太子参分解代谢关键酶8′羟化酶基因的克隆及生物信息学分析.docVIP

太子参分解代谢关键酶8′羟化酶基因的克隆及生物信息学分析 　　[摘要] ABA 8′羟化酶是脱落酸（abscisic acid，ABA）分解代谢中的关键酶基因之一。采用同源检索的方法从太子参转录组数据库中获得7个ABA 8′羟化酶（abscisic acid 8′-hydroxylase）基因家族成员，对各家族成员进行转录分析组数据以及ABA 8′羟化酶关键基因ABA8ox1编码区（coding sequence，CDS）的克隆与生物信息学分析。ABA8ox1基因CDS全长1 401 bp，编码480个氨基酸残基，等电点为8.55，相对分子质量为53 kDa，跨膜分析显示其为膜蛋白，1～21个氨基酸残基位于胞内，22～466个氨基酸残基位于胞外。转录组数据分析及定量PCR技术共同证明ABA8ox1在块根的韧皮部及须根中有较高的表达。多序列比对及聚类分析显示与其他植物CYP707A蛋白具有较高的同源性，且与模式植物拟南芥中ABA分解关键基因AtCYP707A1和AtCYP707A3聚为一类。该研究为太子参块根膨大及对逆境胁迫响应的分子机制奠定基础。 　　[关键词] 太子参；脱落酸；降解；ABA 8′羟化酶；表达分析 　　[Abstract] Abscisic acid 8′-hydroxylase was one of key enzymes genes in the metabolism of abscisic acid （ABA）. Seven menbers of abscisic acid 8′-hydroxylase were identified from Pseudostellaria heterophylla transcriptome sequencing results by using sequence homology. The expression profiles of these genes were analyzed by transcriptome data. The coding sequence of ABA8ox1 was cloned and analyzed by informational technology. The full-length cDNA of ABA8ox1 was 1 401 bp，with 480 encoded amino acids. The predicated isoelectric point （pI） and relative molecular mass （MW） were 8.55 and 53 kDa，respectively. Transmembrane structure analysis showed that there were 21 amino acids in-side and 445 amino acids out-side. High level of transcripts can detect in bark of root and fibrous root. Multi-alignment and phylogenetic analysis both show that ABA8ox1 had a high similarity with the CYP707As from other plants，especially with AtCYP707A1 and AtCYP707A3 in Arabidopsis thaliana. These results lay a foundation for molecular mechanism of tuberous root expanding and response to adversity stress. 　　[Key words] Pseudostellariae Radix；abscisic acid；degradation；abscisic acid 8′-hydroxylase；expression analysis 　　doi：10.4268/cjcm 　　自然界中许多植物具有膨大的根茎器官，在对不同环境的适应过程中具有重要作用[1]。地黄[2]、麦冬[3]等地下膨大部分为块根，由不定根或侧根膨大形成；马铃薯[4]地下膨大部分为根茎，由匍匐茎顶端膨大形成。植物的生长发育及形态建成受到植物内源激素系统的调控，通过控制不同激素的比例及水平来影响地上部茎叶及地下部根系的发育过程[5-6]。研究表明，植物激素在植物块根（块茎）的发育过程中具有重要作用。细胞分裂素（cytokinin，CTK）[7]、生长素（indole-3-ac