** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** PLANT-COLONIZING BENEFICIAL BACTERIA HAVE LONG BEEN HARNESSED TO BOOST THE PRODUCTIVITY AND RESILIENCE OF CROPS, AND BACTERIAL CROP TREATMENTS REPRESENT A RAPIDLY GROWING INDUSTRY IN THE US. THE BENEFIT OF THESE BACTERIA CAN BE LIMITED BY UNPREDICTABLE SURVIVAL IN THE ENVIRONMENT, WHERE PREDATORS, INCLUDING SINGLE-CELLED MICROBES KNOWN AS PROTISTS, ARE A MAJOR CAUSE OF BACTERIAL DEATH. SOME PLANT BENEFICIAL BACTERIA CAN DEFEND THEMSELVES AGAINST PROTIST ATTACK, AND PROTISTS MAY HELP THESE GROUPS OF BACTERIA THRIVE AND BECOME MORE EFFECTIVE IN PROMOTING PLANT GROWTH. HOWEVER, NOT MUCH IS KNOWN ABOUT WHICH TYPES OF BACTERIA BENEFIT MOST FROM THE PRESENCE OF PROTISTS ON THE PLANT, OR THE STRATEGIES THEY USE TO SURVIVE. IN THIS PROJECT, WE WILL USE DNA SEQUENCING TECHNIQUES TO IDENTIFY WHICH BACTERIA FROM PLANTS AND SOILS ARE ENRICHED BY DIFFERENT TYPES OF PROTISTS, AND TO UNDERSTAND WHICH BACTERIAL GENES AND FUNCTIONS ARE USED IN COOPERATING WITH OR DEFENDING AGAINST PROTISTS. WE WILL ALSO STUDY WHETHER BACTERIA AND PROTISTS HELP EACH OTHER COLONIZE PLANT ROOTS, AND HOW THEIR INTERACTIONS AFFECT PLANT GROWTH AND HEALTH. BY HELPING RESEARCHERS UNDERSTAND HOW PROTIST INTERACTIONS AFFECT THE SUCCESS OF BENEFICIAL BACTERIA, THIS RESEARCH COULD ONE DAY BE APPLIED TOWARD PROTIST-INFORMED SCREENING OR DESIGN OF IMPROVED MICROBIAL COMMUNITIES.?