the transport of indole-3-butyric acid in Arabidopsis thaliana hypocotyls by stable isotope labeling and gas chromatography-selected reaction monitoring-mass spectrometry, Plant Physiol., Submitted, November, 2011.
- Justen, V. L., J. D. Cohen, G. Gardner, and V. A. Fritz, Seasonal Variation in Glucosinolate Accumulation in Turnip Cultivars Grown with Colored Plastic Mulches, HortScience 46(12): 1-7. 2011.
- Biever J., D. Brinkman, and G. Gardner (2011) Are photomorphogenic responses to UV-B the consequences of DNA damage? Abstract # M0602 (Invited Minisymposium Talk), P11005 (Poster), Plant Biology 2011, Annual Meeting of the American Society of Plant Biologists, Minneapolis, Minnesota, August 6-10, 2011. http://abstracts.aspb.org/pb2011/public/M06/M0602.html
- Clark, G., J Wu, X. Liu, T. Pham. A. Cervantes, J. D. Cohen, G. Gardner. and S. J. Roux (2011) Role for ectoapyrases in gravitropic responses and polar auxin transport in Arabidopsis, Abstract # P20041 (Poster), Plant Biology 2011, Annual Meeting of the American Society of Plant Biologists, Minneapolis, Minnesota, August 6-10, 2011. http://abstracts.aspb.org/pb2011/public/P20/P20041.html
- Liu, X., G. Gardner. and J. D. Cohen (2011) Low fluence red light exposure alters polar transport and biosynthesis of auxin in etiolated tomato hypocotyls, Abstract # M1302 (Invited Minisymposium Talk), P16013 (Poster), Plant Biology 2011, Annual Meeting of the American Society of Plant Biologists, Minneapolis, Minnesota, August 6-10, 2011. http://abstracts.aspb.org/pb2011/public/M13/M1302.html
- Liu, X., G. Gardner. and J. Cohen (2011) Evaluation of IBA Transport in Arabidopsis Hypocotyls by Stable Isotope Labeling and GC-MS/MS, Abstract # 21386, International Conference on Arabidopsis Research, Madison, Wisconsin, June 22 - 25, 2011. http://www.union.wisc.edu/arabidopsis/view_abstract.asp
- Biever J., D. Brinkman, and G. Gardner, Are photomorphogenic responses to UV-B the consequences of DNA damage? International Symposium on Plant Photobiology, Beijing, China, July 2-6, 2011.
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Our first objective is to develop plant-derived foods or products that benefit human health, in part, by pursuing interdisciplinary programs under the auspices of the Center for Plants and Human Health. This work is now part of the Healthy Foods, Healthy Lives Institute (HFHL). I am on the Advisory Board of HFHL and its Executive Committee. During 2010 I played a major role in planning the 2nd annual HFHL symposium, "Plant Foods for Human Health," held Sept. 30 - Oct. 1. Our second objective is to determine the relationship between the biosynthesis of the plant hormone auxin and its transport. We have established a polar auxin transport (PAT) assay system in etiolated Arabidopsis and tomato hypocotyls which provides highly specific basipetal auxin transport measurements. PAT increases in etiolated tomato hypocotyls by 30-60% after 1 d cool white fluorescent light (W), 1 h W followed by 1 d darkness (D), or 1 h blue (B) or red (R) light followed by 1 d D. This promotion in PAT was very sensitive to low levels of B and R: 100 umol/sq m (20 s duration) of B or R followed by 1 d D led to a significant increase in PAT, and the promotion was more sensitive to R than B. This increase was partially reduced in phytochrome A and phytochrome B1 tomato mutants, but not altered in a cryptochrome 1 (cry1) mutant. In addition, 100 umol/sq m of far red partially reversed the PAT promotion induced by R or B, further suggesting the response was mediated by phytochromes. In contrast, the content of free IAA 1 d after the same light treatment was not changed compared with the dark control, but a transient increase in IAA content was found within 5 h after the 1 h W treatment. In Arabidopsis 2-d continuous W, R, or B doubles the PAT in dark-grown hypocotyls. A short treatment of either W or B does not reproduce that effect as it does in tomato. The promotion of auxin transport by 2 d W occurs as normal in a phototropin 1 mutant but is greatly reduced in a phototropin 2 mutant. Our third objective is to characterize novel ways in which plants respond to visible and ultraviolet light and identify methods by which managing light quality can help to manage crop growth. One goal of this objective is to determine whether UV-B-induced DNA damage itself can lead to signal transduction and expression of genes seemingly unrelated to DNA repair, i. e., whether DNA is the photoreceptor. Etiolated Arabidopsis seedlings, when irradiated with UV-B light (280-320 nm), show a fluence-dependent inhibition of hypocotyl elongation. The mutants uvr1-1 and xpf are hypersensitive to UV-B, even at very low fluences. Both of these mutants are in genes encoding endonucleases involved in nucleotide excision repair. An as yet uncharacterized mutant, 15-49-7-2B4, is less sensitive to UV-B than its cry1cry2 background. UV-B irradiation increases gene expression of chalcone synthase (CHS) and a number of other genes. Therefore, expression of CHS was determined using quantitative real-time PCR in wild type Arabidopsis, cry1cry2, and the Arabidopsis mutants noted above to compare any alteration in CHS induction with UV-B sensitivity. PARTICIPANTS: Dr. Gary Gardner, Professor, Department of Horticultural Science, University of Minnesota, PI. Objective 1: Dr. Mindy S. Kurzer, Professor, Department of Food Science and Nutrition, Director, Healthy Foods, Healthy Lives Institute, University of Minnesota. Objective 2: Dr. Jerry D. Cohen, Professor, Department of Horticultural Science, University of Minnesota, Co-PI; Dr. Lana S. Barkawi, Research Associate, Department of Horticultural Science, University of Minnesota; Ms. Xing Liu, Research Assistant, Plant Biological Sciences Graduate Program, University of Minnesota; Dr. Stanley J. Roux, Professor, Department of Molecular, Cell and Developmental Biology, University of Texas, Austin, Texas. Objective 3: Mr. Doug Brinkman, Junior Scientist, Department of Horticultural Science, University of Minnesota; Ms. Jessica Biever, Research Assistant, Plant Biological Sciences Graduate Program, University of Minnesota. TARGET AUDIENCES: The work accomplished is primarily directed to active horticulturists, plant biology researchers, and nutritionists interested in the complexity of signaling systems in plants as they relate to light effects on plant growth. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The results of this research could lead to a new market concept of a branded product line of produce certified to be high in disease-preventing compounds. The value-added agricultural opportunity will benefit consumers, the processing industry, and farmers. An understanding of UV-B photoperception in plants could lead to strategies to increase photosynthetic productivity, to regulate plant growth and development in a positive way, and to manipulate metabolic pathways in phenolic biosynthesis for the benefit of both plants and humans.
Publications
- Liu, X., J. D. Cohen, and G. Gardner, 2010, Polar Auxin Transport is Increased by Light in Tomato and Arabidopsis Hypocotyls, Invited Oral Presentation, 20th International Conference on Plant Growth Substances, Tarragona, Spain, June 28-July 2.
- Biever J., G. Gardner, and D. Brinkman, 2010, UV-B Induced Gene Expression in Etiolated Seedlings of Arabidopsis thaliana with Altered UV-B Sensitivity, Abs # P08112, Plant Biology 2010, Annual Meeting of the American Society of Plant Biologists, Montreal, Quebec, Canada, July 31-August 4. http://abstracts.aspb.org/pb2010/public/P08/P08112.html
- Liu, X., J. D. Cohen, and G. Gardner, 2010, Polar Auxin Transport is Increased by Light in Tomato and Arabidopsis Hypocotyls, Abstract #P10013, Plant Biology 2010, Annual Meeting of the American Society of Plant Biologists, Montreal, Quebec, Canada, July 31-August 4. http://abstracts.aspb.org/pb2010/public/P10/P10013.html
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Our first objective is to develop plant-derived foods or products that benefit human health, in part, by pursuing interdisciplinary programs under the auspices of the Center for Plants and Human Health. This work has now been folded into the mission of the new Healthy Foods, Healthy Lives Institute (HFHL). I serve as a member of the Advisory Board of HFHL and its Executive Committee. During 2009 I played a major role in planning the first annual HFHL symposium, "Critical Issues in Research and Public Policy," held on Sept. 21, and I moderated a session on Organic Agriculture. Our second objective, in collaboration with J. D. Cohen, is to determine the relationship between the biosynthesis of the plant hormone auxin and its polar transport. Much of our progress has been on the relationship between light and auxin transport in hypocotyls of tomato and Arabidopsis. Transferring etiolated tomato hypocotyls to cool white fluorescent light for 1 d increased basipetal auxin transport by about 50%. 1h of white light followed by 1d of darkness has the same effect as 1d of continuous white light, and blue light can substitute for white. This promotion of auxin transport is extremely sensitive to the amount of blue light; as little as 100 umol/sq. m of blue light (a duration of 5s), followed by 1 d darkness causes a significant promotion in polar auxin transport. 1 h of blue light increases polar auxin transport to the same extent in the cryptochrome 1 tomato mutant as in its wild type background. In Arabidopsis 2 d of continuous cool white fluorescent light dramatically increases polar auxin transport. A short treatment of either white or blue light does not reproduce that effect as it does in tomato. The promotion of auxin transport by 2 d of white light occurs as normal in a phototropin 1 mutant but is greatly reduced in a phot2 mutant. Thus, data from both tomato and Arabidopsis suggest that absorption of light by Phot2 may be the first step in the promotion of polar auxin transport by light. Our third objective is to characterize novel ways in which plants respond to visible and ultraviolet light and identify methods by which managing light quality can help to manage crop growth. Our work on the response of Arabidopsis hypocotyls to UV-B light has now been published (see below). One goal of this objective is to determine whether UV-B-induced DNA damage itself can lead to signal transduction and expression of genes seemingly unrelated to DNA repair, i. e., whether DNA is the photoreceptor. The allelic repair mutants uvr1 and uvh3 show greatly enhanced sensitivity to the lowest doses of light tested; whereas, the photolyase mutant uvr2 and the nucleotide excision repair mutant uvh1 show a response similar to the wild type. These data suggest that even at low fluence rates, direct damage to DNA may be one component of the response to UV-B. We are currently directly measuring DNA photoproducts after in vivo irradiation of etiolated plants with the same UV-B fluences that result in inhibition of hypocotyl elongation, and we are just initiating experiments to determine expression of genes in response to UV-B in the repair mutants we have identified. PARTICIPANTS: Dr. Gary Gardner, Professor, Department of Horticultural Science, University of Minnesota, PI. Objective 1: Dr. Mindy S. Kurzer, Professor, Department of Food Science and Nutrition, Director, Healthy Foods, Healthy Lives Institute, University of Minnesota Objective 2: Dr. Jerry D. Cohen, Professor, Department of Horticultural Science, University of Minnesota, Co-PI. Dr. Lana S. Barkawi, Research Associate, Department of Horticultural Science, University of Minnesota Ms. Xing Liu, Research Assistant, Plant Biological Sciences Graduate Program, University of Minnesota Objective 3: Mr. Doug Brinkman, Junior Scientist, Department of Horticultural Science, University of Minnesota Ms. Jessica Biever, Research Assistant, Plant Biological Sciences Graduate Program, University of Minnesota Dr. Cynthia Weinig, Associate Professor of Botany and Molecular Biology, University of Wyoming, Laramie, Wyoming Ms. Jennifer Dechaine, Research Assistant, Plant Biological Sciences Graduate Program, University of Minnesota TARGET AUDIENCES: The work accomplished is primarily directed to active horticulturists, plant biology researchers, and nutritionists interested in the complexity of signaling systems in plants as they relate to light effects on plant growth. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The results of this research could lead to a new market concept of a branded product line of produce certified to be high in disease-preventing compounds. The value-added agricultural opportunity will benefit consumers, the processing industry, and farmers. An understanding of UV-B photoperception in plants could lead to strategies to increase photosynthetic productivity, to regulate plant growth and development in a positive way, and to manipulate metabolic pathways in phenolic biosynthesis for the benefit of both plants and humans.
Publications
- Dechaine, J. M., G. Gardner, and C. Weinig, Phytochromes differentially regulate seed germination responses to light quality and temperature cues during seed maturation, Plant, Cell & Environment, 32: 1297-1309, 2009. DOI: 10.1111/j.1365-3040.2009.01998.x, Published Online 15 May 2009.
- Gardner, G., C. Lin, E. M. Tobin, H. Loehrer, and D. Brinkman, Photobiological Properties of the Inhibition of Etiolated Arabidopsis Seedling Growth by Ultraviolet-B Irradiation, Plant, Cell & Environment, 32: 1573-1583, 2009. DOI: 10.1111/j.1365-3040.2009.02021.x, Published Online 17 July 2009.
- Gardner, G., Review of Plant Hormone Signaling, Ed. By Peter Hedden and Stephen G. Thomas, HortScience 44: 222, 2009.
- Liu, X., L. S. Barkawi, J. D. Cohen, and G. Gardner, Environmental Regulation of Auxin Metabolism, Poster Abstract #215, Keystone Symposium on Plant Sensing, Response and Adaptation to the Environment, Big Sky, Montana, January 1-16, 2009.
- Biever J., G. Gardner, and D. Brinkman, The role of DNA damage and repair in the UV-B response of etiolated Arabidopsis thaliana, Abs # P44017, Joint Annual Meeting of the American Society of Plant Biologists and the Phycological Society of America, Honolulu, Hawaii July 18-22, 2009, http://abstracts.aspb.org/pb2009/public/P44/P44017.html
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: The first objective of this project is to develop plant-derived foods or products that benefit human health by determining the effect of light and temperature on the content of cancer-preventing compounds in vegetables. During the past year, our main work on this objective was to co-edit the proceedings of Symposium S-03, Plants as Food and Medicine: The Utilization and Development of Horticultural Plants for Human Health, held at the 27th International Horticultural Congress, Seoul, Korea, August 13-19, 2006. This was published as a volume of Acta Horticulturae in 2008. Our second objective, in collaboration with J. D. Cohen, is to determine the relationship between the biosynthesis of the plant hormone auxin and its polar transport. We have found that the free IAA level and IAA biosynthesis in the apical tip of etiolated maize coleoptiles were elevated after mechanical wounding. We have also found that IAA transport capacity drops steadily over time after wounding. Our results indicate that the cells at the cut end of the section do not transport IAA basipetally, perhaps as a mechanism to elevate the levels of IAA at the wound site. Furthermore, we have also found in a preliminary study that a brief exposure to ambient fluorescent light decreases free IAA levels in maize coleoptile tips. We will identify the metabolic origin of the free IAA reduction following light exposure by analyzing the isotopic enrichment of IAA derived from labeled precursors and conjugates as well as determine changes in levels of these compounds. Our third objective is to characterize novel ways in which plants respond to visible and ultraviolet light and identify methods by which managing light quality can help to manage crop growth. In collaboration with E. Tobin and C. Lin at UCLA we have continued our search for an ultraviolet-B (UV-B, 280-320 nm) photoreceptor in plants. We have carried out fluence response curves and, by the use of filtering plastics, demonstrated that the response is specific to UV-B light and not UV-A. The response shows reciprocity between duration and intensity, at least over a limited range, and thus depends only on photon fluence and not on photon flux. The action spectrum for this response indicates a peak of maximum effectiveness at 290 nm, and response spectra at different fluences indicate that the most effective wavelength at 30,000 umol/ sq m is 290 nm; whereas, 300 nm light is the most effective at 100,000 umol/sq m. This response occurs in mutant seedlings deficient in cryptochrome, phytochrome, or phototropin, suggesting that none of the known photoreceptors is the major UV-B photoreceptor. Some null mutants in DNA repair enzymes show hypersensitivity to UV-B, suggesting that even at low fluence rates, direct damage to DNA may be a component of the response to UV-B. We have screened nearly 38,000 T-DNA insertional mutants for plants that are altered in this response and planted 1451 of those to generate seed. Thus far, we have collected seed from 897 lines and carried out fluence response curves on 154 of those. To date, 21 lines have demonstrated reduced sensitivity to UV. Characterization of these lines continues. PARTICIPANTS: Dr. Gary Gardner, Professor, Department of Horticultural Science, University of Minnesota, PI. Objective 2: Dr. Jerry D. Cohen, Professor, Department of Horticultural Science, University of Minnesota, Co-PI. Dr. Lana S. Barkawi, Research Associate, Department of Horticultural Science, University of Minnesota Ms. Xing Liu, Research Assistant, Plant Biological Sciences Graduate Program, University of Minnesota Objective 3: Mr. Doug Brinkman, Junior Scientist, Department of Horticultural Science, University of Minnesota Ms. Jessica Biever, Research Assistant, Plant Biological Sciences Graduate Program, University of Minnesota Dr. Cynthia Weinig, Associate Professor of Botany and Molecular Biology, University of Wyoming, Laramie, Wyoming Ms. Jennifer Dechaine, Research Assistant, Plant Biological Sciences Graduate Program, University of Minnesota TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The results of this research could lead to a new market concept of a branded product line of produce certified to be high in disease-preventing compounds. The value-added agricultural opportunity will benefit consumers, the processing industry, and farmers. An understanding of UV-B photoperception in plants could lead to strategies to increase photosynthetic productivity, to regulate plant growth and development in a positive way, and to manipulate metabolic pathways in phenolic biosynthesis for the benefit of both plants and humans.
Publications
- Gardner, G., and Craker, L. E., Eds. 2008. Plants as Food and Medicine: The Utilization and Development of Horticultural Plants for Human Health, Proceedings, XXVII International Horticultural Congress (IHC2006), Acta Horticulturae 765, Int. Soc. Hort. Sci., Leuven, Belgium.
- Gardner, G., Lin, C., Tobin, E.M., Loehrer, H., and Brinkman, D. 2008. The Effect of UV-B Irradiation on the Growth of Etiolated Arabidopsis Seedlings. 2008 International Plant Photobiology Meeting & 25th Annual Missouri Plant Biology Symposium, University of Missouri-Columbia, May 28-31.
- Dechaine, J. M., Gardner, G., and Weinig, C. 2008. Phytochromes differentially mediate seed germination responses to a combination of maternal temperature and light environments. 2008 International Plant Photobiology Meeting & 25th Annual Missouri Plant Biology Symposium, University of Missouri-Columbia, May 28-31.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: The first objective of this project is to develop plant-derived foods or products that benefit human health by determining the effect of light and temperature on the content of cancer-preventing compounds in vegetables. During the past year, our main work on this objective was to co-edit the proceedings of Symposium S-03, Plants as Food and Medicine: The Utilization and Development of Horticultural Plants for Human Health, held at the 27th International Horticultural Congress, Seoul, Korea, August 13-19, 2006. This was published as a volume of Acta Horticulturae in 2007 (see Publications). Our second objective is to determine the relationship between the biosynthesis of the plant hormone auxin and its specific polar transport. We have found that there is de novo synthesis of IAA in etiolated maize seedlings, that free IAA in the etiolated maize coleoptile tip increases with time after wounding, and that the increase of free IAA levels in wounded etiolated maize seedlings is
due, at least in part, to biosynthesis. In addition, we have recently found that stable isotope-labeled indole-3-butyric acid is largely converted to IAA as it enters or moves through the auxin transport system in maize coleoptiles. Our third objective is to characterize novel ways in which plants respond to visible and ultraviolet light and identify methods by which managing light quality can help to manage crop growth. We have continued our search for an ultraviolet-B (UV-B, 280-320 nm) photoreceptor in plants. We seek to understand the effects of UV-B irradiation by 1) characterizing the growth inhibition of etiolated Arabidopsis seedlings by low fluence UV light; 2) characterizing the response in known mutants of photoreceptor genes and other genes involved in UV signal transduction and DNA repair; and 3) attempting to identify and characterize mutants of Arabidopsis that demonstrate a decreased sensitivity to UV-B. We have carried out fluence response curves, and, by the use of
filtering plastics, demonstrated that the response is specific to UV-B light and not UV-A. The response shows reciprocity between duration and intensity, at least over a limited range, and thus depends only on photon fluence and not on photon flux. The action spectrum for this response indicates a peak of maximum effectiveness at 290 nm. This response occurs in mutant seedlings deficient in cryptochrome, phytochrome, or phototropin, suggesting that none of the known photoreceptors is the major UV-B photoreceptor. Some null mutants in DNA repair enzymes show hypersensitivity to UV-B, suggesting that even at low fluence rates, direct damage to DNA may be a component of the response to UV-B. We have now screened nearly 38,000 T-DNA insertional mutants for plants that are altered in this response and planted 1451 of those to generate seed. Thus far, we have collected T3 seed from 789 lines and carried out fluence response curves on 154 of those. To date, 21 lines have demonstrated reduced
sensitivity to UV in a fluence response curve. Characterization of these lines continues.
PARTICIPANTS: Dr. Gary Gardner, Professor, Department of Horticultural Science, University of Minnesota, PI. Objective 2: Dr. Jerry D. Cohen, Professor, Department of Horticultural Science, University of Minnesota, Co-PI. Dr. Lana S. Barkawi, Research Associate, Department of Horticultural Science, University of Minnesota Ms. Xing Liu, Research Assistant, Plant Biological Science Program, University of Minnesota Objective 3: Mr. Doug Brinkman, Junior Scientist, Department of Horticultural Science, University of Minnesota Ms. Heather Loehrer, Undergraduate Research Assistant, Undergraduate Research Opportunities Program, University of Minnesota
Impacts
The results of this research could lead to a new market concept of a branded product line of produce certified to be high in disease-preventing compounds. The value-added agricultural opportunity will benefit consumers, the processing industry, and farmers. An understanding of UV-B photoperception in plants could lead to strategies to increase photosynthetic productivity, to regulate plant growth and development in a positive way, and to manipulate metabolic pathways in phenolic biosynthesis for the benefit of both plants and humans.
Publications
- Gardner, G., and Craker, L. E. 2007. Plants as Food and Medicine: The Utilization and Development of Horticultural Plants for Human Health, Proceedings, XXVII International Horticultural Congress, Acta Horticulturae 765, Int. Soc. Hort. Sci., Leuven, Belgium.
- Barkawi, L., Gardner, G., and Cohen, J.D. 2007. Roles for Multiple Auxin Biosynthetic Pathways. Plant Biology & Botany 2007 Joint Congress, Annual Meeting, American Society of Plant Biologists, Chicago, Illinois, July 7-11.
- Barkawi, L., Gardner, G., and Cohen, J.D. 2007. Roles for Multiple Auxin Biosynthetic Pathways. 19th International Plant Growth Substances Conference, Puerto Vallarta, Mexico, July 21-25.
- Gardner, G., Lin, C., Tobin, E.M., Loehrer, H., and Brinkman, D. 2007. The Effect of UV-B Irradiation on the Growth of Etiolated Arabidopsis Seedlings. Plant Biology & Botany 2007 Joint Congress, Annual Meeting, American Society of Plant Biologists, Chicago, Illinois, July 7-11.
- Loehrer, H., and Gardner, G. 2007. Action Spectrum of UV-B Inhibition of Hypocotyl Growth in Arabidopsis thaliana. University of Minnesota Undergraduate Symposium, Minneapolis, Minnesota, April 18.
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Progress 01/01/06 to 12/31/06
Outputs
The first objective of this project is to develop plant-derived foods or products that benefit human health by determining the effect of light and temperature on the content of cancer-preventing compounds in vegetables. As recently reported, our data indicate that gluconasturtiin content in watercress can be increased by growing plants at lower temperatures, under long days, and by exposure to R light. Our second objective, in collaboration with J. D. Cohen, is to determine the relationship between the biosynthesis of the plant hormone auxin and its specific polar transport. Our approach is to determine by specific labeling pattern if the IAA that enters the polar auxin transport (PAT) system has a specific metabolic origin that differentiates it from the bulk of the IAA in the tissue under normal, wounding, and stress conditions. We have measured PAT in maize coleoptile sections and in intact seedlings. 3H-tryptophan and 14C-anthranilate, precursors whose relative
incorporation into IAA reveal which pathways is being favored, have been used in the donor blocks, and we have seen evidence of polar transport of the respective labels that is partially inhibited by 1-naphthylphthalamic acid (NPA), a PAT inhibitor. We are using HPLC with both UV and radio detectors to separate and identify the labeled compounds. We are also optimizing stable-isotope labeling techniques using 2H,15N-tryptophan and 15N-anthranilate in order to unequivocally determine the labeling of IAA and which pathway is being used. Our third objective is to characterize novel ways in which plants respond to visible and ultraviolet light and identify methods by which managing light quality can help to manage crop growth. In collaboration with E. Tobin and C. Lin at UCLA we have begun a search for a UV-B (280-320 nm) photoreceptor in plants. Very little is known about how plants perceive UV-B light. We seek to understand the effects of UV-B irradiation on plant growth by using
physiological, biochemical, and genetic approaches to characterize inhibition of Arabidopsis hypocotyl growth by UV-B. Specifically, we are: 1) defining and characterizing the response of etiolated Arabidopsis seedlings to low fluence UV light; 2) characterizing the response in known mutants of photoreceptor genes and other genes involved in UV signal transduction and DNA repair; and 3) attempting to identify and characterize mutants of Arabidopsis, and the corresponding genes and gene products, which demonstrate a decreased sensitivity to UV-B. Because inhibition of hypocotyl growth by pulses of UV light occurs in mutants deficient in phytochrome, cryptochrome, or phototropin, we conclude that it cannot be attributed to the action of these known photoreceptors. We have now screened nearly 35,000 T-DNA insertional mutants that are altered in this response and planted 1280 of those to generate seed. Thus far, we have collected T3 seed from 316 lines and carried out fluence response
curves on 44 of those. To date, only five lines have demonstrated reduced sensitivity to UV in a fluence response curve. Characterization of these lines is underway.
Impacts
The results of this research could lead to a new market concept of a branded product line of produce certified to be high in disease-preventing compounds. The value-added agricultural opportunity will benefit consumers, the processing industry, and farmers. An understanding of UV-B photoperception in plants could lead to strategies to increase photosynthetic productivity, to regulate plant growth and development in a positive way, and to manipulate metabolic pathways in phenolic biosynthesis for the benefit of both plants and humans.
Publications
- Kettenring, K. M., Gardner, G., and Galatowitsch, S. M. 2006. Effect of light on seed germination of eight Carex wetland species. Annals of Botany 98: 869-874.
- Engelen-Eigles, G., Holden, G., Cohen, J.D., and Gardner, G. 2006. The effect of temperature, photoperiod, and light quality on gluconasturtiin concentration in watercress (Nasturtium officinale). J. Agric. Food Chem. 54: 328-334.
- Engelen-Eigles, G., Holden, G., Cohen, J. D., and Gardner G. 2006. The effect of temperature, photoperiod, and light quality on gluconasturtiin levels in watercress (Nasturtium officinale). in Symposium S-03, Plants as Food and Medicine: The Utilization and Development of Horticultural Plants for Human Health, 27th International Horticultural Congress, Seoul, Korea, August 13-19.
- Plate, A. Y. A., Gallaher, D. D. 2006. Effects of indole-3-carbinol and phenethyl isothiocyanate on colon carcinogenesis induced by azoxymethane in rats. Carcinogenesis 27:287-92.
- Plate, A. Y., and Gallaher, D. D. 2006. Fresh cruciferous vegetables decrease risk of colon cancer in carcinogen-treated rats. Experimental Biology 2006. The FASEB Journal 20: A150.
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Progress 01/01/05 to 12/31/05
Outputs
A major objective of this project is to develop plant-derived foods or products that benefit human health by determining the effect of light and temperature on the content of cancer-preventing compounds in vegetables. As part of our work to maximize the concentration of cancer chemopreventive agents in vegetables, the effects of different growth regimes on gluconasturtiin content in watercress (Nasturtium officinale R. Br.) were investigated. As previously reported, our data indicate that gluconasturtiin content in watercress can be increased by growing plants at lower temperatures, under long days, and by exposure to R light. Another aspect of this objective, in collaboration with Carl Rosen and Vincent Fritz, has been to examine the effects of varying regimes of nitrogen and sulfur fertility on glucosinolate content in field-grown cabbage. Results indicate that at sub-optimal nitrogen levels, in terms of yield, increased sulfur will cause an increase in total
glucosinolates and in glucobrassicin, the predominant glucosinolate in cabbage. The second objective of this project, in collaboration with Jerry D. Cohen, is to determine the relationship between the biosynthesis of the plant hormone auxin and its specific polar transport. Our approach is to determine by specific labeling pattern if the IAA that enters the polar transport system has a specific metabolic origin that differentiates it from the bulk of the IAA in the tissue under normal, wounding, and stress conditions. During 2005 we received funding from the USDA CREES NRICGP Agricultural Plant Biochemistry Program to support this work in a project entitled: Roles for Multiple Auxin Biosynthetic Pathways. Experiments have just begun to establish the specific bioassay systems to carry out this project. A third objective of this project is to characterize novel ways in which plants respond to visible and ultraviolet light and identify methods by which managing light quality can help to
manage crop growth. We have initiated experiments in collaboration with Professors Elaine Tobin and Chentao Lin at UCLA in a search for a UV-B (280-320 nm) photoreceptor in plants, about which very little is known, using the model plant Arabidopsis thaliana. Inhibition of elongation growth of etiolated Arabidopsis hypocotyls by pulses of UV light appears to be a suitable UV-B-specific response. We have characterized the photobiological properties of this response and, because it occurs in mutants deficient in phytochrome, cryptochrome, or phototropin, we conclude that it cannot be attributed to the action of these known photoreceptors. We have begun a large scale effort to identify T-DNA insertion mutants of Arabidopsis that are altered in this UV-B response, and our work in 2006 will continue characterization of the response and identification of genetic lesions in the pathway with the goal of identifying the photoreceptor(s) responsible for the photomorphogenetic action of UV-B
light.
Impacts
The results of this research could lead to a new market concept of a branded product line of produce certified to be high in disease-preventing compounds. The value-added agricultural opportunity will benefit consumers, the processing industry, and farmers. Ambient levels of UV-B are increasing at the surface of the earth, primarily due to the reduction of the ozone layer, and this environmental damage could have serious consequences for both human health and agricultural productivity. A basic understanding of how plants respond to UV-B could lead to new strategies for protecting crops from UV damage.
Publications
- Engelen-Eigles, G., G. Holden, J. D. Cohen, and G. Gardner, The effect of temperature, photoperiod, and light quality on gluconasturtiin concentration in watercress (Nasturtium officinale), J. Agric. Food Chem., In Press, 2005.
- Plate, A. Y. A., D. D. Gallaher. Effects of indole-3-carbinol and phenethyl isothiocyanate on colon carcinogenesis induced by azoxymethane in rats. Carcinogenesis Advance Access, published August 19, 2005.
- Plate, A. Y. A., D. L. Crankshaw, and D. D. Gallaher, The effect of anesthesia by diethyl ether or isoflurane on activity of cytochrome P450 2E1 and P450 reductases in rat liver, Anesth. Analg. 101: 1063-1064, 2005.
- Plate, A. Y., and D. D. Gallaher, Effect of cabbage and watercress on colon cancer risk in rats, 2005 Experimental Biology and XXXV International Congress of Physiological Sciences meeting abstracts, The FASEB Journal 19: Abstract#583.2, 2005.
- Gardner, G., Environmental and cultural regulation of the chemopreventive constituents of cruciferous vegetables in the diet, HortScience 40(4): 941, 2005.
- Gardner, G. M., A. H. Markhart, III, G. Engelen-Eigles, L. Y Wong, and C. J. Rosen. Methods for increasing one or more glucosinolates in a plant, U. S. Patent Application Serial No. 11054528, filed June 10, 2005.
- Rosen, C. J.,V. A. Fritz, G. M. Gardner, S. S. Hecht, S. G. Carmella, and P. M. Kenney, Cabbage Yield and Glucosinolate Concentrations as Affected by Nitrogen and Sulfur Fertility, HortScience 40(5): 1493-1498, 2005.
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Progress 01/01/04 to 12/31/04
Outputs
A major objective of this project is to develop plant-derived foods or products that benefit human health by 1) establishing effective interdisciplinary programs under the auspices of the Center for Plants and Human Health; and 2) determining the effect of light and temperature on the content of cancer-preventing compounds in vegetables. We have previously reported four topic areas around which researchable questions have developed: 1) Soy and Cardiovascular Disease; 2) Propolis and HIV; 3) Whole Grains and Diabetes; and 4) Vegetables and Chemoprevention. During the past year, two additional research interest groups have formed: 5) Botanicals. This group has focused on stability of the active agents during processing and storage of either dry or liquid-based products. A study of four plants used as hepatoprotectants (milk thistle, Schisandra, Picrorhiza, and Sophora) to evaluate mechanism of action, determine metabolism and bioavailability, optimize horticultural
procedures, and investigate stability has been proposed. 6) Mushrooms and Cancer Prevention. This group is based on an existing collaboration in the Academic Health Center on the effect of mushroom extract on prostate cancer. With the addition of expertise in mycology from the department of Plant Biology, this team has proposed a project on growth conditions and bioactivity of mushroom extracts on tumor inhibition. Major research proposals were submitted in five of these six areas during 2004. As part of our work to maximize the concentration of cancer chemopreventive agents in vegetables, the effects of different growth regimes on gluconasturtiin content in watercress (Nasturtium officinale R. Br.) were investigated. Watercress plants growing under long days contained higher gluconasturtiin content and had higher fresh weight than watercress plants growing under short days. Watercress plants growing under long days and temperatures of 15 or 10 C had a higher gluconasturtiin content,
but the fresh weight of low-temperature grown plants was much lower than that of plants grown under 20 or 25 C. Watercress plants grown under metal halide light enriched with red (R) light had a higher gluconasturtiin content compared to far-red (FR) enriched plants. Likewise, a brief R light exposure at the end of the main photoperiod resulted in higher gluconasturtiin content compared to a FR end-of-day exposure. Taken together, these data indicate that gluconasturtiin content in watercress can be increased by growing plants at lower temperatures, under long days, and by exposure to R light. Another major objective of this project is to characterize novel ways in which plants respond to visible and ultraviolet light and identify methods by which managing light quality can help to manage crop growth. We have initiated experiments in a search for a UV-B (280-320 nm) photoreceptor in plants, about which very little is known, using the model plant Arabidopsis thaliana. We are looking
for a response that is rapidly and specifically induced by UV-B light. This work is currently underway in collaboration with Professors Elaine Tobin and Chentao Lin, both at UCLA.
Impacts
The results of this research could lead to a new market concept of a branded product line of produce certified to be high in disease-preventing compounds. The value-added agricultural opportunity will benefit consumers, the processing industry, and farmers. By identifying new value-added businesses, both in growing these crops and in food preparation, this work has the potential of improving human health, providing economic opportunities in rural Minnesota, and increasing international competitiveness and profitability.
Publications
- Rosen, C. J.,V. A. Fritz, S. S. Hecht, G. M. Gardner, S. G. Carmella, and P. M. Kenney, Cabbage Yield and Glucosinolate Concentrations as Affected by Nitrogen and Sulfur Fertility, HortScience, In Press, 2005.
- Engelen-Eigles, G., G. Holden, J. D. Cohen, and G. Gardner, The effect of photoperiod, light quality, and temperature on 2-phenylethyl glucosinolate levels in watercress (Nasturtium officinale), Annual Meeting, American Society of Plant Biologists, Orlando, Florida, July 24-28, 2004.
- Plate, A Y. A., D. D. Gallaher. Effect of indole-3-carbinol and phenethyl isothiocyanate on colonic mucin staining and hepatic mixed-function oxidases in rats. Poster presentation at Experimental Biology 2004 Nutrition and Metabolism Program, Washington, D.C., April, 2004.
- Gardner, G. M., A. H. Markhart, III, G. Engelen-Eigles, L. Y Wong, and C. J. Rosen. Methods for increasing one or more glucosinolates in a plant, U.S. Provisional Patent Application Serial No. 60/542,917, filed February 9, 2004.
- Web Site: http://cphh.coafes.umn.edu, 2004.
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Progress 01/01/03 to 12/31/03
Outputs
A major objective of this project is to develop plant-derived foods or products that benefit human health by 1) establishing effective interdisciplinary programs under the auspices of the Center for Plants and Human Health; and 2) determining the effect of light and temperature on the content of cancer-preventing compounds in vegetables. The Center provides a forum for the development and interchange of information and serves as a stimulant for interdisciplinary collaboration among scientists and clinicians at the University of Minnesota who are interested in how plants and plant products may be used to improve human health and nutrition. The Center played a key role in bringing together researchers from across the University to explore possible collaborative research opportunities, identified possible funding sources, assisted in preparation of grant submissions, and provided small grants for research travel. Researchable questions have developed along several topic
areas: 1) Soy and Cardiovascular Disease. This group is interested in improving soybean genetics explicitly for the purpose of improving human health. We received preliminary funding from the Minnesota soybean growers, and we are developing a protocol for a human feeding study of soy protein isolate from germplasm differing in isoflavone and small peptide levels to determine cholesterol lowering effects. 2) Propolis and HIV. Dr. Phil Peterson and his colleagues found that propolis, a resinous material from beehives, inhibits HIV expression in cell culture. In collaboration with Dr. Peterson, we received funding from the Graduate School to characterize this activity. 3) Whole Grains and Diabetes. Minnesota is well-situated to lead in the study of nutritional and health benefits of small grains, with strengths in cereal breeding and genetics, cereal chemistry, nutrition, epidemiology, and food processing. This group is developing a protocol for a diabetes prevention and treatment study
in rat models using major fractions of whole grain. 4) Vegetables and Chemoprevention. A multi-investigator group has been working for about three years on cancer-preventing glucosinolates in cruciferous vegetables such as watercress and cabbage, with funding from the SOTA TEC Fund. As part of our overall goal to maximize the concentration of cancer chemopreventive agents in vegetables, this work has focused on whole plant studies to determine the environmental conditions that control the biosynthesis of these compounds. Emphasis has been placed on light and temperature effects on glucosinolate synthesis in watercress in controlled environment chambers. Gluconasturtiin content increased in plants grown under long days (vs. short days), in plants supplemented with red light, and in plants treated with a brief red light period at the end of the day. Temperature experiments were expanded to determine the optimal day/night conditions to reach a balance between high glucosinolate
concentration and yield. Our goal is to determine if we can combine these various treatments to define a single regime with commercial applicability to increase gluconasturtiin content in greenhouse-grown watercress.
Impacts
The results of this research could lead to a new market concept of a branded product line of produce certified to be high in disease-preventing compounds. The value-added agricultural opportunity will benefit consumers, the processing industry, and farmers. By identifying new value-added businesses, both in growing these crops and in food preparation, this work has the potential of improving human health, providing economic opportunities in rural Minnesota, and increasing international competitiveness and profitability.
Publications
- Gardner, G. The Center for Plants and Human Health: An Interdisciplinary Approach, NABC Report 14, Foods for Health: Potential, Perspectives, and Policy, National Agricultural Biotechnology Council, Ithaca, NY, pp. 289-298, 2003.
- Plate, A Y. A., D. D. Gallaher. Breakdown Products of Glucosinolates and Reduced Risk of Colon Cancer. Poster presentation at Experimental Biology 2003 Nutrition and Metabolism Program, San Diego, California, April, 2003.
- Rosen, C. J., V.A. Fritz, S.S. Hecht, S.G. Carmella, and P.M. Kenney. Cabbage yield and glucobrassicin concentrations as affected by nitrogen and sulfur fertility. Oral presentation at the Annual Meeting, American Society for Horticultural Science, Providence, RI, October 5, 2003.
- Wong, L. Y., G. Engelen-Eigles, J. Cohen, A. Markhart, and G. Gardner, The effect of water stress on 2-phenylethyl glucosinolate levels in Nasturtium officinale, Poster presentation at Annual Meeting, American Society of Plant Biologists, Denver, Colorado, August 3-7, 2002.
- Wong, L. Y., J. Cohen, , G. Gardner, and A. Markhart, The effect of defense signaling molecules on the content of 2-phenylethyl glucosinolate levels in Nasturtium officinale R. Br., Poster presentation at Annual Meeting, American Society of Plant Biologists, Honolulu, Hawaii, July 25-30, 2003.
- Gardner, G., K. Kaehler, 2003. Center for Plants and Human Health Web Site: http://cphh.coafes.umn.edu
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