摘要：

赤霉素氧化酶基因(GAox)是赤霉素合成和调控的关键酶,其通过调节植物活性GA水平调控植物株高。为了解析蓖麻赤霉素氧化酶基因(RcGAox),利用生物信息学分析方法对RcGAox进行全基因组鉴定,并分析其理化性质、保守结构域、系统发育、基因上游2 kb启动子区域顺式作用元件预测,通过蓖麻表达数据库以及外源赤霉素和多效唑处理2个蓖麻品种的顶端嫩茎转录组测序分析RcGAox基因表达模式。结果表明:蓖麻共有30个赤霉素氧化酶基因,其中7个RcGA2ox、4个RcGA3ox、19个RcGA20ox,蛋白质分子质量在26.12~44.31 ku,等电点预测值在5.06~7.82,内含子个数为1~2个;蛋白结构域分析保守基序Motif 1、Motif 2、Motif 4存在30条蛋白序列中;系统进化分析将RcGAox基因分为5个不同的亚群:Ⅰ、Ⅱ、Ⅲ、Ⅳ和C20 GA2ox,其中Ⅰ、Ⅱ、Ⅲ分别对应GA2ox、GA3ox、GA20ox;启动子顺式作用元件预测光反应相关的顺式元件数量最多,且在预测区域均匀分布,18个基因含1~2个赤霉素相关元件;蓖麻RcGAox在胚乳、雄花、叶片中特异表达的基因分别有7,2,1个,转录组测序结果有5个基因在嫩茎中表达,推测RcGA2ox7、RcGA20ox1和RcGA20ox14可能是参与赤霉素合成途径来调控蓖麻株高的主要基因,且通过调控植物体内活性赤霉素水平来响应外源激素对株高的作用。

关键词: 蓖麻, 赤霉素氧化酶, 分子特征, 生物信息学, 基因表达

Abstract:

Gibberellin oxidase gene(GAox)is a key enzyme in the synthesis and regulation of gibberellin,and effect on plant height through regulating active GA level.To analyze the gene of gibberellin oxidase in castor,we identified gibberellin oxidase gene(RcGAox)from the castor bean whole genome by bioinformatics,and analyzed physicochemical properties,conserved domain,phylogeny,promoter cis-acting element.The RcGAox gene expression pattern was analyzed by tissue specific expression of online database and apical tender stem transcriptome sequencing.A total of 30 gibberellin oxidase genes were identified from the castor genome,including 7 RcGA2ox,4 RcGA3ox,and 19 RcGA20ox.The molecular weight was ranged from 26.12 to 44.31 ku,and the isoelectric point was ranged from 5.06 to 7.82.Gene structure analysis showed that the number of introns was ranged from 1 to 2.Protein conserved domain analysis showed that all the genes shared conserved Motif 1,Motif 2 and Motif 4.Phylogenetic analysis showed that RcGAox genes were clustered into five subfamilies Ⅰ,Ⅱ,Ⅲ,Ⅳand C20 GA2ox,and subfamiliesⅠ,Ⅱ,Ⅲ correspond to GA2ox,GA3ox and GA20ox respectively.Promoter cis-acting element prediction showed that light-related elements had largest number and uniform distribution in predicting region,and 18 genes had 1 to 2 gibberellin-related element.There were 7,2,and 1 RcGAox genes specifically expressed in endosperm,male flowers and leaves respectively.Transcriptome sequencing showed that 5 genes were expressed in tender stems.It was supposed that RcGA2ox7,RcGA20ox1 and RcGA20ox14 might be the main gene involved in gibberellin synthesis pathway to regulate castor plant height.These results might provide theoretical basis for further studies on the RcGAox gene function in castor bean.

Key words: Castor bean, Gibberellin oxidase, Molecular characteristics, Bioinformatics, Gene expression