Starch Biosynthesis and the Key Enzymes of Root and Tuber Plants

薯类作物富含淀粉，是我国重要的粮食和食品加工原料，也是变性淀粉和生物质能源的优势原材料。淀粉包含直链淀粉和支链淀粉两种组分，生物合成是其唯一的来源。各类作物中淀粉生物合成由多种功能保守的关键酶类相互协调、共同作用来完成。根据其功能，这些酶分为ADP葡萄糖焦磷酸化酶、淀粉合成酶、淀粉分支酶、淀粉去分支酶等。本文综述了近年来这些关键酶在生物学功能及作用机制上的新进展，分析了淀粉合成过程中可能包含的新酶种类如淀粉磷酸化酶、D-酶等的功能，并总结了这些酶类在薯类作物直链淀粉和支链淀粉合成中的功能特点。这为开展薯类作物中淀粉合成酶的鉴别和功能研究，以及建立薯类淀粉结构与性质的关联性提供了重要的参考。 The tuber and root crops are rich in starch in their storage organs and provide important raw mate- rials not only for food and processed food, but also for modified starches and bioenergy. Starch is composed of two types of molecules, amylose and amylopectin. It can only be produced through biosynthetic pathway, a process that involves multiple enzymes of conserved functions in many crops, such as ADP-glucose phos- phorylase, starch synthases, starch branching enzymes and starch debranching enzymes. Here we review re- cent progresses in biological functions and mechanisms of these key enzymes in starch biosynthesis, include- ing new identified enzymes such as starch phosphorylase and D-enzyme. Their features in amylose and amy- lopectin biosynthesis of tuber and root crops were also explored. It not only provides important information for identification and functional analysis of key enzymes in starch biosynthesis but also bridges the gap be- tween starch structure and property of tuber and root crops.