THIS RESEARCH PROJECT FOCUSES ON UNDERSTANDING HOW CARBON TRANSPORT TO ROOTS AFFECTS ROOT GROWTH ANDOVERALL DROUGHT TOLERANCE.PREVIOUS RESEARCH HAS SHOWN THAT THE MAIZE NODAL ROOT SYSTEM, AROOT TYPE UNIQUE TO GRASSES (INCLUDING CEREAL CROPS) THAT SUPPLIES THE BULK OF WATER TO THEPLANT, ARE UNIQUE AMONG PLANT TISSUES IN THEIR CAPACITY FOR CONTINUED GROWTH IN DRY SOIL. THECENTRAL HYPOTHESIS IN THIS PROJECT IS THAT CONTINUED NODAL ROOT GROWTH IS MAINTAINED BYINCREASED CARBON TRANSPORT TO THE NODAL ROOTS DURING WATER DEFICIT. THIS PROJECT AIMS TODEVELOP A BETTER UNDERSTANDING OF THE PHYSIOLOGY OF CARBON TRANSPORT DURING DROUGHT STRESS,AND IDENTIFY GENES INVOLVED IN ROOT GROWTH AND CARBON TRANSPORT DURING DROUGHT. PROGRESS INTHESE AREAS WILL CONTRIBUTE GREATLY TO PLANT HEALTH AND PRODUCTION AS WELL AS CONTRIBUTE TO THEPD'S EDUCATIONAL AND PROFESSIONAL DEVELOPMENT.THE TWO MAIN OBJECTIVES OF THE PROPOSED RESEARCH ARE: 1) CHARACTERIZE CARBON TRANSPORT TONODAL ROOTS DURING PRECISELY-CONTROLLED DROUGHT CONDITIONS; 2) IDENTIFY GENES CONTRIBUTING TOROOT GROWTH AND CARBON TRANSPORT TO ROOTS DURING DROUGHT. FOR THE FIRST OBJECTIVE, I WILL UTILIZEA SPECIALIZED GROWTH APPARATUS THAT IMPOSES PRECISE DROUGHT TREATMENTS, AND I WILL DEVELOP ANEXPERIMENTAL SYSTEM TO MEASURE CARBON TRANSPORT WITHIN THE PLANT. FOR THE SECOND, I WILLLEVERAGE EXISTING DATASETS TO IDENTIFY POTENTIAL GENES REGULATING CARBON TRANSPORT AND ROOTGROWTH, AND THE CARBON TRANSPORT-DEFECTIVE MUTANT ZMSUT1, TO EXPLORE GENETIC CONTROL OFCARBON TRANSPORT TO ROOTS AND DROUGHT TOLERANCE. THIS PROJECT USES MAIZE BUT FINDINGS ARELIKELY TO BE TRANSLATABLE TO OTHER CROPS.