ELUCIDATING MICROBIAL-MEDIATED MECHANISMS OF SOIL-BORNE DISEASE SUPPRESSION

Soil-borne plant pathogens are major yield-limiting factors in the production of food, fiber, and ornamental crops. These pathogens are difficult to control by conventional strategies due to their often-rapid development of chemical resistance and the lack of disease-resistant cultivars. Recently, my lab has implemented a strategy to steer soil-borne disease suppressiveness against the fungal pathogen Verticillium dahlia race 1 via soil and plant-rhizosphere microbiome manipulation. This research proposal aims to extend this work toward elucidating the organisms and microbial-mediated mechanisms associated with V. dahlia control in distinct disease-suppressive soils. Briefly, aim 1 will leverage an existing resource of disease-suppressive and conducive (i.e., non-suppressive) soils to identify the set of microbial taxa and functions associated with V. dahlia control (using amplicon sequencing and metagenomics). Aim 2 will test a representative collection of bacterial isolates obtained from these suppressive soils for their potential to control V. dahlia growth in vitro via two distinct mechanisms (i.e., the production of exometabolites or volatile compounds). Finally, aim 3 will explore the resilience of these disease-suppressive soils once exposed to two common agricultural disturbances (i.e., herbicide application and soil acidification). This project aligns with the program goals by (i) advancing the characterization of molecular mechanisms associated with disease suppression, and (ii) elucidating the composition and function of microbiomes conferring specific host phenotypes (in this case, plant protection). This project has great potential to inform the development of novel strategies for controlling soil-borne pathogens while minimizing environmental impacts and promoting sustainability in agroecosystems.