PLANT-ASSOCIATED MICROORGANISMS PLAY VITAL ROLES IN HOST PHENOTYPE AND FITNESS, AND HAVE STRONG POTENTIAL TO BE HARNESSED FOR SUSTAINABLE AGRICULTURE. HOWEVER, DESPITE GROWING INTEREST IN INTEGRATING BENEFICIAL MICROORGANISMS INTO AGRICULTURAL PRACTICES, IT IS UNCLEAR HOW INTERACTIONS BETWEEN PLANT SYMBIONTS AFFECT THEIR SHARED HOST. THIS PROJECT WILL INVESTIGATE HOW ABOVEGROUND AND BELOWGROUND PLANT SYMBIONTS MODIFY EACH OTHER, AND AFFECT HOST DEFENSE AND PRODUCTIVITY. SPECIFICALLY, WE WILL USE SOYBEAN (GLYCINE MAX) TO STUDY HOW SOYBEAN'S CHARACTERISTIC RHIZOBIA INTERACT WITH FOLIAR ENDOPHYTIC FUNGI, MICROBIOTA OF LEAVES. MULTIPLE BENEFICIAL PLANT SYMBIONTS INTERACTING VIA A SHARED HOST MAY HAVE POSITIVE SYNERGISTIC EFFECTS, SO UNDERSTANDING AND EMPLOYING THESE INTERACTIONS IS A PROMISING AVENUE FOR SUSTAINABLE AGRICULTURE. OUR RESEARCH WILL FOCUS ON UNDERSTANDING HOW PLANT-ASSOCIATED MICROORGANISMS INTERACT TO AFFECT PLANT HEALTH AND PRODUCTIVITY IN SOYBEAN, AND WILL INFORM GENERAL IMPLEMENTATION OF MULTIPLE MUTUALIST EFFECTS AS A SUSTAINABLE AGRICULTURAL TECHNIQUE FOR INCREASED YIELD AND BIOCONTROL.