Progress 03/01/10 to 02/28/13
Outputs
Target Audience: The principal target audiences are scientists engaged in research in agriculture, entomology, plant-insect interactions, plant biology,and host plant resistance. The identification of the genetic basis for plant resistance (e.g., inducible trichomes) and non-genetic based (transgenerational and epigenetic) to Helicoverpa zea will provide additonal tools for plant breeders and those agricultural professional using seed treatments to manage isnect pests. Because treatment or the maternal parent or the seed with jasmonic acid elicits long lasting resistance in the offspring provides a new tool for using seed treatments. The findings and implication of the research has been presented in several venues including the classroom in a graduate level course and to several K-12 presentations by participants in the project. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Several graduate students have participated in various aspects of this project including Donglan Tian (Ph.D. graduate who is now employed as a project scientist with Agraquest Davis Ca.), Jinwon Kim (Ph.D. graduate now employed as a postdoc at the University of Neuchatel, Switzerland), and Flor Edith Acevado (current Ph.D.candidate in Entomology). Additionally one visiting student from China (Shuang Wu) completed part of her Ph.D. research in our laboratories. Dr. Fang Liu is a visiting Associate Professor from China and is engaged on several aspects of this project. How have the results been disseminated to communities of interest? Gene sequences have been deposited in NCBI GenBank and several more will be deposited when final aspects of this project are pubolished. Results from this work have been presented at several meetings of U.S.professional societies (Entomological Society of America, American Society of Plant Biologists), International meetings (IOBC; International Symposium on the Insect Midgut), government agencies (Taiwanese Agricultural Research Institute,Taichun, Taiwan)and at several universities nationally (e.g., Texas A&M, University of North Texas, etc.) and internationally (Taiwan National University, National Chung Hsing University). What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Essentially all goals of this research project were accomplished and have been published. Several additional papers will be submitted this year from work completed under this project. The project focused on identifying salivary proteins in Helicoverpa zea that may mediate induced plant responses. A summary of the accomplishements for each objective follow: Objective 1: A major finding of the project is that saliva (and specifically glucose oxidase) not only mediates the induction of rapid responses (e.g., jasmonic acid biosynthesis and defense genes/proteins), but also causes a delayed response in the induction of glandular trichomes in newly formed leaves. This response not only persists for several weeks, but the offspring of plants suffering herbivory also show a heightened or primed defense in the next generation. This transgenerational response depends upon jasmonic acid biosynthesis and the production of small RNAs. Glandular trichomes were shown to play an important role in defense/resistance against Helicoverpa zea, but surprisingly the presence of high densities of non-glandular trichomes was associated with increased susceptibility. Objective 2:We analyzed the plasticity in salivary gene expression in response to several dietary regimens including dietary jasmonic acid, induced tomato plants, tomato plants deficient in jasmonate biosynthesis, etc. The major finding as analyzed by multivariate analyses is that a significant up regulation of salivary genes occurs in response to feeding on induced tomato plants. The major salivary genes responding to this treatment include a salivary trypsin and chymotrypsin, both of which were found to be insensitive to proteinase inhibitors. Thsi indicates that an important counteradaptation to plant defense occurs in the salivary secretome of this insect. Objective 3: Among the salivary proteins identified by proteomic analyses, Glucose oxidase was found to comprise nearly 33% of the identified salivary proteins in Helicoverpa zea. Moreover glucose oxidase occurs very broadly among caterpillar species and is associated with a broad host range among generalist species. In addition to glucose oxidase, four salivary proteins were cloned, sequenced, and expressed in E.coli. The expressed proteins (including several with ATPase activities and a protein tyrosine phosphatase= PTP) were shown to suppress bothrapid and delayed induced responses. These findings are of particular interest becuase they indicate that disruption of plant extracellular ATP signaling by the herbivore downregulates the expression of induced defense. The expression and secretion of PTP indicates that the herbivore may be manipulating MAP kinase signaling which occurs upstream of jasmanate signaling. Findings to date indicate that saliva contains both herbivore-associated molecular patterns (or HAMPs) that induce defenses and effectors that suppress induced responses. The synthesis of the findings demonstrate that the impact of saliva depends upon the specific host plant and the relative balance between salivary HAMPs and effectors.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Louis J, Peiffer M, Ray S, Luthe DS, Felton GW (2013) Host-specific salivary elicitor(s) of European corn borer induce defenses in tomato and maize. New Phytologist doi:10.1111/nph.12308
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Wu S, Peiffer M, Luthe DS, Felton GW (2012) ATP hydrolyzing salivary enzymes of caterpillars suppress plant defenses. Plos One 7 (7):e41947.
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Kim J, Felton GW (2012) Priming of antiherbivore defensive responses in plants. Insect Science
- Type:
Book Chapters
Status:
Awaiting Publication
Year Published:
2013
Citation:
Felton, G.W. Chung S.H., Estrada Hernandez, M.G., Louis, J., Peiffer, M. and Tian, D. 2013. Chapter 2: Herbivore oral secretions are the first line of protection against plant induced defenses. IN: Annual Plant Reviews: Plant-Insect Interactions. Voelckel, C and Jander, G. (editors).
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Progress 03/01/11 to 02/28/12
Outputs
OUTPUTS: Experiments were conducted and analyzed by graduate students, a visiting scholar, and a lab research associate. The project has involved mentoring and training of 3 graduate students and a visiting Ph.D. student from China. New lab techniques were developed in protein chemistry, proteomics, and E.coli. based protein expression. The results of the findings have been disseminated broadly in a review article (in press) and at scientific meetings on campus, nationally and internationally. Presentation of research on caterpillar saliva was presented at the Annual meeting of the Entomological Society of America (invited), the International Society of Chemical Ecology, the University of California, Davis (invited) and at several venues on the campus of Penn State University. Salivary genes that have been cloned and sequenced were been uploaded to Gene Bank and have been sued by other investigators working on salivary genes/proteins. PARTICIPANTS: In addition to the PDs, the most signciant participants and contributors on the project have included doctoral students, Donglan Tian and Shuang Wu who conducted the majority of the experiments, cloned and sequenced salivary genes. Donglan Tian will complete her Ph.D. this summer and Shuang Wu, who was a visiting student from China, has completed her Ph.D. in China. Michelle Peiffer, research associate, has been responsible for collection and proteomic analysis of saliva. She has also developed refined methods for the collection of saliva to obtain sufficient quantities for analysis. Collaboration with John Tooker at Penn State has aided in the analysis of plant hormones and plant volatiles. International collaborations with Eric Haubruge and Frederic Francis have involved proteomic analyses of caterpillar secretions. TARGET AUDIENCES: The principal target audience is scientists engaged in research in plant-insect interactions and host plant resistance. The identification of the genetic basis for plant resistance (e.g., inducible trichomes) and non-genetic based (transgenerational and epigenetic) resistance to Helicoverpa zea will provide additonal tools for plant breeders and those agricultural professionals using seed treatments to manage isnect pests. Because treatment or the maternal parent or the seed with jasmonic acid elicits long lasting resistance in the offspring provides a new tool for using seed treatments. The findings and implications of the research have been presented in several venues including the classroom in a graduate level course and to several K-12 presentations by participants in the project. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The project has focused on identification of salivary proteins in Helicoverpa zea that may mediate plant responses. One of the major findings of the project is that saliva (and specifically glucose oxicdase) not only mediates the induction of rapid responses (e.g., jasmonic acid biosynthesis and defense genes/proteins), but also causes a delayed response in the induction of glandular trichomes in newly formed leaves. This response not only persists for several weeks, but the offspring of plants suffering herbivory also show a heightened or primed defense in the next generation. This transgenerational response depends upon jasmonic acid biosynthesis and the production of small RNAs. Glandular trichomes were shown to play an important role in defense/resistance against Helicoverpa zea, but surprisingly the presence of high densities of non-glandular trichomes was associated with increased susceptibility. Glucose oxidase was found to comprise nearly 33% of the identified salivary proteins in Helicoverpa zea. Moreover glucose oxidase occurs very broadly among caterpillar species and is assocaited with a broad host range among generalist species. In addition to glucose oxidase, four salivary proteins were cloned, sequenced, and expressed in E.coli. The expressed proteins (including several with ATPase activities and a protein tyrosine phosphatase) were shown to suppress both rapid and delayed induced responses. Findings to date indicate that saliva contains both herbivore-associated molecular patterns (or HAMPs)that induce defenses and effectors that suppress induced responses. The synthesis of the findings demonstrate that the impact of saliva depends upon the specific host plant and the relative balance between salivary HAMPs and effectors.
Publications
- Rasmann, S., M. De Vos, C. L. Casteel, D. Tian, R. Halitschke, J. Y. Sun, A. A. Agrawal, G. W. Felton, and G. Jander. 2012. Herbivory in the previous generation primes plants for enhanced insect resistance. Plant Physiology 158, 854-863.
- Tian, D., M. Peiffer, E. Shoemaker, J. Tooker, E. Haubruge, F. Francis, D. S. Luthe, and G. W. Felton. 2012. Salivary Glucose Oxidase from Caterpillars Mediates the Induction of Rapid and Delayed-Induced Defenses in the Tomato Plant. PLoS One dx.plos.org/10.1371/journal.pone.0036168.
- Tiam, D., J. Tooker, M. Peiffer, S. H. Chung, and G. W. Felton. 2012. Role of trichomes in defense against herbivores: comparison of herbivore response to woolly and hairless trichome mutants in tomato (Solanum lycopersicum). Planta http://dx.doi.org/10.1007/s00425012-16519.
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Progress 03/01/10 to 02/28/11
Outputs
OUTPUTS: The results have been disseminated through presentations at the Mid-Atlantic Plant Molecualar Biology Society, Insect Chemical Ecology Workshop, In Vitro Biology National Meeting, Entomological Society of America, and International Society of Plant Molecular Biology. Gene sequences have been deposited through NCBI for several salivary genes including: glucose oxidase ACJ71598.1 ecdysone oxidase ACL36977.1 ATP synthase ADJ95799.1 Apyrase ADK90114.1 Protein Tyrosine Phosphatase ADP20217.1 ATPase ADN88179.1 PARTICIPANTS: Donglan Tian (Ph.D. student), Jinwon Kim (Ph.D. student), Helene Quagehbeur (Ph.D. student), Michelle Peiffer (Lab Manager), Frederic Francis (collaborator, Gembloux University), and Eric Haubruge (collaborator, Gembloux University). TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Our specific objectives are to: 1/Characterize salivary components involved in elicitation of induced defenses in tomato. 2/ Characterize plasticity in salivary gene expression. 3/ Conduct functional analyses of selected salivary genes. We have completed experiments demonstrating that glucose oxidase is an elicitor of defenses in tomato. As a result of ongoing proteomic analyses we have identified salivary amylase and fructosidase as complementary enzymes that enhance the eliciting activity of glucose oxidase. As part of these analyses we have identified another suite of salivary proteins (ATPase, apyrase, ATP synthase, tyrosine phosphatase) that all may play a role in mediating plant defense signaling. These four proteins have been expressed in E.coli and we are currently conducting functional analyses of their activity. We have completed experiments on diet effects on salivary gene plasticity which has helped identify several additional salivary elicitors. Our findings may reveal additional targets for informing decisions on the use of plant resistance against insects.
Publications
- Eichenseer, H., M. C. Mathews, J. S. Powell, and G. W. Felton. 2010. Survey of a salivary effector in caterpillars: glucose oxidase variation and correlation with host range. J Chem Ecol 36:885-897
- Kim, J., H. Quagehbeur, and G. W. Felton. 2011. Reiterative and Interruptive Signaling in Induced Plant Resistance to Chewing Insects. Phytochemistry (In Press)
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