Transcription Profiling and Functional Analyses of Bacterial Disease Susceptibility Pathways of Rice

Kansas State University, Manhattan KS

Investigators

Abstract

PI: Frank White, Kansas State University Co-PI: Adam Bogdanove, Iowa State University Co-PI: Bing Yang, Iowa State University Collaborator: Dan Nettleton, Iowa State University Rice, the major food source for a large portion of the world population, is a premier species for genome-enabled crop research. The interactions of rice and associated pathogens are an important topic and an excellent opportunity for in-depth analyses of the adaptive processes of plant disease susceptibility and defense. The two pathovars of Xanthomonas oryzae, the causal agents of bacterial blight and leaf streak of rice, cause disease in part by modulating host plant gene expression. Global changes in rice gene expression will be characterized during the disease process and during successful defense responses to identify the host genes that control host susceptibility and resistance (R) to bacterial infection. Additionally, since pathogen populations have evolved over time in response to new genetic mechanisms of resistance in the host, the project will characterize the diversity of adaptations based on host responses to infection by different pathogen strains. Mutant rice lines and manipulation of host gene expression by inhibitory RNA (RNAi) will be employed to determine the functional significance of selected candidate host genes involved in disease and defense responses. The project will carry out (1) profiling of host transcriptional responses in rice cultivar Nipponbare, as well as other diverse host genotypes (domestic rice and wild relatives) to three sequenced strains of the pathogens using microarray gene chip hybridization and quantitative, real time, reverse transcriptase polymerase chain reaction methods; (2) profiling of responses of a set of rice lines near-isogenic for either recessive or dominant R genes to define pathways for susceptibility and induced innate immunity; and 3) functional analyses of candidate host susceptibility and defense genes and associated gene families using gene transfer, RNAi, and mutagenesis techniques. Array data will be deposited to PlexDB (http://www.plexdb.org/)and other project outcomes will be available through http://www.oznet.ksu.edu/plantpath/whiteslab/welcome.htm. 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. 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 work will enhance the educational environments at Iowa State University and Kansas State University and strengthen international collaborative research. The participating research programs will foster the participation of scientists at all levels of education and internationally. Each of the investigators contributes strongly to research programs for both resident and visiting undergraduate students, including the Summer Research Opportunities Program (SUROP) at Kansas state University, REU and RET programs at Iowa State University, and individually tailored research and supplemental coursework. Workshops will be conducted including members of all labs and interested national and international students and researchers in the field.