Grant: Discovery Grants Program - Individual

Research Program Context: Disease tolerance is a defense strategy used by host plants to grow and produce equitable yield without displaying severe symptoms despite being infected by a pathogen. Lipids (membrane and oxylipins) are among the first defense compounds produced or remodeled in response to infection in several host pathogen relationships. How lipid mediated plant immunity converge to confer tolerance in these pathosystems is unknown. There are over 200 oxylipins that form part of the plant defense strategy, serving as signal molecules to induce defense responses, or function directly as antimicrobial compounds. Membrane lipids and oxylipins can form part of the plant defense strategy, serving as signal molecules to induce defense responses, or function directly as antimicrobial compounds. These modes of actions indicate oxylipins and/ or membrane lipids could be potent biochemical sources of novel disease tolerance in specific host pathogen relationships such as the soybean Phytophthora sojae (P.sojae) pathosystem Problem statement: Root and stem rot caused by P.sojae account for over $2B USD annually in global soybean crop losses. Disease management strategy currently seeks new sources of durable resistance to protect against crop losses. Preliminary work by our research group suggests that tolerant soybean cultivars rapidly modulate both membrane lipids and oxylipins metabolism as part of a successful strategy to limit P.sojae infection.  Long term goal: To understand the lipid mediated mechanisms underlying successful disease tolerance or virulence in the soybean¬ P. sojae pathosystem. Short term objectives: 1) To develop a P.sojae and soybean lipid metabolic map using a systems biology approach to understand plant oxylipin induction and membrane lipid metabolism in response to host colonization and infection. 2) To determine the spatial metabolism of plant and pathogen derived membrane lipids and/or oxylipins to disease tolerance or pathogenicity. 3) To assess the phytoprotective, antimicrobial or virulence effects of membrane lipids and oxylipins during pathogenesis. Methodology: Test cup and zoospore inoculation methods will be used along with chromatographic, lipid imaging, advanced lipid bioinformatics, vibrational spectroscopic and mass spectrometric techniques to determine how oxylipin and membrane lipid metabolism mediate P.sojae infection or virulence in susceptible and tolerant soybean cultivars.   Significance:  The outcomes of this study findings will be used to develop novel lipid mediated biochemical sources of tolerance to improve the innate resistance of soybeans to root and stem rot caused by P. sojae. Development of increased P. sojae tolerance in soybeans will be an effective long term crop protection strategy beneficial in reducing billions of dollars in soybean yield losses globally to P. sojae infection as well as provide a long-term strategy for durable crop tolerance dependent on quantitative resistance.