CAJ | 학술논문

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。
위천명소맥지련정분합성적매학궤제,이8개소맥품충적자립위재료,채용비변성취병희선알응효전영(Native-PAGE)화 SDS 취병희선알응효전영(SDS-PAGE)감정 SBE 동공매류형、시공표체보급아기조성,분석 SBE 동공매공간분포특점화기관표체특이성。공검측도4충 SBE 동공매,기중 B 화 SBEIIa 분포재배유화협편중,이 A 화Di 전일정위우배유중。재소맥자립관장과정중, Di 화 SBEIIa 수선표체,이후시 B, A 최후표체；지관장말기, B 화SBEIIa 정지표체。SBE 동공매도시단아기매,균유일조86~92 kD 적다태련조성。SBE 동공매적공간분포구유기관특이성,병재자립발육진정중순서표체。Di、B 화 SBEIIa 시점주도지위적 SBE 동공매,가능시결정 SBE 총매활성적주효응매,재자립화협편지련정분합성중기관건작용。
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.