Molecular Structure and Biomechanics of Plant Cuticular Membranes

高等植物的角质层是一种多功能的调节器，可以调节来自外部环境的水和化学物质的流动，并对细菌和真菌的攻击进行强大的防御。 蜡沉积在角质聚酯上，而木栓质和聚（酚）则存在于次生生长组织中或作为应激反应形成。 水果保鲜膜是智能表面-能够在成熟过程中进行空间选择性自清洁和调节其最佳机械性能。 建立分子和介观结构的保护功能，这些显着的生物材料，而不破坏其独特的性能，固态核磁共振，生物力学分析和原子力显微镜的完整的生物聚合物将协调检查共价结构和动力学，应力-应变曲线，粘弹性和表面拓扑结构。 三个番茄果实角质层系统将被用来测试假设涉及角质分子结构及其组织的影响，蜡和细胞壁的机械完整性的水果caudience：一个商业品种，其中表皮蜡已被删除模型环境压力和两种类型的遗传特征角质缺陷的水果突变体。 该项目的主题相关目标包括优化完整果实角质层的结构和功能表征方法，测试在蜡磨损胁迫下维持果实角质层完整性的机制模型，评估角质/蜡比率，数量和分支结构如何阻止角质层缺陷突变果实中形成均匀屏障，和测试提出的建筑原因和早熟脱水突变体中微裂缝的后果。一个多尺度的方法来水果角质层的完整性具有广泛的潜力，在植物分子生物学家和遗传学家，物理化学家和生物工程师之间的智力协同作用。 本研究结果将指导设计策略，以提高农业重要粮食作物的抗寒性和产量。 对这些非凡的天然植物界面的机械性能的研究结果也应该激发自清洁涂料和纤维增强防水材料的仿生设计。 为这项研究开发的新的核磁共振方法将通过NSF赞助的研究协调网络传播。 最后，该项目的教育影响将包括大分子组装生物物理学的跨学科培训，在招收超过60%的西班牙裔和黑人学生的校园和授予近10%美国的大学进行。的专业是化学和化学工程。 该项目将成为两个新的外展计划的基础，这两个计划以纽约市立大学为基地，针对附近的上曼哈顿和布朗克斯高中，这些高中有大量的少数民族人口：（1）一个学期的实验室为基础的植物生物聚合物课程，该课程是为纽约市立大学与纽约市教育局合作的20名学生设计的;以及（2）与CCNY的Pathways生物信息学和生物分子中心协调的40名学生网关实验室研究培训研讨会。

The cuticle of higher plants serves as a versatile regulator of the flow of water and chemicals from the outside environment and a robust defense against bacterial and fungal attack. Waxes are deposited on a cutin polyester whereas suberin and poly(phenolics) are found in secondary growth tissues or formed as a stress response. Fruit cuticles are smart surfaces - capable of spatially selective self cleaning and regulation of their superlative mechanical performance during ripening. To establish the molecular and mesoscopic architectures underlying the protective functions of these remarkable biomaterials without destroying their unique properties, solid-state nuclear magnetic resonance, biomechanical analysis, and atomic force microscopy of the intact biopolymers will be coordinated to examine covalent structure and dynamics, stress-strain profiles, viscoelasticity, and surface topology. Three tomato fruit cuticle systems will be used to test hypotheses involving the influence of cutin molecular structure and its organization with waxes and cell walls on the mechanical integrity of fruit cuticles: a commercial cultivar from which epicuticular waxes have been removed to model environmental stress and two types of genetically characterized cuticle-deficient fruit mutants. The thematically related goals of this project include optimization of methods for structural and functional characterization of intact fruit cuticles, testing of mechanistic models for maintenance of fruit cuticle integrity under wax abrasion stress, evaluation of how cutin/wax ratios, amounts, and branched structures preclude formation of a homogeneous barrier in cuticle deficient mutant fruits, and testing of proposed architectural causes and consequences of microfissuring in precocious dehydration mutants.A multiscale approach to fruit cuticle integrity has broad potential for intellectual synergy among plant molecular biologists and geneticists, physical chemists, and bioengineers. The results of this research will guide the design strategies to enhance the hardiness and yield of agriculturally important food crops. Findings on the mechanical performance of these remarkable natural plant interfaces should also inspire the biomimetic design of self-cleaning paints and fiber-reinforced waterproofing. New NMR methodology developed for this research will be disseminated through an NSF-sponsored Research Coordination Network. Finally, the educational impact of this project will include interdisciplinary training in the biophysics of macromolecular assemblies, conducted on a campus that enrolls more than 60% Hispanic and Black students and at a university that awards almost 10% of U.S. African-American Ph.D.'s in Chemistry and Chemical Engineering. The project will form the basis for two new outreach initiatives based at CCNY and targeting nearby Upper Manhattan and Bronx high schools with substantial minority populations: (1) a semester-long lab-based Plant Biopolymers course designed for 20-student classes in CUNY's College Now partnership with the NYC Department of Education; and (2) a 40-student Gateway Lab research training workshop coordinated with CCNY's Pathways Bioinformatics and Biomolecular Center.