** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** UNDERSTANDING AGRICULTURAL MICROBIAL COMMUNITIES HAS THE POTENTIAL TO TRANSFORM AGRICULTURAL PRODUCTION SYSTEMS, HUMAN WELL-BEING, AND ENVIRONMENTAL HEALTH. ALTHOUGH SIGNIFICANT EFFORTS HAVE BEEN MADE TO UNDERSTAND THE PROCESSES THAT DETERMINE MICROBIOME STRUCTURE AND ACTIVITY, THERE REMAIN CONSIDERABLE HURDLES TO ACHIEVING DIRECTED MICROBIOME MANIPULATION IN AN AGRICULTURAL SETTING. WE AIM TO DEVELOP A MECHANISTIC UNDERSTANDING OF THE MICROBIOME ASSOCIATED WITH MUSHROOM DEVELOPMENT, WHICH WE TERM THE MUSHROOM DEVOME (DEVELOPMENTAL MICROBIOME), AS WELL AS DISEASE SUPPRESSION. PRELIMINARY RESEARCH FROM OUR GROUP HAS DEMONSTRATED THAT USING EITHER ANTIBIOTICS OR SERIAL PASSAGING, WE WERE ABLE TO MODIFY THE MUSHROOM SUBSTRATE MICROBIOME IN A WAY THAT AFFECTS THE TIMING OF MUSHROOM DEVELOPMENT, AMOUNT OF HARVESTED MUSHROOM CAPS, AS WELL AS DISEASE SUPPRESSION TOWARD BACTERIAL BLOTCH AND GREEN MOLD. WE WILL TAKE ADVANTAGE OF THE ONE-OF-ITS-KIND PENN STATE MUSHROOM RESEARCH CENTER FACILITY TO CONDUCT THIS GROUNDBREAKING RESEARCH THAT WILL RESULT IN A DEEPER UNDERSTANDING OF THE MICROBIAL MEMBERS AND PROCESSES THAT DRIVE MUSHROOM DEVELOPMENT, WITH A POTENTIAL FOR PRODUCING MORE SUSTAINABLE AGRICULTURAL OUTPUT.