CROPS FACE NUMEROUS STRESSES THAT THREATEN THE PRODUCTIVITY OF OUR FOOD SUPPLY. AMONG THESE CHALLENGES, DROUGHT HAS DEVASTATING IMPACTS ON CROP YIELD. TO FEED OUR GROWING POPULATION, WE NEED INNOVATIVE, SUSTAINABLE SOLUTIONS THAT IMPROVE PLANT RESILIENCE. ONE PROMISING APPROACH IS USING BENEFICIAL BACTERIA THAT PROTECT PLANTS FROM STRESS AND PROMOTE PLANT GROWTH AND YIELD UNDER CHALLENGING CONDITIONS. DESPITE THE POTENTIAL OF THESE BENEFICIAL BACTERIA, THEIR APPLICATION IN AGRICULTURE HAS BEEN MIXED DUE TO THE UNPREDICTABLE INTERACTIONS BETWEEN PLANTS AND BACTERIA. TO ENGINEER CROPS THAT ARE RESILIENT TO STRESS AND INCREASE AGRICULTURAL YIELD, THIS PROJECT WILL CHARACTERIZE THE INTERACTION BETWEEN PLANTS AND BACTERIA AT THE CELLULAR AND MOLECULAR LEVEL. WITH A BETTER UNDERSTANDING OF WHERE, WHEN, AND HOW PLANT-BACTERIA RELATIONSHIPS FORM AND ARE MAINTAINED UNDER DROUGHT, WE CAN STRENGTHEN THIS PARTNERSHIP AND PROMOTE CROP YIELD UNDER DROUGHT AND OTHER STRESSES BROUGHT UPON BY DRASTIC CHANGES IN CLIMATE.THIS PROJECT WILL USE CUTTING-EDGE TECHNOLOGIES TO ANSWER THESE QUESTIONS ABOUT PLANT-BACTERIA INTERACTIONS. FIRST, A VERTICAL MICROSCOPE WILL BE USED TO TRACK WHEN AND WHERE BACTERIA ASSOCIATE WITH THE ROOT UNDER WELL-WATERED AND DROUGHT CONDITIONS. TWO BACTERIA - BACILLUS SUBTILIS AND PSEUDOMONAS PUTIDA -AND FOUR PLANT SPECIES - THE MODEL PLANT ARABIDOPSIS THALIANA, AND THREE CLOSELY-RELATED CROPS:BROCCOLI (BRASSICA OLERACEA VAR ITALICA), CABBAGE (BRASSICA OLERACEA VAR CAPITATA), AND RAPESEED (BRASSICA NAPUS) - WILL BE INVESTIGATED. SEQUENCING AT THE SINGLE-CELL LEVEL WILL BE USED TO IDENTIFY IMPORTANT GENES EXPRESSED IN SPECIFIC ROOT CELLS DURING THESE PLANT-BACTERIA INTERACTIONS UNDER WELL-WATERED AND DROUGHT CONDITIONS. ULTIMATELY, THESE RESULTS WILL INFORM THE ENGINEERING OF PLANTS TO FORM PARTNERSHIPS WITH BENEFICIAL BACTERIA AND ENABLE IMPROVED CROP YIELD AND STRESS RESILIENCE IN AGRICULTURE.