甜高粱可溶性酸性转化酶基因(SAI-1)cDNA全长克隆及表达分析

Full Length cDNA Cloning and Expression Analysis of Soluble Acid Invertase Gene(SAI-1) in Sweet Sorghum(Sorghum bicolor)

可溶性酸性转化酶(SAI)是甜高粱蔗糖代谢关键调控酶。本研究利用RT-PCR的方法,克隆得到了甜高粱SAI-1基因cDNA全长序列(Genbank No.:KF921516),并利用生物信息学方法对其结构以及蛋白功能进行了分析。结果表明:克隆得到的SAI-1 cDNA序列长2 345 bp,包含一个2 025 bp的编码区、210 bp的5'非翻译区和110 bp的3'非翻译区。其编码674个氨基酸蛋白,预测分子量为73.42 kD,等电点为5.76,蛋白序列含有一个完整的糖基水解酶家族32结构域,具有水解蔗糖的作用。甜高粱茎秆中的SAI-1表达水平在拔节和抽穗期较高,而在开花期后的各个时期均处于较低水平,这与甜高粱糖分积累呈负相关。本研究结果为进一步研究SAI-1基因调控甜高粱糖分含量的分子机制奠定了基础。

Soluble acid invertase （SAI） plays a key role in sucrose metabolism of sweet sorghum stem. In this paper, a novel full-length soluble acid invertase gene （SAI-1） cDNA sequence in sweet sorghum was cloned by RT-PCR. The full-length cDNA of SAI-1 gene is 2 345 bp long, which contained 210 bp 5＇UTR and 110 bp 3＇UTR and the coding region encode a protein with 674 amino acids, which contained a complete glycosyl hydrolase family 32 domains with the effect of hydrolysis of sucrose. The SAI-1 gene in sweet sorghum stem demonstrated a higher mRNA level at elongation and heading stage and a lower level after the flowering. This trend was quite the reverse as sugar accumulation in sweet sorghum stem. The results will provide a basis for further research on molecular mechanism of sucrose accumulation in sweet sorghum stem.