白芨环阿屯醇合酶基因BsCAS的克隆及序列分析

Cloning and Sequence Analysis of Cycloartenol Synthase Gene BsCAS from Bletilla striata

环阿屯醇合酶(cycloartenol synthase, CAS)在植物甾醇和三萜类物质的合成途径中发挥重要调节作用,研究白芨环阿屯醇合酶BsCAS的序列信息,为进一步研究环阿屯醇合酶的功能奠定基础。基于白芨转录组数据,利用RT-PCR技术扩增BsCAS基因的CDS全长,通过生物信息学软件分析BsCAS蛋白的理化性质和结构特征,并进行氨基酸多序列比对分析与系统进化树分析。结果表明扩增获得的Bs CAS基因CDS全长为2 277 bp,编码758个氨基酸。BsCAS蛋白是无跨膜结构无信号肽的亲水性蛋白,BsCAS蛋白具典型的DCTAE结构域和QW结构域,属于氧化鲨烯环化酶超基因家族成员。BsCAS与铁皮石斛和小兰屿蝴蝶兰的CAS蛋白具有很高的同源性,亲缘关系最近,并聚为一支。对白芨Bs CAS基因的克隆和序列特征分析为进一步阐明BsCAS基因在调控植物甾醇类物质合成途径中的功能提供数据支持。

Cycloartenol synthase(CAS)plays an important regulatory role in the synthesis of phytosterols and triterpenoids.Studying the sequence information of BsCAS gene could lay foundation for the gene function.Based on the transcriptome data of Bletilla striata,the full length CDS of BsCAS gene was obtained by RT-PCR.Bioin-formatics software was used to analyze the physicochemical properties and structural characteristics of BsCAS.Amino acid sequence alignment and phylogenetic analysis of BsCAS were analyzed.The result showed that the BsCAS cDNA contained an open reading frame of 2277 bp nucleotides encoding a 758 amino acids protein.It was predicated that the BsCAS protein was a hydrophilic protein with no transmembrane structure and no signal pep-tide.BsCAS protein had typical DCTAE domain and QW domain,belonging to oxidosqualene cyclases superfami-ly.The phylogenetic comparisons revealed that BsCAS shared high identity with CAS proteins of Dendrobium catenatum and Phalaenopsis equestris,clustered on the same evolutionary branch.The clone and sequence analysis of BsCAS gene provided experimental basis for the study of phytosterol biosynthesis in B.striata.