THE ONGOING AND MAGNIFYING CONSEQUENCES OF ENVIRONMENTAL CHANGE PRESENT A COMPLEX, URGENT CHALLENGE FOR PLANTS. ONE POTENTIAL MECHANISM BY WHICH PLANTS MAY PROMOTE LONG-TERM STRESS TOLERANCE IS VIA SELECTION OF BENEFICIAL MEMBERS OF THE SEED MICROBIOME. OUR GOAL IS TO UNDERSTAND THE IMPACT OF ABIOTIC STRESS ON THE INHERITED SEED MICROBIOME; THE MECHANISMS BY WHICH THE SEED MICROBIOME MEMBERS, THE PLANT, AND THE ENVIRONMENT INTERACT; AND ITS IMPLICATIONS FOR THE RESILIENCE OF SUBSEQUENT PLANT GENERATIONS. WE WILL USE COMMON BEAN (PHASEOLUS VULGARIS L.) AS A MODEL TO INVESTIGATE CHANGES IN THE SEED MICROBIOME THAT OCCUR AS A RESULT OF TWO STRESSORS: DROUGHT AND NUTRIENT EXCESS. THESE STRESSORS ARE KEY CHALLENGES FOR SUSTAINABLE AGRICULTURE IN THE FACE OF A CHANGING ENVIRONMENT. WE WILL CONDUCT CONTROLLED EXPERIMENTS TO: 1) QUANTIFY HOW THE SEED MICROBIOME CHANGES AFTER MATERNAL PLANT EXPOSURE TO STRESS; 2A) INVESTIGATE THE GENETIC MECHANISMS OF SEED MICROBIOME ASSEMBLY VIA ROOT EXUDATEDIFFERENCES IN STRESS AND ACROSS GENOTYPES; 2B) INVESTIGATE THE EPIGENETIC MECHANISMS IMPACTING SEED MICROBIOME OUTCOMES DURING STRESS; AND 3) DETERMINE THE IMPLICATIONS OF SEED MICROBIOME MODIFICATIONS FOR THE STRESS TOLERANCE OF THE NEXT PLANT GENERATION. THIS WORK WILL INCLUDE HIGH-THROUGHPUT SEQUENCING OF THE MICROBIOME, CULTIVATION OF SEED BACTERIA, PLANT AND SEED PHENOTYPING, PLANT EPIGENETICS, AND RHIZOSPHERE METABOLOMICS. WE EXPECT THAT THIS WORK WILL PROVIDE INSIGHTS INTO COMPLEX PHYTOBIOME DYNAMICS UNDERLYING PLANT RESPONSES TO ABIOTIC STRESSES OF CONSEQUENCE FOR ENVIRONMENTAL CHANGE.