ADDRESSING THE LOOMING GLOBAL FOOD SECURITY CRISIS REQUIRES THE DEVELOPMENT OF HIGHER-YIELDING CROPS IN THE FACE OF POPULATION GROWTH AND DECREASING ARABLE LAND RESOURCES. IN THIS REGARD, IT HAS BEEN KNOWN FOR DECADES THAT DEFICIENCY FOR A MICRONUTRIENT COPPER IN ALKALINE, COARSE-TEXTURED OR ORGANIC SOILS COMPROMISES CROP FERTILITY AND REDUCES GRAIN/SEED YIELD. HOWEVER, THE PHYSIOLOGICAL, MOLECULAR AND GENETIC MECHANISMS UNDERLYING THIS TRAIT ARE UNKNOWN. WHEAT IS ONE OF THE MOST IMPORTANT STAPLE FOOD CROPS, WHICH IS ALSO REGARDED AS MOST SENSITIVE TO COPPER DEFICIENCY. HOW COPPER UPTAKE AND INTERNAL TRANSPORT IN WHEAT IS ACHIEVED AND REGULATED, AND HOW COPPER TRANSPORT PROCESSES IMPACT WHEAT FERTILITY ARE UNKNOWN AS WELL. SCIENTISTS HAVE LEARNED MUCH MORE ABOUT COPPER HOMEOSTASIS IN MODEL SPECIES SUCH AS ARABIDOPSIS THALIANA. FOR EXAMPLE, RECENT DISCOVERIES IN THE PI LAB HAVE LINKED THE FUNCTION OF TWO PROTEINS, ATCITF1 (A. THALIANA COPPER-DEFICIENCY INDUCED TRANSCRIPTION FACTOR 1) AND ATSPL7 (A. THALIANA SQUAMOSA PROMOTER BINDING PROTEIN LIKE7) TO COPPER UPTAKE, DELIVERY TO ANTHERS AND FERTILITY IN A MODEL DICOTYLEDONOUS SPECIES, A. THALIANA. WHETHER A SIMILAR PATHWAY REGULATES COPPER UPTAKE AND DELIVERY TO REPRODUCTIVE ORGANS IN WHEAT AND WHETHER IT AFFECTS WHEAT FERTILITY, IS UNKNOWN.THIS PROJECT USES INTERDISCIPLINARY APPROACHES TO PROVIDE FUNDAMENTAL INSIGHTS INTO THE FUNCTION OF THE SPL7 PATHWAY IN COORDINATING COPPER TRANSPORT PROCESSES AND FERTILITY IN WHEAT AND ITS PROXY, BRACHYPODIUM DISTACHYON (BRACHYPODIUM) AND TO ESTABLISH THE PHYSIOLOGICAL, MOLECULAR AND GENETIC MECHANISM(S) UNDERLYING COPPER UPTAKE, DELIVERY TO REPRODUCTIVE ORGANS AND FERTILITY. MORE SPECIFICALLY, THIS RESEARCH WILL: 1) PERFORM DETAILED FUNCTIONAL ANALYSIS OF SPL7 GENES FUNCTION IN WHEAT AND BRACHYPODIUM USING MULTIFACETED FUNCTIONAL GENETIC TOOLS. 2) IDENTIFY NEW COPPER DEFICIENCY-RESPONSIVE PROTEINS THAT ARE INVOLVED IN COPPER DELIVERY TO REPRODUCTIVE ORGANS IN WHEAT AND BRACHYPODIUM AND NEW REGULATORS OF COPPER TRANSPORT PROCESSES IN THESE PLANT SPECIES. 3) PERFORM THE GENOME-WIDE CROSS-SPECIES COMPARISONS OF COPPER DEFICIENCY RESPONSIVE AND SPL7-REGULATED GENES. 4) IDENTIFY NEW CHROMOSOMAL REGIONS IN WHEAT ASSOCIATED WITH THE IMPROVED COPPER MOVEMENT TO REPRODUCTIVE ORGANS AND GRAIN YIELD.THIS NEW KNOWLEDGE WILL AID THE IMPROVEMENT OF CEREALS PRODUCTIVITY AND GRAIN YIELD ON MARGINAL SOILS AND SOILS CURRENTLY IN CULTIVATION. THIS PROJECT IS RELEVANT TO THE "NUTRIENT UPTAKE" PRIORITY OF THE "PHYSIOLOGY OF AGRICULTURAL PLANTS" PROGRAM AREA.