摘要：

扩展蛋白(EXP)可以调节细胞壁组分间松弛度和增强细胞壁的柔韧性,在植物适应环境胁迫过程中起着关键作用。为探究蓝花耧斗菜EXP家族成员特征及其在盐胁迫下表达模式,挖掘蓝花耧斗菜耐盐基因,利用生物信息学方法对蓝花耧斗菜AcEXP家族进行全基因组鉴定及分析,并通过RNA-seq表达数据和qRT-PCR分析其在盐胁迫下的表达模式。结果表明,蓝花耧斗菜全基因组包含27个EXP基因,分布于6条染色体及1个scaffold上;蛋白质二级结构以β-折叠和无规则卷曲为主;27个EXP均定位于细胞壁。系统发育树显示,AcEXP家族成员被划分为4个亚家族(EXPA、EXPB、EXLA、EXLB),同一亚族成员具有相似的基因结构和蛋白保守基序。AcEXP的启动子区域富含多个植物激素响应元件和胁迫响应元件。利用转录组数据,对盐胁迫下AcEXP的表达模式分析表明,21个EXP响应盐胁迫,在根系和叶片中的表达模式存在差异。AcEXPA8/9/12,AcEXPB1、AcEXLB1、AcEXLB2在叶片和根系中均差异表达,且qRT-PCR结果进一步验证了AcEXP基因在盐胁迫下的表达模式。该研究全面分析了蓝花耧斗菜EXP基因家族成员的基本特征及在盐胁迫下的表达变化,初步证明AcEXPA8/9/12、AcEXPB1、AcEXLB1、AcEXLB2参与了盐胁迫应答过程并作出积极响应。

关键词: 蓝花耧斗菜, 扩展蛋白, 全基因组鉴定, 盐胁迫, 表达分析

Abstract:

Expansin (EXP) plays a crucial role in plant adaptation to environmental stress by regulating the relaxation of cell wall components and enhancing flexibility.The aim of this study was to investigate the characteristics of the EXP family members and their expression patterns under salt stress,and to explore the salt tolerance genes in Aquilegia coerulea.Genome-wide identification and analysis of the AcEXP family of Aquilegia coerulea was using bioinformatics methods and its expression pattern under salt stress was analysed using RNA-seq expression data and qRT-PCR.The results revealed that the entire genome of the Aquilegia coerulea contained 27 EXP genes,distributed across six chromosomes and one scaffold.The secondary structure of proteins was dominated by β-sheet and random coil.The majority of the proteins were hydrophobic,and all 27 EXPs were found in the cell wall.The phylogenetic tree showed that members of the AcEXP family were classified into four subfamilies:EXPA,EXPB,EXLA and EXLB.Members of the same subfamily possessed similar gene structure and protein conserved motifs.The AcEXP genes contained multiple elements that responded to phytohormones and stress.The transcriptome data was used to analyze the expression pattern of AcEXP under salt stress.Twenty-one EXPs responded to salt stress,but the expression patterns were different in roots and leaves.AcEXPA8/9/12,AcEXPB1,AcEXLB1 and AcEXLB2 were differentially expressed in leaves and roots.The qRT-PCR results further verified the expression pattern of AcEXP genes under salt stress.It comprehensively analyse the basic characteristics of the EXP gene family members of Aquilegia coerulea and expression changes under salt stress.The study preliminarily demonstrates that AcEXPA8/9/12,AcEXPB1,AcEXLB1 and AcEXLB2 are involved in the salt stress response process and responded positively.

Key words: Aquilegia coerulea, Expansin, Genome-wide identification, Salt stress, Expression analysis