缫丝花OSCA基因家族的鉴定与表达分析

Identification and expression analysis of OSCA gene family in Rosa roxburghii Tratt.

OSCA是一类感受外界高渗胁迫的钙离子通道,在植物的胁迫应答中发挥重要作用。为了了解缫丝花(俗名"刺梨",Rosa roxburghii)OSCA(RrOSCA)的结构特征和表达特点,本研究从缫丝花基因组中鉴定出了19个RrOSCA基因家族成员,定位在6条染色体上。通过生物信息学分析发现80%的基因家族成员内含子数量为7~10个,而编码氨基酸在158~1256 aa之间,差别较大;亚细胞定位预测结果显示其主要定位在细胞膜上,与其功能一致。通过基因系统进化分析可将拟南芥(Arabidopsis thaliana)、水稻(Oryza sativa)、苹果(Malus pumila)、草莓(Fragaria×ananassa)、缫丝花的OSCA家族成员可归入4个亚家族,其中RrOSCA家族与草莓OSCA家族的亲缘关系最近。果实发育过程中的转录组测序结果表明,除RrOSCA4外,其余成员的表达均呈现出明显的时间特异性。对其中6个成员进行实时荧光定量PCR分析,发现其均表现出组织特异性,且在花瓣中大量表达;并且这些成员的转录或被外源钙诱导,或被螯合剂乙二醇四乙酸(EGTA)和钙通道抑制剂维拉帕米(verapamil)阻遏,并表现出不同的钙响应敏感性。分析各基因家族成员的启动子序列,发现多种胁迫和激素类响应元件;外源植物生长调节剂处理结果证实除RrOSCA2外,其余被检测成员均受生长素类或水杨酸(SA)诱导。以上结果可为深入揭示缫丝花OSCA基因家族功能及其对激素、Ca^(2+)等因素的响应机制提供参考信息。

In plants,OSCA is a calcium channel that can sense external hyperosmotic stress,and plays an important role in stress response.In order to explore the structure and expression characteristics of OSCA gene family in Rosa roxburghii(RrOSCA),we identified 19 members of RrOSCA gene family from R.roxburghii genome,which are located on 6 chromosomes.Bioinformatics analysis reveals that 80%of the gene family members have 7–10 introns and encode from 158 up to 1256 amino acids.Subcellular localization analysis predicts that they are mainly localized on the cell membrane,which is consistent with their functions.Phylogenetic analysis suggested that the OSCA families of Arabidopsis thaliana,rice(Oryza sativa),apple(Malus pumila),strawberry(Fragaria×ananassa)and R.roxburghii could be classified into four subfamilies,and the RrOSCA family has the closest homology with that of strawberry.The results of RNA sequencing data during fruit development showed that the expression of all the members presented significant temporal specificity except for RrOSCA4.Furthermore,real-time quantitative PCR analysis of six members revealed that they all exhibited tissue specificity and were abundantly expressed in the petals.The transcription was either induced by exogenous calcium or repressed by the chelator ethylene glycol tetraacetic acid(EGTA)and the calcium channel inhibitor verapamil,which showed different calcium response sensitivities.Promoter sequence analysis demonstrates that each gene member contains various stress and hormone response elements.The results of different exogenous plant growth regulator treatments confirmed that all the tested genes,except for RrOSCA2,were induced by auxins or salicylic acid.The results further reveal the function of the OSCA gene family in R.roxburghii and its response mechanism to hormones,Ca^(2+) and other factors.