** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** BARLEY, A VITAL CROP WORLDWIDE, SUFFERS FROM A BACTERIAL DISEASE CAUSED BY XT. UNFORTUNATELY, WE DON'T FULLY UNDERSTAND HOW BARLEY PLANTS FIGHT BACK AGAINST THIS INFECTION AT THE CELLULAR LEVEL. PLANTS HAVE COMPLEX DEFENSES, AND OUR EARLY FINDINGS SUGGEST XT DOESN'T INFECT ALL BARLEY LEAF CELLS EQUALLY. ADDITIONALLY, THE WAY THE BACTERIA INJECTS TOXINS (THROUGH A SYSTEM CALLED T3SS) MAY VARY DEPENDING ON THE TARGETED CELL.CURRENT RESEARCH ON PLANT-BACTERIA BATTLES OFTEN LOOKS AT THE ENTIRE PLANT AT ONCE, MISSING THE FINER DETAILS HAPPENING WITHIN INDIVIDUAL CELLS. THIS PROJECT AIMS TO ZOOM IN ON THESE DETAILS, FOLLOWING XT INFECTION OVER TIME AND SPACE WITHIN BARLEY LEAVES.HERE'S WHAT WE WANT TO ACHIEVE:OBJECTIVE 1:UNDERSTAND HOW THE FIGHT BETWEEN THE BACTERIA AND THE PLANT'S DEFENSES UNFOLDS IN DIFFERENT PARTS OF THE LEAF AND OVER TIME.OBJECTIVE 2:COMPARE THE GENE ACTIVITY (THE PLANT'S BATTLE PLAN) IN BOTH THE ENTIRE LEAF AND INDIVIDUAL CELLS AFTER INFECTION.OBJECTIVE 3:TRACK HOW THE PLANT'S DEFENSES TURN ON OR OFF IN DIFFERENT AREAS OF THE LEAF AS THE INFECTION PROGRESSES.BY UNDERSTANDING THE WHO, WHAT, WHERE, AND WHEN OF THE BATTLE WITHIN BARLEY LEAVES, THIS PROJECT WILL PROVIDE VALUABLE INSIGHTS INTO HOW PLANTS FIGHT DISEASE. THIS KNOWLEDGE WILL BE KEY FOR DEVELOPING NEW STRATEGIES TO PROTECT BARLEY CROPS FROM XT AND OTHER BACTERIAL FOES.