INNOVATIONS IN AGRICULTURE ARE NEEDED TO MEET GROWING DEMANDS FOR NEW SOURCES OF FOOD AS GLOBAL POPULATION CONTINUES TO RISE. ONE WAY TO INCREASE CROP YIELDS IS TO MAXIMIZE THE AMOUNT OF ENERGY AVAILABLE FOR GROWTH AND FOOD PRODUCTION BY DECREASING THE AMOUNT OF ENERGY CROPS USE TO REPAIR PROTEINS THAT HAVE BEEN DAMAGED BY EXCESS LIGHT. IN ORDER TO ACCOMPLISH THIS, WE NEED TO BETTER UNDERSTAND HOW DIFFERENT ORGANISMS RESIST DAMAGE TO THE PROTEINS THAT CARRY OUT PHOTOSYNTHESIS. THE AFRI FARM BILL PRIORITY AREA "PLANT HEALTH AND PRODUCTION AND PLANT PRODUCTS" AIMS TO PROVIDE A BETTER UNDERSTANDING OF HOW PLANTS GROW, HOW TO IMPROVE THEIR PRODUCTIVITY, AND HOW TO USE PLANTS IN NEW WAYS. THIS PROPOSAL EXEMPLIFIES THIS PRIORITY AREA BY TRYING TO UNDERSTAND HOW THE STRUCTURE OF PSII FROM AN ORGANISM ADAPTED TO A HIGH LIGHT ENVIRONMENT ENHANCES ITS FUNCTION IN EXCESSIVE LIGHT CONDITIONS. THE OBJECTIVES OF THIS PROJECT ARE TO: 1) ISOLATE AND PURIFY PSII FROM C. APONINUM 2) OBTAIN THE STRUCTURE OF PSII BY CRYO-EM, AND 3) TEST THE FUNCTION OF STRUCTURAL FEATURES BY MAKING MUTATIONS INTO OTHER CYANOBACTERIA BASED ON OBSERVATIONS IN THE PSII STRUCTURE WE OBTAIN. ACCOMPLISHING THESE OBJECTIVES WOULD NOT ONLY FULFILL THE REQUIREMENTS SET FORTH BY ASU AND MY GRADUATE ADVISORS TO EARN A PH.D, BUT ALSO COULD HAVE A PROFOUND IMPACT FOR AGRICULTURAL RESEARCH.