A LONG-STANDING CHALLENGE IN POSTHARVEST BIOLOGY HAS BEEN TO UNDERSTAND THE KEY FACTORS THAT AFFECT WATER LOSS, AND TO DEVELOP STRATEGIES TO REDUCE DESICCATION AND CONSEQUENT CROP SPOILAGE: A PROBLEM OF ENORMOUS ECONOMIC IMPORTANCE. WHILE IT IS KNOWN THAT THE WAXY CUTICLE, OR 'SKIN', OF FRUIT PROVIDES THE PRIMARY BARRIER TO WATER LOSS, THE CONTRIBUTIONS OF INDIVIDUAL CUTICLE CONSTITUENTS, AND THE MECHANISMS BY WHICH THEY ARE INCORPORATED INTO THE CUTICLE ARCHITECTURE, ARE NOT WELL UNDERSTOOD. IN THIS PROJECT, USING TOMATO FRUIT AS A MODEL, A BROAD RANGE OF ANALYTICAL APPROACHES WILL BE USED TO TEST THE HYPOTHESES THAT: 1) THE CUTIN SYNTHASE (CUS) AND CUTICLE DESTRUCTING FACTOR (CDEF) ENZYME FAMILIES OPERATED TOGETHER TO ASSEMBLE AND RESTRUCTURE, RESPECTIVELY, ONE OF THE MAJOR CUTICLE COMPONENTS, CUTIN; AND 2) THIS DYNAMIC PROCESS IS ESSENTIAL TO MAINTAIN CUTICLE INTEGRITY DURING FRUIT DEVELOPMENT; AND 3) THIS PROCESS PROVIDES A CRITICAL 'SELF-SEALING' REPAIR SYSTEM TO LIMIT WATER LOSS.