小麦籽粒淀粉分支酶同工酶结构组成及时空表达  

Constitution and Spatiotemporal Expression of Starch Branching Enzyme in Developing Wheat Grain

作　　者：刘正帅[1] 刘贵芬[1] 杨明煜[2] 贾晓[1] 李运祥[1] 赵法茂[1] 

机构地区：[1]泰山学院生物与酿酒工程学院,山东泰安271021 [2]泰安市第一中学,山东泰安271000

出　　处：《作物学报》2014年第12期2176-2182,共7页Acta Agronomica Sinica

基　　金：山东省自然科学基金项目(ZR2010CM034);2013年全国大学生创新创业训练计划资助

摘　　要：为阐明小麦支链淀粉合成的酶学机制,以8个小麦品种的籽粒为材料,采用非变性聚丙烯酰胺凝胶电泳（Native-PAGE）和SDS聚丙烯酰胺凝胶电泳（SDS-PAGE）鉴定SBE同工酶类型、时空表达谱及亚基组成,分析SBE同工酶空间分布特点和器官表达特异性。共检测到4种SBE同工酶,其中B和SBEⅡa分布在胚乳和叶片中,而A和Di专一定位于胚乳中。在小麦籽粒灌浆过程中,Di和SBEⅡa首先表达,而后是B,A最后表达;至灌浆末期,B和SBEⅡa停止表达。SBE同工酶都是单亚基酶,均由一条86-92 kD的多肽链组成。SBE同工酶的空间分布具有器官特异性,并在籽粒发育进程中顺序表达。Di、B和SBEⅡa是占主导地位的SBE同工酶,可能是决定SBE总酶活性的主效应酶,在籽粒和叶片支链淀粉合成中起关键作用。This study aimed at disclosing the enzymatic mechanism in amylopectin synthesis in wheat （Triticum aestivum L.）. The isozyme forms, organ localization, spatiotemporal expression profile and subunits constitution of starch branching enzyme （SBE） were identified in eight wheat cultivars from different provenances using native polyacrylamide gel electrophoresis （Native-PAGE） and SDS-PAGE. Four SBE isozymes were detected in wheat endosperm, in which isozymes B and SBEIIa were localized in en-dosperm and leaf, whereas isozymes A and Di were exclusively present in endosperm. In the process of grain filling, Di and SBEIIa expressed first, followed by isozyme B, and isozyme A expressed finally. However, B and SBEIIa terminated to express at late filling stage. All SBE isozymes were composed of one subunit of 86–92 kD, and their spatial localization exhibited organ specificity. According to the expression level, Di, B, and SBEIIa are considered as dominant isozymes for grain endosperm de-velopment. They probably determinate the total SBE activity and serve as key factors in amylpectin biosynthesis in wheat grain and leaf.

关 键 词：小麦 淀粉分支酶 支链淀粉 时空表达 器官分布 

分 类 号：S512.1[农业科学—作物学]