Progress 07/01/07 to 06/30/10
Outputs
OUTPUTS: Results of this project have been disseminated to public audiences, and to national and international scientific communities consistently and explicitly. Over the course of the project, I was invited to present project results at multiple international scientific events: Gordon Conference for Floral and Vegetative Volatiles (Feb 2007, Switzerland; Aug 2009, Oxford, England), and the 5th International Poplar Symposium (Orvieto, Italy, Sep 2010). This represents an exceptional reflection on the recognized value of the work. Results were also presented orally at two meetings of the Ecological Society of America (2008, 2010), one meeting of the Entomological Society of America (2009), the Plant Animal Genome Meeting (2009). Poster presentations of the results were given in diverse venues throughout the course of the granting period. Apart from scientific meeting and symposia, I have dessiminated the results as invited seminars at multiple institutions in the United States (Purdueand across the world (Australia, New Zealand, Peru, England). In addition, I have presented invited seminars the results to the Botany and Plant Pathology Department at Purdue University (March 2009). Thus, a diverse group of scientists from ecologists to molecular geneticists have been exposed to the research through conference oral and poster presentations. Further, the work attracted the interest of two graduate students and multiple undergraduate students at Penn State who engaged in independent study projects related to the goals and objectives of the grant. One of the graduate students is currently preparing a manuscript for submission based on his work related to the project objectives. While none of these projects has yet resulted in a published manuscript, the goal of providing a training environment for undergraduate students was realized during the granting period. In terms of knowledge transfer to public audiences, the results were included in two formal workshops prepared for the Women in the Sciences and Engineering (WISE) Institute at Penn State (July 2007-2009) and Global Explorers workshops in the Peruvian Amazon (2009-2010). The WISE summer camp introduces bright young female high school students to ongoing research projects at Penn State. As part of this workshop, I introduced students to the concept that plants can communicate using airborne volatile compounds and provided hands-on activities to allow the students to experience how we actually measure the ability of the plants to sense volatiles and engage defenses against herbivorous insects. WISE participants were able to setup simple volatile collection experiments, practice the laboratory procedures involved in eluting volatile samples, and observe the operation gas chromatograph to detect and quantify the volatile compounds. The Global Explorers program provides hands-on ecology field experience for middle school students. I developed and implemented workshops on plant-herbivore interactions that made direct use of my scientific findings on plant priming and signaling with volatiles. PARTICIPANTS: Dr. Christopher J. Frost - Project Director, Postdoctoral Fellow. Responsibilities: conceiving and conducting experiments, analyzing data, writing publications, and presenting talks and seminars. As a postdoctoral researcher, this project is providing training and professional development opportunities on how to manage time, goals of the project, and most importantly, money. This is invaluable experience preparing me for position as an academic research with grant-management responsibilities. In addition, I have an active role in the advising of a number of graduate and undergraduate students, which has provided professional development for both me and the students. TARGET AUDIENCES: The work resulting from this grant adds to basic and applied knowledge of plant-insect interactions, and will therefore serve insect and plant scientists. Because my work also involves an economically significant "crop" (hybrid poplar) that has received important attention as a potential source of biofuel and also as a carbon sink to ameliorate increasing atmospheric carbon dioxide concentrations, the research also has the potential to serve crop scientists and, eventually, the general public. The same is also true for the collaboration that has resulted to investigate the same phenomenon in blueberry, also a high value economic crop. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The objectives of the grant have, by in large, been achieved. In the first year, I demonstrated a clear role for herbivore-induced plant volatiles in within-plant wound signaling. The concept of within-plant wound signaling is now well supported and, based on this, I was invited to produce a foundational critique and review of plant defense priming. Both of these manuscripts have been well cited (40+ citations) in the short time they have been in the literature. Priming involves the pre-emptive activation of certain defense pathways without, in theory, engaging fully induced defenses and the costs associated with them. Most importantly, our demonstration of the existence of defense priming leads to the potential to exploit priming mechanisms in agricultural applications provided we develop a clear understanding of the mechanisms involved. I then further investigated the molecular mechanisms involved in the phenomenon of plant defense priming, as I outlined in the grant's specific aims. I demonstrated that a single volatile compound in the class of "green-leaf volatiles", specifically cis-3-hexenyl acetate, can prime plant leaves for an enhanced defense response. Using spotted microarrays, we have identified candidate genes that may be responsible for triggering such a priming response. In addition, I use an active collaboration to demonstrate the comparative biology of plant defense priming and within-plant signaling, results of which have been published in the Journal of Chemical Ecology. While not explicitly in the specific aims of the grant, our demonstration of within-plant signaling in an agriculturally important shrub species (Blueberry) is nonetheless highly relevant to successfully addressing the specific aims presented in the grant. The final aspects of the grant have yet to be published but are nonetheless exciting. I used full-genome commercial microarrays to identify gene networks regulated by exposure to three different volatile compounds (without any wounding). These array data will be, as outlined in the grant, deposited in GEO for open access by the scientific community, and the gene networks identified will be investigated further with functional genomic techniques. The bottom line is that this USDA funding has shown that plants can detect and respond to volatile compounds associated with herbivore-induced wounding, and that these compounds produce reproducible changes to plant transcriptomes. These results provide the basis for exploring the potential to use volatile signals in an applied manner in agricultural settings to reduce insect pest damage by heightening natural defenses of plants. In addition to these impacts, the grant has supported the training of multiple undergraduate students in the Carlson laboratory.
Publications
- Barakat, A., A. Bagniewska-Zadworna, C.J. Frost, and J.E. Carlson. 2010. Differential and coordinate response of CAD family genes against insect herbivory in hybrid Populus (P. deltoides x P. nigra). BMC Plant Biology. 10:100
- Rodriguez-Saona, C.R. and C.J. Frost. 2010. New evidence for a multi-functional role of herbivore-induced plant volatiles in defense against herbivores. Plant Signaling and Behavior. 5:58-60
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Progress 07/01/08 to 06/30/09
Outputs
OUTPUTS: Results of this project, though the project is ongoing, have been disseminated to public audiences, as well as to both the national and international scientific community. During the past year, at the international level, the PI was invited to present current results at the Gordon Conference for Floral and Vegetative Volatiles (Aug 2009, Oxford, England) and at the University of Warwick in England (September 2008). A current version of the results were also presented at the Ecological Society of America Annual Meeting (August 2008, Milwaukee, WI). In addition, the Project Director was invited to present the results to the Botany and Plant Pathology Department at Purdue University (March 2009). The work continues to attract the interest of undergraduate students at Penn State who are currently involved in independent study projects related to the goals and objectives of the grant. In terms of knowledge transfer to public audiences, the results were also included in a workshop organized by the De Moraes lab for the Women in the Sciences and Engineering (WISE) Institute at Penn State (July 2009). The WISE summer camp introduces bright young female high school students to ongoing research projects at Penn State. As part of this workshop, we introduced the students to the concept that plants can communicate using airborne volatile compounds and provided hands-on activities to allow the students to experience how we actually measure the ability of the plants to sense volatiles and engage defenses against herbivorous insects. WISE participants were able to setup simple volatile collection experiment, practice the laboratory procedures involved in eluting volatile samples, and observe the operation gas chromatograph to detect and quantify the volatile compounds. PARTICIPANTS: Dr. Christopher J. Frost - Project Director, Postdoctoral Fellow. Responsibilities: conceiving and conducting experiments, analyzing data, writing publications, and presenting talks and seminars. As a postdoctoral researcher, this project is providing training and professional development opportunities on how to manage time, goals of the project, and most importantly, money. This is invaluable experience preparing me for position as an academic research with grant-management responsibilities. In addition, I have an active role in the advising of a number of graduate and undergraduate students, which has provided professional development for both me and the students. Dr. John E. Carlson - Faculty member of the Department of Forestry and postdoctoral supervisor. Responsibilities: providing advice and expertise in relation plant genetics and molecular biology; providing assistance in producing publications. Dr. Consuelo De Moraes - Faculty member of the Department of Entomology and postdoctoral supervisor. Responsibilities: providing advice and expertise in relation to chemical ecology; providing assistance in producing publications. TARGET AUDIENCES: The work resulting from this grant adds to basic and applied knowledge of plant-insect interactions, and will therefore serve insect and plant scientists. Because my work also involves an economically significant "crop" (hybrid poplar) that has received important attention as a potential source of biofuel and also as a carbon sink to ameliorate increasing atmospheric carbon dioxide concentrations, the research also has the potential to serve crop scientists and, eventually, the general public. The same is also true for the collaboration that has resulted to investigate the same phenomenon in blueberry, also a high value economic crop. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The second year of this grant has contributed significantly to the results of the first year of the grant. In the first year, we (1) demonstrated a clear role for herbivore-induced plant volatiles in within-plant wound signaling and (2) produced a foundational critique and review of plant defense priming. Priming involves the pre-emptive activation of certain defense pathways without, in theory, engaging fully induced defenses and the costs associated with them. Most importantly, our demonstration of the existence of defense priming leads to the potential to exploit priming mechanisms in agricultural applications provided we develop a clear understanding of the mechanisms involved. In this second year, we have further investigated the molecular mechanisms involved in the phenomenon of plant defense priming, as we outlined in the grant's specific aims. We have demonstrated that a single volatile compound in the class of "green-leaf volatiles", specifically cis-3-hexenyl acetate, can prime plant leaves for an enhanced defense response. Using spotted microarrays, we have identified candidate genes that may be responsible for triggering such a priming response. The first manuscript in this regard has been published in New Phytologist. In addition, the PI of the grant has engaged in a collaboration to explore the comparative biology of plant defense priming and within-plant signaling, results of which have been published in the Journal of Chemical Ecology. While not explicitly in the specific aims of the grant, our demonstration of within-plant signaling in an agriculturally important shrub species (Blueberry) is nonetheless highly relevant to successfully addressing the specific aims presented in the grant. For the remaining year of the grant, we will further investigate the molecular mechanisms of priming by interrogating the candidate genes from the microarray, as well as expanding to conduct microarray analysis on leaves exposed to different volatile compounds. In addition to these impacts, the grant has supported the training of multiple undergraduate students in the Carlson laboratory.
Publications
- Rodriguez-Saona, C.R., L.E. Rodriguez-Saona, and C.J. Frost. 2009. Herbivore-induced volatiles in the perennial shrub, Vaccinium corymbosum, and their role in inter-branch signaling. Journal of Chemical Ecology 35(2):163-175
- Frost, C.J., M.C. Mescher, C. Dervinis, J.M. Davis, J.E. Carlson, and C.M. De Moraes. 2008. Priming defense genes and metabolites in hybrid poplar by the green leaf volatile cis-3-hexenyl acetate. New Phytologist 180:722-734.
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Progress 07/01/07 to 06/30/08
Outputs
OUTPUTS: Results of this project, though the project is ongoing, have been disseminated to public audiences, as well as to both the national and international scientific community. At the international level, the PI was invited to present current results at the Gordon Conference for Floral and Vegetative Volatiles (Oct 2007, Les Diabelerets, Switzerland) and the Pan American Advanced Studies Institute workshop on Chemical Biology in the Tropics (June 2008, Lima and Madre de Dios, Peru). A current version of the results were also presented at the 25th Annual Meeting of the International Society for Chemical Ecology (August 2008, State College, PA). In addition, the Project Director was invited to present the results to the Forestry Department of Northern Arizona University (May 2008) and at the annual conference of the Ecological Society of America (August 2008). The work has further attracted the interest of two undergraduate students at Penn State who are currently involved in independent study projects related to the goals and objectives of the grant. In terms of knowledge transfer to public audiences, the results were also included in a workshop organized by the De Moraes lab for the Women in the Sciences and Engineering (WISE) Institute at Penn State (July 2008). The WISE summer camp introduces bright young female high school students to ongoing research projects at Penn State. As part of this workshop, we introduced the students to the concept that plants can communicate using airborne volatile compounds and provided hands-on activities to allow the students to experience how we actually measure the ability of the plants to sense volatiles and engage defenses against herbivorous insects. WISE participants were able to setup simple volatile collection experiment, practice the laboratory procedures involved in eluting volatile samples, and observe the operation gas chromatograph to detect and quantify the volatile compounds. PARTICIPANTS: Dr. Christopher J. Frost - Project Director, Postdoctoral Fellow. Responsibilities: conceiving and conducting experiments, analyzing data, writing publications, and presenting talks and seminars. As a postdoctoral researcher, this project is providing training and professional development opportunities on how to manage time, goals of the project, and most importantly, money. This is invaluable experience preparing me for position as an academic research with grant-management responsibilities. In addition, I have an active role in the advising of a number of graduate and undergraduate students, which has provided professional development for both me and the students. Dr. John E. Carlson - Faculty member of the Department of Forestry and postdoctoral supervisor. Responsibilities: providing advice and expertise in relation plant genetics and molecular biology; providing assistance in producing publications. Dr. Consuelo De Moraes - Faculty member of the Department of Entomology and postdoctoral supervisor. Responsibilities: providing advice and expertise in relation to chemical ecology; providing assistance in producing publications. Dr. Mark C. Mescher - Faculty member of the Department of Entomology. Responsibilities: providing advice in relation to chemical ecology; providing assistance in producing publications. TARGET AUDIENCES: The work resulting from this grant adds to basic and applied knowledge of plant-insect interactions, and will therefore serve insect and plant scientists. Because my work also involves an economically significant "crop" (hybrid poplar) that has received important attention as a potential source of biofuel and also as a carbon sink to ameliorate increasing atmospheric carbon dioxide concentrations, the research also has the potential to serve crop scientists and, eventually, the general public. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
In the first year of this grant, we have contributed significantly to the field (1) by demonstrating a clear role for herbivore-induced plant volatiles in within-plant wound signaling and (2) producing a foundational critique and review of plant defense priming. First, we have shown that herbivore-induced volatile compounds can serve a signaling function between parts of an individual plant, and this grant supported this work. The resources and salary support provided by the grant were integral to this contribution to our scientific knowledge. Within-plant volatile signaling is an important impact in the field of plant-to-plant signaling; previous studies reporting the role of volatiles as wound signals were criticized due to the distance a volatile compound would have to travel and maintain sufficient concentration to be received. Our results indicate that the distance a volatile signal has been shown to travel in nature can occur within a plant. These volatile compounds may induce defenses directly, but may more likely prime defenses, which lead us to our second important contribution funded by the grant in the current year. Second, this grant has supported the writing an publication of a review article on plant defense priming; the article has been cited frequently in the few months since its publication. Defense priming in plants occurs when a plant receives a signal that indicates an increased potential for attack. Priming involves the pre-emptive activation of certain defense pathways without, in theory, engaging fully induced defenses and the costs associated with them. Most importantly, our demonstration of the existence of defense priming leads to the potential to exploit priming mechanisms in agricultural applications provided we develop a clear understanding of the mechanisms involved. In the next year, the grant will support further investigation of the molecular mechanisms involved in priming, as indicated in the grant's specific aims. The first manuscript in the effort to elucidate molecular mechanisms and responses of priming has already been accepted and is in press at New Phytologist (though is not included in the publication list for the current fiscal year). In addition to these impacts, the grant has supported the training of multiple undergraduate students in both the De Moraes and Carlson laboratories.
Publications
- Frost, C.J., M.C. Mescher, J.E. Carlson, and C.M. De Moraes. 2008. Why do distance limitations exist on plant-plant signaling via airborne volatiles Plant Signaling and Behavior 3(7):466-468
- Frost, C.J., M.C. Mescher, J.E. Carlson, and C.M. De Moraes. 2008. Plant defense priming against herbivores: getting ready for a different battle. Plant Physiology 146:818-824
- Frost C.J., H.M. Appel, J.E. Carlson, M.C. Mescher, C.M. De Moraes, and J.C. Schultz. 2007. Within-plant signaling via volatiles overcomes vascular constraints on systemic signaling and primes responses against herbivores. Ecology Letters 10:490-498
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