【摘要】 为弄清香蕉果实可溶性淀粉合成酶基因(MaSSⅢ-1)的分子特征及时空表达模式,以‘巴西蕉’果肉为试材,采用PCR法进行MaSSⅢ-1基因克隆,通过Quantitative real-time PCR (qPCR)和Western blot技术对MaSSⅢ-1基因及其蛋白表达模式进行分析。结果显示:MaSSⅢ-1基因cDNA全长为2397 bp,编码798个氨基酸,包括4个典型的结构域,GenBank登录号为KU757067。MaSSⅢ-1基因在香蕉根、球茎、花和苞片中表达量较低,在叶、果皮和果肉中表达量较高;随着香蕉果实发育,MaSSⅢ-1基因表达量逐渐上升,在抽蕾后50～60天达到最大;随着果实采后成熟,MaSSⅢ-1表达量在采后5天达到最大,随后逐渐下降。在香蕉果实不同发育及采后成熟阶段,MaSSⅢ-1蛋白呈现出与mRNA水平相一致的表达趋势。证明MaSSⅢ-1基因的表达不仅涉及到香蕉果实支链淀粉合成代谢,可能还涉及采后早期果实成熟或者支链淀粉降解。更多还原

【Abstract】 To clarify the molecular characteristics and temporal and spatial expression patterns of soluble starch synthase Ⅲ-1 gene(MaSSⅢ-1), using the‘Brazilian’banana pulps as the test material, the MaSSⅢ-1 genewas cloned by PCR method. Quantitative real-time PCR(qPCR) and Western blot technology were used toanalyze MaSSⅢ-1 gene and its protein expression pattern. The results showed that the cDNA full-length of MaSSⅢ-1 gene(accession No. KU757067) was 2397 bp encoding 798 amino acids with four typical domains.The expression level of MaSSⅢ-1 was low in roots, bulbs, flowers, and bracts, but it exhibited high expressionin leaves, peels, and pulps. Moreover, MaSSⅢ-1 expression increased gradually with banana fruitdevelopment, and then reached the highest expression in 50-60 d after emergence from the pseudostem. The expression level of MaSSⅢ-1 reached the maximum value in 5 d after harvest and then decreased graduallyduring postharvest ripening in banana fruit. The expression pattern of MaSSⅢ-1 protein was consistent withthe expression trend at mRNA level during banana fruit development and ripening. These results suggestedthat the expression of MaSSⅢ-1 gene may involve not only amylopectin biosynthesis but also early fruitripening or amylopectin degradation in banana.更多还原