Molecular Basis of Disease: The role of the type III effector PthXo6 During Bacterial Colonization of Rice

Kansas State University, Manhattan KS

Investigators

Abstract

The mechanisms underlying the plant disease susceptibility by bacterial pathogens are largely unknown. Evidence has shown that some bacterial proteins are injected into plant cells through a type III secretion apparatus and play an essential role in disease physiology along with their corresponding host factors. This investigation will study the molecular mechanism underlying the bacterial pathogenesis governed by such a type III effector protein (PthXo6) of Xanthomonas oryzae pv. oryzae and its corresponding rice host genes. The work will test the hypothesis that PthXo6-dependent induction of TFX1, a transcription factor gene of the bZIP family, and subsequent activity of TFX1 protein, facilitates bacterial colonization and early disease development. Molecular, genomics and biochemical techniques will be coupled with rice transformation and transgenic analysis to define the molecular mechanisms underlying the disease susceptibility of rice bacterial blight as mediated by PthXo6 and TFX1. The specific objectives are: (1) identify rice genes modulated by PthXo6 or downstream genes regulated through the activation of TFX1 by microarray analysis; and (2) analyze the selected host genes obtained from Objective 1 for causative effects on disease susceptibility. This study will shed light on the first characterized target of type III virulence factors as they function in mediating susceptibility, and also provide insight into new strategies for crop protection and the process of the evolutionary adaptations in the host and pathogen populations. The results of the study will have broad impact on knowledge of plants and their pathogens and the educational environment at KSU and internationally. Projects in the PI's laboratory has a strong involvement by undergraduate students, including participation in research and supplemental coursework. This project will result in training and education of graduate students in the aforementioned technologies and providing undergraduates with hands-on experience in the latest powerful tools of genomic and protein analyses in laboratory.