Molecular Structure and Function of Fruit Cuticle Polyesters

高等植物的角质层主要是作为叶子和果实的保护屏障，控制微生物的攻击以及水和化学物质的扩散。它的主要化学成分是提供防水的蜡和两种不溶性结构聚合物，角质和木质素中的任何一种。该项目旨在了解单体单元如何连接在一起并与细胞壁基质相连，应力如何改变膜的超分子结构和表面微观结构，以及在伤口愈合过程中如何合成木质素聚合物。我们将采用几种生物物理学的方法来解决这些问题。(1)用化学方法制备石灰角质和马铃薯木质素的低聚片段，并利用高效液相色谱、质谱和核磁共振（NMR）进行鉴定。(2)利用固态13C和2H核磁共振（NMR）评估完整番茄角质层在风、温度和水化胁迫下的柔韧性和相分离。(3)利用原子力显微镜（AFM）研究番茄角质层表面形貌和微观力学性能对脱蜡、膨胀和水性洗涤剂应用的响应。(4)通过可溶性酚代谢和不溶性细胞壁结合物质的光谱分析，监测马铃薯创面愈合组织中亚木素的生物合成，包括饲喂富含13c的前体。该项目的总体目标包括了解保护性角质层和木聚糖生物聚合物的单体单元如何连接在一起并支持细胞壁基质，环境压力（如风蚀、高湿和温度冲击）如何改变角质层膜的结构，以及伤口愈合过程中植物组织如何合成木聚糖聚合物。最终，这项研究应该对农业和经济都有影响，有助于设计基本的作物保护战略。更广泛地说，从这项工作中获得的微观结构和分子见解可能有助于工业或化妆品用途的合成防水材料的开发。最后，该项目将有助于向植物科学家社区介绍固态核磁共振和原子力显微镜等方法。* * *

9728503 Stark The cuticle of higher plants functions primarily as a protective barrier for the leaves and fruit, controlling microbial 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. This project aims to understand how the monomer units are linked together and to cell-wall matrices, how stresses alter the membrane's supramolecular architecture and surface microstructure, and how the suberin polymer is synthesized during wound healing. Several biophysical approaches will be taken to these problems. (1) Oligomeric fragments of lime cutin and potato suberin will be produced chemically and identified using high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance (NMR). (2) The flexibility and phase segregation of intact tomato cuticles will be assessed in response to wind, temperature, and hydration stress using solid-state 13C and 2H NMR. (3) The response of tomato cuticle surface topography and micromechanical properties to dewaxing, swelling, and application of aqueous detergents will be examined using atomic force microscopy (AFM). (4) The biosynthesis of suberin in wound-healing potato tissues, including feeding with 13C-enriched precursors, will be monitored through spectroscopic analysis of soluble phenolic metabolities and insoluble cell-wall bound materials. The overall objectives of this project include understanding how the monomer units of the protective cutin and suberin biopolymers are linked together and to supporting cell-wall matrices, how environmental stresses such as wind abrasion, high humidity, and temperature shock alter the architecture of the cuticular membrane, and how the suberin polymer is synthesized by the plant tissue during wound healing. Ultimately, this research should have both agricultural and economic impact, aiding in the design of essential crop protection strategies. More b roadly, the microstructural and molecular insights developed from this work may assist the development of synthetic waterproofing materials for industrial or cosmetic use. Finally, this project will serve to introduce methods such as solid-state NMR and AFM to the community of plant scientists. ***