ENVIRONMENTAL STRESSES SUCH AS DROUGHT AND HEAT OR COMBINATION ADVERSELY AFFECT PLANT GROWTH AND PRODUCTIVITY, WHICH ULTIMATELY LEADS TO GREAT ECONOMIC LOSS. HEAT STRESS, OFTEN OCCURRED AS EXTREME TEMPERATURE FLUCTUATIONS DURING SUMMERS, ESPECIALLY AT PLANT FLOWER INITIATION STAGE, CAN CAUSE SIGNIFICANT DAMAGES AND AFFECT CROP DEVELOPMENT AND SEED PRODUCTION. HEAT STRESS ALREADY HAS A SUBSTANTIAL ADVERSE IMPACT WORLDWIDE ON AGRICULTURE PRODUCTION. UNDER THE CURRENT GLOBAL-CLIMATE TREND, THE DURATION AND FREQUENCY OF EXTREME HEAT EVENTS BECOMES MORE PREVALENT AND CROP YIELD REDUCTION IS EXPECTED TO BE INCREASED IN FUTURE. IN ORDER TO MEET THE FUTURE DEMAND OF FOOD, FEED AND FIBERS FOR THE GROWING POPULATION, IT IS STRATEGICALLY IMPORTANT TO DEVELOP CROP VARIETIES WITH IMPROVED HEAT TOLERANCE. EXPLORING NEW RESOURCES FOR HEAT TOLERANCE AND IDENTIFYING NOVEL GENES OR REGULATORY ELEMENTS CONTROLLING HEAT TOLERANCE ARE CRITICAL TO IMPROVE CROP HEAT STRESS TOLERANCE. PREVIOUSLY, WE STUDIED HEAT TOLERANCE IN PURSLANE, A XEROPHYTE SPECIES ADAPTED TO HOSTILE ENVIRONMENTS, AND IDENTIFIED POBAG6 AS A POTENTIAL CANDIDATE GENE FOR HEAT TOLERANCE. OVEREXPRESSION OF POBAG6 IN ARABIDOPSIS SIGNIFICANTLY ENHANCED HEAT TOLERANCE AT BOTH VEGETATIVE AND REPRODUCTIVE STAGES. BUILDING ON THIS PRELIMINARY RESEARCH, WE HYPOTHESIS THAT POBAG6 MAY BE A POTENTIAL CANDIDATE GENE THAT CAN BE USED FOR IMPROVEMENT OF CROP SEED PRODUCTION UNDER HEAT STRESS CONDITIONS. IN CURRENT PROJECT, WE INTEND TO TEST THIS HYPOTHESIS BY TRANSFORMING POBAG6 INTO CROP SPECIES, CORN AND SOYBEAN. IN ADDITION, WE WILL ALSO SYSTEMATICALLY INVESTIGATE PHYSIOLOGICAL AND MOLECULAR MECHANISMS THAT CONTROL POBAG6-MEDIATED HEAT TOLERANCE, AND IDENTIFY THE POTENTIAL PHYSICAL PARTNERS INTERACTED WITH POBAG6. THIS PROJECT ADDRESSES THE FUNDAMENTAL ISSUES OF CROP HEAT TOLERANCE AND WOULD GENERATE NEW KNOWLEDGES ON PLANT HEAT TOLERANCE IN GENERAL.