Molecular Biology of Plant Cuticular Waxes

9808559可协调生存要求有机体在自身和环境之间建立一道保护性屏障。由于有机体必须能够感知和响应环境信号，这种屏障还必须允许分子和信息的交换。在植物中，角质层起着这个屏障的作用。除了起到水屏障的作用外，人们还认为角质层提供了抗霜冻和紫外线的能力，并在植物与病原菌的相互作用中发挥了作用。此外，角质层的性质极大地影响农药、生长调节剂和喷洒在植物上的叶营养等农用化学品的沉积和行为。角质蜡是角质层的重要组成部分。它们是由VLCFA延长酶系统在植物表皮细胞中制造的超长链脂肪酸的酰基衍生物的复杂混合物。负责产生其中一种酶功能的玉米基因(GL8)已经被克隆，而产生功能性VLCFA伸长酶系统所需的其他基因也将被克隆。这种综合的研究方法将加深我们对酰基链伸长的机理的理解。由于相似类型的延伸反应在许多种类的分子(包括多酮类、黄酮类和二苯乙烯类)的生物合成中是重要的，这些分子具有抗生素、植物病原体毒素、色素和保护化合物的功能，因此拟议的研究将影响我们对许多基本生物过程的理解和操纵的能力。

9808559 Schnable Survival requires that organisms produce a protective barrier between themselves and their environment. Because organisms must be able to sense and respond to environmental signals, this barrier must also allow for an exchange of molecules and information. In plants, the cuticle serves as this barrier. In addition to functioning as a water barrier, it has been suggested that the cuticle provides frost and UV resistance and plays a role in plant-pathogen interactions. Furthermore, the nature of the cuticle greatly affects the deposition and behavior of agricultural chemicals such as pesticides, growth regulators and foliar nutrients sprayed on plants. Cuticular waxes are an important component of the cuticle. They are complex mixtures of acyl derivatives of very long-chain fatty acids made in plant epidermal cells by VLCFA elongase enzyme systems. A maize gene (gl8) responsible for the production of one of these enzymatic functions has been cloned, and the other genes required for the production of functional VLCFA elongase enzyme systems will be cloned. This integrated research approach will enhance our understanding of the mechanism by which the elongation of acyl chains occurs. Because similar types elongation reactions are important in the biosynthesis of many classes of molecules (including polyketides, flavonoids, and stilbenoids) which function as antibiotics, plant-pathogen toxins, pigments and protective compounds, the proposed studies will impact our understanding and ability to manipulate many fundamental biological processes