** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** PLANTS ARE SESSILE ORGANISMS THAT RELY ON QUICKLY ADAPTING TO THEIR ENVIRONMENT. THEY MAKE UP A LARGE PORTION OF HUMAN NECESSITIES--FOOD, TEXTILES, AND MEDICINE. AS THE POPULATION INCREASES, WE LOSE AREAS TO GROW THESE VITAL RESOURCES DUE TO CLIMATE CHANGE, GLOBAL WATER RESTRAINTS, AND LOSS OF ARABLE LAND. TO MEET AN EVER-INCREASING DEMAND, PLANT ABIOTIC STRESS RESEARCH IS PIVOTAL TO ADDRESSING THESE CONCERNS IN AN UNPREDICTABLE FUTURE. RIBONUCLEIC ACID (RNA) IS A CORNERSTONE MOLECULE INVOLVED IN RELYING GENETIC MATERIAL INTO FUNCTIONAL PROTEINS AMONG MANY OTHER FUNCTIONS. RNA CAN BE MODIFIED IN OVER 170 WAYS WHICH CAN ALTER THE RNA'S INTENDED FUNCTION. ONE SUCH RNA MODIFICATION IS PSEUDOURIDINE, KNOWN TO BE HEAT-RESPONSIVE IN YEAST MESSENGER RNA (MRNA) AND KNOWN TO AFFECT ALTERNATIVE SPLICING IN HUMANS. HOWEVER, PSEUDOURIDINE'S ROLE(S) IN PLANTS HAVE YET TO BE MOLECULARLY DEFINED. THIS RESEARCH WILL IDENTIFY CANDIDATE PSEUDOURIDINE SYNTHASES (PUSS) INVOLVED IN ABIOTIC STRESS RESPONSE BY UTILIZING MUTANTS THAT NO LONGER EXPRESS THEIR RESPECTIVE PUS GENE. IN ADDITION, SELECTED MUTANTS WILL BE USED TO DETECT DEPLETED PSEUDOURIDINE SITES IMPORTANT FOR ABIOTIC STRESS RESPONSE. FINALLY, MUTANTS WILL BE USED TO INVESTIGATE HOW PSEUDOURIDINE DEPLETION AFFECTS MOLECULAR PROCESSES SUCH AS ALTERNATIVE SPLICING AND PROTEIN INTERACTIONS WITH AND WITHOUT STRESS. DEFINING HOW PSEUDOURIDINE FUNCTIONS IN PLANT ABIOTIC STRESS RESPONSE WILL BENEFIT THE PRODUCTION AND STABILITY OF PLANT RESOURCES IN THE FUTURE.