Functions of Conserved Oomycete Effector Proteins

Virginia Polytechnic Institute And State University, Blacksburg VA

Investigators

Abstract

Oomycete plant pathogens cause extremely destructive diseases on crops and in natural ecosystems. Little is known about the molecular weapons that enable oomycetes to be such successful pathogens. Analyses of four recently completed oomycete genomes suggest that oomycetes export dozens or hundreds of their own 'effector' proteins to the interior of plant cells. These pathogen effectors are expected to sabotage plant immune responses and trigger other effects that benefit the pathogen. However, almost nothing is known about the molecular functions of oomycete effectors. This project will investigate the functions of six pairs of effectors that are conserved between two distantly related oomycetes: the Arabidopsis downy mildew pathogen Hyaloperonospora parasitica and the soybean root rot pathogen Phytophthora sojae. It is expected that a focus on conserved effectors will reveal insights that are applicable to the majority of oomycete pathogens. The investigators will perform a series of molecular genetic experiments to determine whether these effectors are capable of suppressing plant immunity or altering plant cell structure or physiology, and whether the pathogen's ability to cause disease is affected when these genes are silenced or overexpressed. Finally, one pair of conserved proteins will be selected for experiments to identify their exact targets inside plant cells. These experiments are expected to reveal important, broadly conserved molecular strategies that underpin oomycetes' ability to cause disease, which will in turn open new avenues toward more sophisticated disease control strategies. The project will provide multidisciplinary training for graduate students and undergraduates. Some aspects of the project will be collaboratively integrated with an outreach program at Virginia Tech that uses Arabidopsis reverse genetics in high school science classrooms.