香蕉MaCSase基因的克隆和表达分析

Molecular Cloning and Expression Analysis of MaCSase Gene in Banana

旨在克隆香蕉(Musa acuminataL.AAA groupcv.Brazilian)半胱氨酸合成酶(cysteine synthase,CSase)基因,并进行序列特征、器官表达特异性和逆境胁迫下表达特性分析。通过对香蕉根的cDNA文库的测序和分析,获得了一段香蕉半胱氨酸合成酶基因的片段,运用RACE扩增技术获得基因全长,命名为MaCSase,并进行序列分析,最后利用荧光定量PCR技术分析该基因在香蕉不同器官中的表达特异性及在外源胁迫下的表达特性。序列分析显示,该基因全长1367bp,存在1个完整的开放阅读框1065bp,编码355个氨基酸。通过和已知植物的半胱氨酸合成酶基因相比,同源性达到79%以上。其中与水稻、苜蓿、葱、玉米的CSase编码的氨基酸序列的同源性分别为86%、85%、84%、84%,器官特异性分析表明,MaCSase在香蕉的根、球茎、叶片、花和果实中均有所表达,其中在球茎中表达量最高。通过对其在高盐胁迫下的表达分析显示,该基因在香蕉根中的表达随着处理时间的增加呈现上升趋势,在胁迫6h时被大量诱导。

In this study,the obtainment and sequence analysis of the cysteine synthase gene from banana（Musa acuminata L.AAA group cv.Brazilian） was conducted,and then its expression profiles in different organs and under the stress treatment were also carried out.Through RACE approaches and bioinformatics analysis,the full-length cDNA of the cysteine synthase gene,named as MaCSase,was obtained from root of banana cDNA library,and its sequence characters were also analyzed.The expression levels of MaCSase in different organs and the expression profiles of MaCSase in banana root under the exogenetic stresse were analyzed by Real-time qPCR.Sequence analysis showed that the full-length cDNA sequence of MaCSase was 1367 bp.MaCSase had a 1065 bp open reading frame in length encoding 355 amino acids.Compared with other plants,the homology of MaCSase was more than 79%.The amino acid identity compared with Oryza sativa,Medicago sativa,Allium sativum and Zea mays was 86%,85%,84%,84% respectively.Organs specific analysis showed that MaCSase was constitutively expressed in roots,stems,leaves,flowers and fruits.The expression level was higher in stems.Analysis showed that the expression of MaCSase in the banana root was up-regulated with the increase of the processing time under the salt stress.It was strongly induced at the 6 h stress.