PI: Frank White (Kansas State University) Co-PIs: Adam Bogdanove (Cornell University), Bing Yang (Iowa State University), and Volker Brendel (Indiana University)
Rice, a major food source for the world population, presents an excellent opportunity for in-depth analyses of the adaptive processes of plant disease susceptibility. In particular, the two groups of bacteria within the species Xanthomonas oryzae are the causal agents of bacterial blight and bacterial leaf streak diseases of rice. The bacteria cause disease, in part, modulating host gene expression utilizing a remarkable repertoire of transcription activation-like (TAL) effectors. TAL effectors are proteins synthesized in bacteria and transferred to plant cells during the infection process. The host transcriptional responses to TAL effector attack are complex, and unraveling of the transcriptional "shock" due to the large repertoire of TAL effectors injected into the host cells behooves a more detailed understanding of host gene response to individual TAL effectors. At the same time, other disease complexes that involve large repertoires of TAL effectors in the respective pathogen, and additional disease complexes will be profiled. This project will characterize the host gene expression responses to infection by Xanthomonas pathogens of rice, wheat, cotton, soybeans, and alfalfa using high through-put nucleic acid sequencing technologies. The role played by select host genes whose expression is found to be highly up-regulated in response to specific TAL effectors will be analyzed using advanced gene targeting technologies. TAL effectors function by binding to sequences in the host genome that direct the expression of individual genes, which are known as promoters. The project will also develop refined bioinformatic tools derived from shared features of promoters that are targeted by specific TAL effectors. This information will improve our insight into the vulnerabilities of plants to transcriptional shock and greatly further our ability to predict TAL effector target sites in a genome and to effectively design custom TAL effectors for targeted gene manipulation.
This project will elucidate the processes in rice susceptibility and resistance to bacterial blight and bacterial leaf streak, and establish important, broadly relevant concepts of plant-pathogen interactions and TAL effector biotechnology. The results will provide insight into strategies for achieving durable and broad resistance against disease, which, in itself, can have wide-reaching impacts on the environment and quality of life. The research will enhance the educational environments at ISU, KSU, Cornell, and IU and strengthen international collaborative research. Research activities will be integrated with education and outreach by mentoring graduate student and postdocs, providing internships for under-represented undergraduate students, and providing research experiences to high school students and teachers. Workshops will be conducted that will be open to interested national and international students and researchers in the field. The public will have access to the data at various public databases including the Gene Expression Omnibus (GEO) database at NCBI. Links to data, publications and repositories will also be available at a project website at Gramene.
