Progress 10/01/19 to 09/30/20
Outputs Target Audience:Research provides a basic knowledge about biosynthesis of plant-produced volatile compounds and their emission into the atmosphere and release of natural products released into the rhizosphere. The work is important for plant biologists, biochemists, atmospheric chemists, and scientists involved in plant metabolic engineering and investigation of plant-plant and plant insect interactions. This research is also of interest for scientists working in floriculture, flavor, cosmetic and fragrance industries, as well as those working to develop novel herbicides and other agricultural products. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This work provided strong multidisciplinary training in plant biochemistry, molecular biology, genetics, in vivo isotopic labeling, GC-MS and LC-MS-based metabolic profiling and integrative modeling for undergraduate and graduate students, as well as post-doctoral scientists. Dr. Joseph Lynch - Research Assistant (Dudareva): Analysis of transgenic petunia plants with overexpression of PhCM2 and biochemical interface between Phe and auxin biosynthesis. Pan Liao - Post-doc (Dudareva): Analysis of PhABCG12 downregulation on wax composition and volatile emission. Itay Maoz - Post-doc (Dudareva): Analysis of PhLTP(s) downregulation on volatile emission. Xing-Qi (David) Huang - Post-doc (Dudareva): Identification of transporter involved in shikimate transport out of plastids. Elucidation of benzaldehyde biosynthesis in plants. Shannon Sterling - Graduate Student (Dudareva) Investigation of molecular mechanisms of natural fumigation Mithila Shukla - Graduate Student (Dudareva) Investigating flux through the shikimate pathway Ji Hee Lee - Graduate Student (Dudareva) Investigating the role of vesicle trafficking in VOC emission Dr. Manoj Ghaste - Post-doc (Widhalm): Dicamba volatility research. Rachel McCoy - Ph.D. candidate (Widhalm): Investigation of plant quinone metabolism. Thiti Suttiyut - Ph.D. student (Widhalm): Elucidation of cytoplasmic geranyl diphosphate formation in Lithospermum erythrorhizon George Meyer - Ph.D. student (Widhalm): Investigation of juglone resistance mechanisms in plants Awards: Dr. Postdoc Joseph Lynch received 2020 Linda Siersema Staff Excellence Award, Purdue University, Biochemistry Department, May, 2020. Graduate student Shannon Stirling received a Bird Stair Graduate Research Fellowship ($5,000) for her project "KAI2 acts as a receptor for germacrene D and is essential for stigma development", Spring 2020. Graduate student Rachel McCoy received the "Outstanding Graduate Research Award, Ph.D." in the Department of Horticulture and Landscape Architecture How have the results been disseminated to communities of interest?Invited seminars and invited speaker at meetings: 2019 Ball Horticultural Company, West Chicago, IL, November 22. (Dudareva) 2019 University Jean Monnet Saint-Etienne, University de Lyon, Saint-Etienne, France, October 14. (Dudareva) 2019 Biochemistry club (for undergraduate students), Department of Biochemistry, Purdue University, October 1. (Dudareva) 2020 Plant Biology 2020 ASPB Annual Meeting, Washington, DC, July 27 -31, 2020. (Dudareva) 2020 Biochemistry Horizons Symposium "From Organelles to Metabolites and Beyond", Purdue University, West Lafayette, IN, March 6. (Dudareva) 2020 ABC2020 Keynote Plenary Lecture, FEBS Special Meeting 2020 ATP-Binding Cassette (ABC) Proteins: From Multidrug Resistance to Genetic Disease, Innsbruck, Austria, March 1-7. (Dudareva) 2019 "Small Molecules in Plant Research: Chemistry and Biology Come Together Symposium", Valencia, Spain, December 10-11. (Dudareva) 2019 2019 International Plant Biology Workshop at UCSD "Plant Synthetic Biology and Genome Engineering, University of California San Diego, San Diego, CA, November 4. (Dudareva) 2020 Investigating the metabolic origins of specialized plant quinones. Horticulture Research Symposium. Nanjing, China. Note: seminar given online due to COVID-19. (Widhalm) 2020 Investigating the metabolic origins and pathways of specialized plant 1,4-naphthoquinones. University of Illinois at Urbana-Champaign, PMPB seminar series. Champaign, IL. (Widhalm) What do you plan to do during the next reporting period to accomplish the goals?We will continue to investigate the functions, biosynthesis and mode of trafficking of secondary metabolites into the environment using multidisciplinary approaches. We will specifically study the role of vesicles and LTPs in VOC emission from flowers and release of allelochemicals from roots.
Impacts What was accomplished under these goals?
Plants synthesize an amazing diversity of volatile organic compounds (VOCs) that are important for reproduction and defense, serve as practical products for humans, and influence atmospheric chemistry and climate. To date, the chemistry of plant volatiles is well understood, however, little is known about the biosynthesis of this diverse group of compounds and their release from the cell to the atmosphere. Phenylpropanoid compounds constitute the second largest class of plant volatiles, which originate from the aromatic amino acid phenylalanine (Phe). In plants Phe is synthesized predominantly via the arogenate pathway in plastids. However, we have recently demonstrated that Phe is also synthesized in the cytosol via the microbial-like phenylpyruvate pathway, which branches from the known plastidial arogenate pathway at chorismate. In contrast to the arogenate pathway, the phenylpyruvate route is subject to less stringent feedback regulation, because cytosolic chorismate mutase 2 (CM2), which catalyzes the initial step in this pathway, is insensitive to allosteric regulation by aromatic amino acids. Thus, we investigated the metabolic consequences of altering carbon flux towards the cytosolic phenylpyruvate pathway in Petunia hybrida flowers, which typically produce high levels of Phe and Phe-derived benzenoid/phenylpropanoid volatiles. Overexpression of petunia chorismate mutase 2 (PhCM2) increased flux in cytosolic phenylalanine biosynthesis, but paradoxically decreased the levels of phenylalanine and phenylalanine-derived volatiles. Concomitantly, the levels of auxins, including indole-3-acetic acid and its precursor indole-3-pyruvic acid, were elevated. Biochemical and genetic analyses revealed the existence of metabolic crosstalk between the cytosolic phenylalanine biosynthesis and tryptophan-dependent auxin biosynthesis mediated by an aminotransferase that uses cytosolic phenylalanine biosynthetic pathway metabolites as amino acceptors for auxin formation. Plants synthesize volatile organic compounds (VOCs) to attract pollinators and beneficial microorganisms, to defend themselves against herbivores and pathogens and for plant-plant communication. The cuticle is the final physical barrier for VOCs to cross in most plant cells. Due to their hydrophobicity, the rate of VOC transport should depend on the physicochemical properties of the compound itself (diffusivity and solubility in the cuticle) and the cuticle composition and thickness. Although cuticle structure and composition vary considerably between plants, organs and developmental stages, it is commonly composed of cutin and cuticular wax, the latter of which is embedded in and deposited on the surface of the cutin matrix. The cuticular wax is a semi-crystalline mixture of alkanes, aldehydes, primary and secondary alcohols, ketones and esters, all derived from very-long-chain fatty acids. The cuticle generally acts as a molecular transport barrier, protecting tissues from stresses and preventing organ fusion during plant development. While the role of the cuticle in transpirational water flux is well established and extensive prior research provides knowledge about the interaction of atmospheric VOCs with the cuticle, how the cuticle is involved in the release of hydrophobic volatiles into the atmosphere remains an unresolved question. We used Petunia hybrida flowers with a combination of reverse-genetic and chemical approaches to investigate the role of the cuticle in the emission process. We show that reduction in cuticle thickness not only alters VOC emission, but also leads to redistribution of VOC internal pools and feedback inhibition of VOC biosynthesis. While VOCs also play important roles belowground, so do plant exudates released from roots containing non-volatile compounds. Unlike VOCs, however, the roles that these compounds play in mediating plant-biotic interactions is poorly understood. Moreover, little is known about biosynthesis of these compounds and the mechanisms responsible for their release from the cell into the rhizosphere. Specialized 1,4-naphthoquinones (1,4-NQ) have emerged as a major class of compounds involved in belowground plant-biotic interactions. Plants collectively synthesize hundreds of 1,4-NQs proposed to play roles in various plant-plant, plant-microbe and plant-animal interactions. Based on developments in understanding of plant metabolic networks, reinterpretations of classical tracer studies suggest that 1,4-NQs are synthesized through several routes. We have made major progress on understanding one of these routes, that which leads to shikonin. Shikonin is produced by the medicinal plant Lithospermum erythrorhizon (red gromwell; zicao). Roots from L. erythrorhizon have been used for centuries based on the antiviral and wound- healing properties produced from the bioactive compound shikonin and its derivatives. Shikonin also functions as an allelochemical when released into the soil. More recently, shikonin, its enantiomer alkannin, and several other shikonin/alkannin derivatives have collectively emerged as valuable natural colorants and as novel drug scaffolds. Despite several transcriptomes and proteomes having been generated from L. erythrorhizon, a reference genome is still unavailable. This has limited investigations into elucidating the shikonin/ alkannin pathway and understanding its evolutionary and ecological significance. In this study, we obtained a de novo genome assembly for L. erythrorhizon using a combination of Oxford Nanopore long-read and Illumina short-read sequencing technologies. The resulting genome is ∼367.41 Mb long, with a contig N50 size of 314.31 kb and 27,720 predicted protein-coding genes. Using the L. erythrorhizon genome, we identified several additional p- hydroxybenzoate:geranyltransferase (PGT) homologs and provide insight into their evolutionary history. Phylogenetic analysis of prenyltransferases suggests that PGTs originated in a common ancestor of modern shikonin/alkannin- producing Boraginaceous species, likely from a retrotransposition-derived duplication event of an ancestral prenyltransferase gene. Furthermore, knocking down expression of LePGT1 in L. erythrorhizon hairy root lines revealed that LePGT1 is predominantly responsible for shikonin production early in culture establishment. Taken together, the reference genome reported in this study and the provided analysis on the evolutionary origin of shikonin/alkannin biosynthesis will guide elucidation of the remainder of the pathway.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Bornowski N, Hamilton JP, Liao P, Wood JC, Dudareva N, Buell CB. 2020. Genome sequencing of four culinary herbs reveals terpenoid genes underlying chemodiversity in the Nepetoideae, DNA Research, 27 (3), dsaa016.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Lynch JH and Dudareva N. 2020. Aromatic amino acids: A complex network ripe for future exploration. Trends in Plant Sci., 25: 670-681.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Lynch JH, Qian Y, Guo L, Maoz I, Huang X-Q, Garcia A, Louie G, Bowman ME, Noel JP, Morgan JA, Dudareva N. 2020. Modulation of auxin formation by the cytosolic phenylalanine biosynthetic pathway, Nature Chem. Biol., 16: 850-856.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Lichman BR, Godden GT, Hamilton JP, Palmer L, Kamileen MO, Zhao D, Vaillancourt B, Wood J, Sun M, Kinser TJ, Henry LK, Lopez CR, Dudareva N, Soltis DE, Soltis PS, Buell CR, OConnor SE. 2020. The evolutionary origins of the cat attractant nepetalactone in catnip, Science Advances, 6: eaba0721.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Hivert G, Davidovich-Rikanati R, Bar E, Sitrit Y, Schaffer A, Dudareva N, Lewinsohn E. 2020. Prenyltransferases catalyzing geranyldiphosphate formation in tomato fruit. Plant Sci., 296: 110504
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Boachon B, Burdloff Y, Ruan J-X, Rojo R, Vincent B, Junker RR, Bringel F, Lesot A, Henry L, Bassard J-E, Mathieu S, Allouche L, Kaplan I, Dudareva N, Vuilleumier S,
Miesch L, Andr� F, Navrot N, Chen X-Y, Werck-Reichhart D. 2019. A promiscuous CYP706A3 reduces terpene volatile emission from Arabidopsis flowers, with impacts on florivores and floral microbiome. The Plant Cell, 31: 2947-2972.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Islam AKMM and Widhalm JR. (2020) Agricultural uses of juglone: Opportunities and challenges. Agronomy, 10, 1500.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Ghaste M, Hayden N, Osterhold MJ, Young JM, Young BG, and Widhalm JR*. (2020) Evaluation of a stable isotope-based direct quantification method for dicamba analysis from air and water using single-quadrupole LCMS. Molecules, 25(16), 3649.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Auber RP, Suttiyut T, McCoy RM, Ghaste M, Crook JW, Pendleton AL, Widhalm JR*, and Wisecaver JH*. (2020) Hybrid de novo genome assembly of red gromwell (Lithospermum erythrorhizon) reveals evolutionary insights into shikonin biosynthesis. Horticulture Research, 7:82.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
McCoy RM, Meyer GW, Rhodes D, Murray GC, Sors TG, and Widhalm JR*. (2020) Investigation of the foliar incorporation and stability of isotopically labeled amino acids applied to turfgrass. Agronomy, 10, 358.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Li Y, Brooks M, Yeoh-Wang J, McCoy RM, Rock T, Pasquino A, Moon CI, Patrick RM, Tanurdzic M, Ruffel S, Widhalm JR, McCombie WR, and Coruzzi GM. (2020) SDG8-mediated histone methylation and RNA processing function in the response to nitrate signaling. Plant Physiology, 182:215-227.
- Type:
Book Chapters
Status:
Published
Year Published:
2020
Citation:
Maoz I, Sun P, Haring MA, Schuurink RC, Dudareva N. 2020. Emission and perception of plant volatiles. In E. Pichersky, N. Dudareva (eds), Biology of Plant Volatiles, CRC Press, Taylor and Francis Group, Chapter 14, pp. 251-267.
- Type:
Book Chapters
Status:
Published
Year Published:
2020
Citation:
Lynch JH, Pichersky E, Dudareva N. 2020. Floral scent metabolic pathways and their regulation. In E. Pichersky, N. Dudareva (eds), Biology of Plant Volatiles, CRC Press, Taylor and Francis Group, Chapter 8, pp. 147-164.
- Type:
Book Chapters
Status:
Published
Year Published:
2020
Citation:
Plasmeier M, Liao P, Haring MA, Dudareva N, Schuurink RC. 2020. Molecular engineering of plant volatiles: floral scent, flavors, defense. In E. Pichersky, N. Dudareva (eds), Biology of Plant Volatiles, CRC Press, Taylor and Francis Group, Chapter 20, pp. 379-403.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Investigating the subcellular architecture of the phylloquinone pathway. McCoy RM, Sun B, Herrera K, Widhalm JR. Plant Biology 2020. American Society of Plant Biologists annual meeting. Virtual in 2020
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Investigating resistance mechanisms to the natural product-based herbicide juglone. Meyer GW, Naranjo M, House R, Widhalm JR. Plant Biology 2020. American Society of Plant Biologists annual meeting. Virtual in 2020
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Elucidating the metabolic origin of the geranyl diphosphate moiety of shikonin. Suttiyut T, Auber RP, Ghaste M, Wisecaver JH, Widhalm JR. Plant Biology 2020. American Society of Plant Biologists annual meeting. Virtual in 2020
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Evaluation of a stable isotope-based direct quantification method for dicamba analysis from air and water using single quadrupole LC-MS. Ghaste M, Hayden N, Osterhold MJ, Young J, Young BG, Widhalm JR. Plant Biology 2020. American Society of Plant Biologists annual meeting. Virtual in 2020
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2019
Citation:
Plant natural product biosynthesis and trafficking. Widhalm JR. Chemical Machinery of the Cell Scialog Conference. Tucson, AZ 2019
|
Progress 10/01/18 to 09/30/19
Outputs Target Audience:Research provides a basic knowledge about biosynthesis of plant-produced volatile compounds and their emission into the atmosphere and release of natural products released into the rhizosphere. The work is important for plant biologists, biochemists, atmospheric chemists, and scientists involved in plant metabolic engineering and investigation of plant-plant and plant insect interactions. This research is also of interest for scientists working in floriculture, flavor, cosmetic and fragrance industries, as well as those working to develop novel herbicides and other agricultural products. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Post-doc Dr. Manoj Ghaste has attended training sessions focused on new developments in mass spectrometer technology hosted by Agilent in Indianapolis Graduate student Rachel McCoy attended professional development workshops at the Botany 2019 conference entitled "Using HHMI Videos and Data Points As Tools For Engaging Students From Molecules to Ecosystems" and "Strategies for successful faculty/undergraduate student collaborative research at PUIs." Graduate student Rachel McCoy attended professional development workshops at the Plant Biology 2019 conference entitled "Primarily Undergraduate Institution Faculty Development Workshop," "Being a Plant Biologist in a Primarily Undergraduate Institution," and "How Machine Learning Can Be Used to Solve Plant Biology Problems." Training: This work provided strong multidisciplinary training in plant biochemistry, molecular biology, genetics, in vivo isotopic labeling, GC-MS and LC-MS-based metabolic profiling and integrative modeling for undergraduate and graduate students, as well as post-doctoral scientists. Dr. Joseph Lynch - Post-doc (Purdue University): Analysis of transgenic petunia plants with overexpression of PhCM2 and biochemical interface between Phe and auxin biosynthesis. Yichun Qian - Ph.D. candidate (Purdue University): Generation and metabolic profiling of transgenic petunia plants with overexpression of PhCM2 Pan Liao - Post-doc (Purdue University): Analysis of PhABCG12 downregulation on wax composition and volatile emission. Itay Maoz - Post-doc (Purdue University): Analysis of PhLTP(s) downregulation on volatile emission. Xing-Qi (David) Huang - Post-doc (Purdue University): Identification of transporter involved in shikimate transport out of plastids. Elucidation of benzaldehyde biosynthesis in plants. Shannon Sterling - Graduate Student (Purdue University) Investigation of molecular mechanisms of natural fumigation Dr. Manoj Ghaste - Post-doc (Purdue University): Dicamba volatility research. Rachel McCoy - Ph.D. candidate (Purdue University): Investigation of plant quinone metabolism. Thiti Suttiyut - Ph.D. student (Purdue University): Elucidation of cytoplasmic geranyl diphosphate formation in Lithospermum erythrorhizon George Meyer - Ph.D. student (Purdue University): Investigation of juglone resistance mechanisms in plants Elena Yakubova - Research technician (Purdue University): Determination of quinone content in Impatiens species nectaries. How have the results been disseminated to communities of interest?Invited seminars and invited speaker at meetings: 2019 University Jean Monnet Saint-Etienne, University de Lyon, Saint-Etienne, France, October 14. (Dudareva) 2019 Biochemistry club (for undergraduate students), Department of Biochemistry, Purdue University, October 1. (Dudareva) 2019 XXIII Meeting of the Spanish Society of Plant Physiology and the XVI Hispano-Portuguese Congress of Plant Physiology, Pamplona, Spain, June 26-28. (Dudareva) 2019 2019 Gordon Research Conference on Plant Metabolic Engineering, Lucca (Barga), Italy, June 16-21. (Dudareva) 2019 Institute for Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany, June 3. (Dudareva) 2019 2019 Congress "At the Forefront of Plant Research", Barcelona, Spain, May 6 -8. 2019 2019 Annual Meeting of the American Society for Biochemistry and Molecular Biology (ASBMB), Orlando, FL, April 6-10. (Dudareva) 2019 Friday Seminar at John Innes Center, Norwich, UK, March 15. (Dudareva) 2019 College of Landscape Architecture and Horticulture Sciences, Southwest Forestry University, Kunming, China, February 26. (Dudareva) 2019 School of Landscape Architecture, National Engineering Research Center for Floriculture, Beijing Forestry University, Beijing, China, February 22. (Dudareva) 2019 Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China, February 21. (Dudareva) 2019 Purdue University Botany and Plant Pathology Seminar Series, April 17. (Widhalm) 2018 8th Annual Plant Sciences Symposium, University of Wisconsin - Madison, Madison, WI, (student invited), November 16. (Dudareva) What do you plan to do during the next reporting period to accomplish the goals?We will continue to work on original three objectives of proposed research. Specifically, we will investigate the role of LTPs in volatile emission, and will work on elucidation of molecular mechanisms of natural fumigation.
Impacts What was accomplished under these goals?
Plants synthesize an amazing diversity of volatile organic compounds (VOCs) that are important for reproduction and defense, serve as practical products for humans, and influence atmospheric chemistry and climate. To date, the chemistry of plant volatiles is well understood, however, little is known about the biosynthesis of this diverse group of compounds and their release from the cell to the atmosphere. Phenylpropanoid compounds constitute the second largest class of plant volatiles, which originate from the aromatic amino acid phenylalanine (Phe). In plants Phe is synthesized predominantly via the arogenate pathway in plastids. However, we have recently demonstrated that Phe is also synthesized in the cytosol via the microbial-like phenylpyruvate pathway, which branches from the known plastidial arogenate pathway at chorismate. In contrast to the arogenate pathway, the phenylpyruvate route is subject to less stringent feedback regulation, because cytosolic chorismate mutase 2 (CM2), which catalyzes the initial step in this pathway, is insensitive to allosteric regulation by aromatic amino acids. Thus, we investigated the metabolic consequences of altering carbon flux towards the cytosolic phenylpyruvate pathway in Petunia hybrida flowers, which typically produce high levels of Phe and Phe-derived benzenoid/phenylpropanoid volatiles. Overexpression of PhCM2 in petunia flowers increased flux in cytosolic Phe biosynthesis, but paradoxically decreased the levels of Phe and Phe-derived volatiles. Concomitantly, the levels of auxins, including indole-3-acetic acid and its precursor indole-3-pyruvic acid (IPA), were elevated. A combination of reverse genetics, biochemistry, targeted metabolic profiling, metabolic flux modelling and electron microscopy revealed that (i) overexpression of PhCM2 leads to perturbation of plastid development due to altered auxin metabolism; (ii) this phenotype could be reverted by overexpression of Arabidopsis VAS1, an aminotransferase that converts the auxin IPA back to tryptophan; and (iii) PhTrp-AT, an identified aminotransferase that transaminates tryptophan to auxin, is able to use intermediates/byproducts of the cytosolic Phe biosynthetic pathway as amino acceptors, thereby linking extra-plastidial metabolism of tryptophan and Phe. Overall, our results show the existence of a metabolic crosstalk between the cytosolic Phe pathway and tryptophan-dependent auxin biosynthesis. Despite the relatively low direct contribution of the cytosolic phenylpyruvate pathway to Phe biosynthesis, plants likely use this pathway for rapid production of Phe in response to biotic and abiotic stresses. Thus, the existence of a biochemical interface between Phe and auxin biosynthesis might provide an efficient metabolic mechanism for tissue-specific coordination of stress responses with plant growth and development. Since auxin metabolism intersects through complex networks with the biosynthesis of several other plant hormones, modulation of auxin levels via the cytosolic Phe biosynthetic pathway can have a broader impact on plant growth and development under stress conditions. Plants synthesize volatile organic compounds (VOCs) to attract pollinators and beneficial microorganisms, to defend themselves against herbivores and pathogens and for plant-plant communication. Generally, accumulation and emission of VOCs occur from the tissue of their biosynthesis. However, using biochemical and reverse genetic approaches, we demonstrate a new physiological phenomenon: inter-organ aerial transport of VOCs via natural fumigation. Before petunia flowers open, a tube-specific terpene synthase produces sesquiterpenes, which are released inside the buds and then accumulate in the stigma, potentially defending the developing stigma from pathogens. These VOCs also affect reproductive organ development and seed yield, which is a previously unknown function for terpenoid compounds. Regulation of pistil development by volatile terpenoids from surrounding tube could serve as a mechanism to coordinate the timing of pistil maturation with petal development in order to ensure that the stigma is receptive when the flowers are most likely to attract pollinators. Further studies are required to assess whether natural fumigation is conserved in flowering plants, to uncover the mechanisms involved, and to determine its evolutionary advantage in plant reproduction. While VOCs also play important roles belowground, so do plant exudates released from roots containing non-volatile compounds. Unlike VOCs, however, the roles that these compounds play in mediating plant-biotic interactions is poorly understood. Moreover, little is known about biosynthesis of these compounds and the mechanisms responsible for their release from the cell into the rhizosphere. Specialized 1,4-naphthoquinones (1,4-NQ) have emerged as a major class of compounds involved in belowground plant-biotic interactions. Plants collectively synthesize hundreds of 1,4-NQs proposed to play roles in various plant-plant, plant-microbe and plant-animal interactions. Based on developments in understanding of plant metabolic networks, reinterpretations of classical tracer studies suggest that 1,4-NQs are synthesized through several routes. We hypothesize that these routes rely on precursors from four different primary metabolic sources. Recently, we used comparative transcriptomics and isotopic labeling to demonstrate that the 1,4-NQ moiety of juglone, the 1,4-NQ responsible for the allelopathic effects of black walnut (Juglans nigra) trees, is derived from the pathway responsible for producing the naphthalenoid moiety of phylloquinone. We also showed that juglone can be synthesized de novo in roots without translocation of precursors from the phylloquinone pathway present in aerial tissues. These results demonstrate indeed that the pathway to synthesize juglone, and likely other structurally similar 1,4-NQs produced from black walnut trees and other members of the Juglandaceae family, branches from primary quinone metabolism. This provides direct evidence for the connection between primary and specialized quinone metabolism, which may help guide elucidation of the metabolic origins of other 1,4-NQs in other plants. In addition to belowground roles, the occurrence of specialized 1,4-NQs in aerial tissues suggests that they have additional ecological roles aboveground and/or that the mechanisms for their deployment into the rhizosphere rely on tissues/organs present on the aerial portion of the plant. Therefore, we investigated whether 1,4-NQs present in Impatiens glandulifera flowers play a role in influencing the growth of nectar microbes, a mechanism we hypothesized is analogous to the role of structurally similar compounds in the pitcher fluid of carnivorous Nepenthes species. After systematic profiling of 1,4-NQs in different Impatiens organs, we found that the compounds are present in all parts of the plant, including floral nectaries. We also found that the two major compounds present in nectaries, lawsone and 2-methoxynaphthoquinone, exhibit antimicrobial activity against common nectar microbes. In addition to 1,4-NQs being detected in floral nectaries, they were found to be present in higher abundance in extra-floral nectaries. The nectar excreted by these organs, which are connected to vegetative tissues, is hypothesized to attract beneficial insects and other animal mutalists. Analysis of the nectar itself collected from extra-floral nectaries revealed high concentrations of 1,4-NQs. This leads us to hypothesize that broadly throughout plants, natural products are secreted into the nectar that gets released by extra-floral nectaries. This would then allow extra-floral nectaries to play an additional unsuspected role as a conduit to deploy non-volatile compounds from aerial tissues into the rhizosphere via nectar that is washed into the ground through rainfall.
Publications
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2019
Citation:
Allelopathy as an evolutionarily stable strategy. McCoy RM, Widhalm JR, McNickle GG. Botany 2019. July 2019, Tucson AZ.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2019
Citation:
Using synthetic biology to investigate the subcellular architecture of the phylloquinone pathway. McCoy RM and Widhalm JR. Plant Biology 2019, August 3-7, San Jose CA.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Yahyaa M, Berim A, Nawade B, Ibdah M, Dudareva N, Ibdah M. 2019. Biosynthesis of methyleugenol and methylisoeugenol in Daucus carota leaves: Characterization of eugenol/isoeugenol synthase and O-methyltransferase. Phytochemistry, 159: 179-189.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Zhao D, Hamilton JP, Bhat WW, Johnson SR, Godden GT, Kinser TJ, Boachon B, Dudareva N, Soltis DE, Soltis PS, Hamberger B, Buell CR. 2019. A chromosomal-scale genome assembly of Tectona grandis reveals the importance of tandem gene duplication and enables discovery of genes in natural product biosynthetic pathways. GigaScience, 8, 1-10.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Johnson SR, Bhat WW, Bibik J, Turmo A, Hamberger B, Evolutionary Mint Genomics Consortium (Dudareva N. et al.), Hamberger B. 2019. A database-driven approach identifies additional diterpene synthase activities in the mint family (Lamiaceae). J. Biol. Chem., 294: 1349-1362.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
McCoy RM, Utturkar S, Crook JW, Thimmapuram J, and Widhalm JR. 2018. The origin and biosynthesis of the naphthalenoid moiety of juglone in black walnut. Horticulture Research, 5:67.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Block AK, Yakubova E, and Widhalm JR. (2019) Specialized naphthoquinones present in Impatiens glandulifera nectaries inhibit the growth of fungal nectar microbes. Plant Direct, 3:1-7.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Smith SD, Angelovici R, Heyduk K, Maeda HA, Moghe GD, Pires JC, Widhalm JR, and Wisecaver JH. (2019) The renaissance of comparative biochemistry. American Journal of Botany, 106(1):1-11.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2019
Citation:
Epigenetic modifications are essential for the rhythmic control of volatile organic compound emission in Petunia hybrida. Stirling S, Patrick R, Lynch J, Mensah I, Li Y, Dudareva N. 2019 ASPB Midwest Conference, March 16, 2019, Morgantown, West Virginia.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2019
Citation:
Natural fumigation as a mechanism for volatile transport between flower organs. Lynch JH, Boachon B, Ray S, Yuan J, Morgan JA, Dudareva N. 2019. Gordon Research Conference on Plant Metabolic Engineering, June 16-21, Lucca (Barga), Italy.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2019
Citation:
Using synthetic biology to investigate the subcellular architecture of the phylloquinone pathway. McCoy RM and Widhalm JR. Plant Synthetic Biology 2019, August 8-10, San Jose CA.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2019
Citation:
The Effects of Adjuvants and Carrier Water Characteristics on Dicamba Volatilization in a Controlled Environment. Hayden C, Young JM, Ghaste MS, Johnson WG, Widhalm JR, Young BG. North Central Weed Science Society Conference 2019.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2019
Citation:
Gene co-expression network analysis identifies gene candidates for shikonin biosynthesis pathway in the medicinal plant Lithospermum erythrorhizon. Auber R, Suttiyut T, Crook JW, Widhalm JR, Wisecaver J. SMBE 2019 (Society for Molecular Biology and Evolution). Manchester, UK.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Plant natural product biosynthesis and trafficking. Widhalm JR. 2018 Chemical Machinery of the Cell Scialog Conference. October 2018, Tucson, AZ.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Jantzen F, Lynch JH, Kappel C, H�fflin J, Skaliter O, Wozniak N, Sicard A, Sas C, Adebesin F, Ravid J, Vainstein A, Hilker M, Dudareva N, Lenhard M. 2019. Retracing the molecular basis and evolutionary history of the loss of benzaldehyde emission in the genus Capsella. New Phytologist, 224: 1349-1360.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Boachon B, Lynch JH, Ray S, Yuan J, Caldo KMP, Junker RR, Kessler SA, Morgan JA, Dudareva N. 2019. Natural fumigation as a mechanism for volatile transport between flower organs. Nature Chem. Biol., 15: 583-588 (Cover, highlighted in Research Highlights, Nature Plants 2019, 5: 644).
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Qian Y, Lynch JH, Guo L, Rhodes D, Morgan JA, Dudareva N. 2019. Completion of the cytosolic post-chorismate phenylalanine biosynthetic pathway in plants. Nature Communications, 10: 15; doi: 10.1038/s41467-018-07969-2.
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