茶树OSCA基因家族的鉴定及表达分析

Identification and Expression Analysis of OSCA Gene Family in Tea Plant

钙通透性阳离子通道蛋白(OSCA)在植物调节高渗胁迫中发挥着重要作用。为了解OSCA基因家族在茶树响应干旱胁迫中的作用,本研究基于茶树全基因组数据对OSCA基因家族进行鉴定,分析CsOSCAs基因和蛋白结构以及启动子顺式作用元件,并对CsOSCAs在茶树不同组织、不同抗旱性品种间和干旱胁迫下的表达模式进行分析。结果表明:茶树基因组包含12个OSCA基因家族成员,分别命名为CsOSCA1~CsOSCA12;CsOSCAs基因编码的氨基酸序列长度为667~831 bp,蛋白分子量在76630.55~93563.99 kDa之间,等电点在6.15~9.33之间,含有9~12个跨膜结构域,均含有特征保守结构域DUF221,根据系统进化关系可以分为4个亚族;10个CsOSCAs基因定位于茶树7条染色体上,2个CsOSCAs基因定位于未锚定染色体的contig上;CsOSCAs基因编码的蛋白二级结构含有32%~38%的跨膜结构和60%~68%的α-螺旋;CsOSCAs基因具有组织表达特异性,CsOSCA2、CsOSCA3、CsOSCA11、CsOSCA12基因在干旱敏感的品种CN98中的表达量显著高于其他2个耐旱品种,9个基因响应PEG胁迫,其中CsOSCA2、CsOSCA3、CSOSCA5、CsOSCA8、CsOSCA10和CsOSCA12受干旱胁迫强烈诱导;进一步分析启动子顺式作用元件显示,6个基因含有干旱诱导响应元件,11个基因含有脱落酸响应元件。由此推测茶树OSCA基因家族在茶树响应干旱胁迫中发挥着重要的作用,此研究为茶树OSCA基因功能分析与茶树抗逆性研究提供参考。

The hyperosmotic Ca^(2+)channel protein OSCA is crucial for controlling hyperosmotic stressors in plants.To understand the role of the OSCA gene family in tea plant response to drought stress,this study was conducted to identify the OSCA gene family based on the whole genome data of tea plant and analyze the gene and protein structures and promoter cis-acting element,and analyze the expression patterns of CsOSCAs in different tissues of tea plant,among different drought-resistant varieties and under drought stress.The results showed that the tea plants genome contained 12 members of the OSCA gene family,named CsOSCA1‒CsOSCA12.The amino acid sequences encoded by the CsOSCAs were 667‒831 bp in length,with protein molecular weight ranging from 76630.55 kDa to 93563.99 kDa and isoelectric points ranging from 6.15 to 9.33,containing 9‒12 transmembrane structural domains,all containing the characteristic conserved structural domain DUF221,which could be divided into four subfamilies based on phylogenetic relationships.Ten CsOSCAs were localized to seven chromosomes of Camellia sinensis and two CsOSCAs were local-ized to the contig of unanchored chromosomes.The secondary structure of the CsOSCAs contained 32%‒38%trans-membrane structure and 60%‒68%α-helix.The CsOSCAs were tissue expression specific,and CsOSCA2,CsOSCA3,CsOSCA11,and CsOSCA12 were significantly higher in the drought-sensitive variety CN98 than those in the other two drought-tolerant varieties.Nine genes were responded to PEG stress,among which CsOSCA2,CsOSCA3,CSOSCA5,CsOSCA8,CsOSCA10,and CsOSCA12 were strongly induced by drought stress.Six genes included drought-inducible response elements,and 11 genes contained abscisic acid response elements,according to further examination of the promoter cis-acting elements.It is hypothesized that the OSCA gene family of tea plants play an important role in the response to drought stress,and this study would provide a reference for the functional analysis and stress resistance of OSCA gene in tea plant.