植物乙酰辅酶A羧化酶的分子生物学与基因工程

植物中的乙酰辅酶A羧化酶(acetylCoAcarboxylase,ACCase)分两种类型:原核类型的ACCase位于质体中,是脂肪酸合成途径中的关键酶;真核类型的ACCase位于胞质溶胶中,催化形成的产物主要用于长链脂肪酸的合成以及类黄酮等次生代谢产物的合成。但禾本科植物的质体和胞质溶胶中的ACCase都属于真核类型,其中质体中的是环己烯酮类和芳氧苯氧丙酸类等除草剂作用的靶蛋白。文中主要综述了植物中ACCase的生理功能、分子生物学特征及其对两类除草剂的敏感性,并对其基因工程作了展望。

Molecular Biology and Gene Engineering of Plant Acetyl-CoA Carboxylase

Most plants have two forms of acetyl-CoA carboxylase (ACCase): the eukaryotic form, composed of a large multifunctional polypeptide in cytosol, and the prokaryotic form, composed of four different polypeptides in plastids. Plant fatty acids are mainly synthesized in plastids and the prokaryotic form of ACCase regulates the rate of fatty acid synthesis in most plants. In the cytosol of plant cell, the eukaryotic form ACCase provides malonyl-CoA for fatty acid elongation, flavonoid formation, polyketide synthesis, and several other metabolic pathways. Gramineae have the eukaryotic form both in cytosol and plastids, ACCase in plastids is the primary target site of two classes of grass herbicides, the cyclohexanediones (CHDs) and aryloxyphenoxypropionic acids (AOPPs). In this review, the physiological function, molecular characterization, as well as the herbicide sensitivity of plant ACCase are described, and the trend in plant ACCase gene engineering is also discussed. ;