9406354 Stark The cuticle of higher plants functions primarily as a protective barrier for the leaves and fruit, controlling bacterial and fungal attack as well as the diffusion of water and chemicals. Its major chemical constituents are waxes that provide waterproofing and either of two insoluble structural polymers, cutin and suberin. Our objectives are to understand how the monomer units of cutin and suberin are linked together, how the polymers are embedded within wax or cell-wall matrices, and how their supramolecular architecture is related to cuticular function. Several new spectroscopic and biochemical initiatives are proposed: (1) the effects of temperature stress on tomato cuticle function and flexibility will be monitored by measuring its permeability and conducting solid-state 13C nuclear magnetic resonance (NMR) experiments; (2) the effects of swelling on the cuticular netting will be assessed with 13C and 2H NMR measurements on the cutin and water, respectively; (3) oligomeric fragments of fruit cutin and potato suberin will be produced enzymatically and identified using high-performance liquid chromatography, mass spectrometry, and solution-state NMR; (4) the development and molecular structure of suberin within wound-healing potato tissue will be examined using both uniform and selective 13C and 2H labelling, in conjunction with advanced 13C and double-resonance NMR experiments. %%% Our overall goal is to understand the chemical structures that make the outer cuticular skin of fruits resilient and resistant to pathogenic attack, especially under conditions of environmental stress. By studying the biosynthesis and structural development of suberin that forms on the surface of wounded plant tissue, we also hope to design methods to enhance this protective process. Since polymeric mixtures are involved in both of these cuticular membranes, our research may have future applications in the design of synthetic coating (waterproofing) and composites (adhesives). ***
