茶树DIR基因家族鉴定及在炭疽病胁迫下表达模式分析

Identification and expression pattern of DIR gene family in Camellia sinensis under anthracnose stress

关键词:  茶树，DIR基因家族，结构特征，理化特性，表达分析

Key words:  Camellia sinensis, DIR gene family, structural features, chemical and physical propertie, expression analysis

摘要:

Dirigent（DIR）蛋白在植物体内参与木质素和木脂素的生物合成过程，在植物生长发育和胁迫应答等过程中发挥重要作用。该研究在茶树（Camellia sinensis）全基因组中筛选到40个CsDIR家族基因，并对该基因家族的理化性质、系统进化树、保守基序、染色体定位、顺式作用元件结构特征和茶炭疽病胁迫下基因表达模式进行分析。结果表明：（1）进化分析表明，茶树DIR基因可分为3个亚家族，其启动子区域包含生长素、脱落酸、创伤和病原菌等响应元件。（2）蛋白结构及蛋白保守结构域分析，40个CsDIR蛋白均含有由8条反向平行β-折叠组成的β-桶。39个CsDIR蛋白含有Dirigent结构，1个CsDIR蛋白含有Dirigent superfamily结构域。（3）染色体定位及共线性分析结果表明，40个CsDIR基因分布在10条染色体和5个不同的Contig上，CsDIR基因家族中有12对串联重复基因和4对共线性基因。（4）茶炭疽病胁迫下12个CsDIR家族基因的表达模式分析表明，12个CsDIR家族基因均响应茶炭疽病胁迫。该研究为进一步研究DIR基因家族在茶树应对生物胁迫时的功能提供参考。

Abstract:

Dirigent (DIR) proteins play crucial roles in lignin and lignan biosynthesis, significantly influencing plant growth, development and stress responses. This study identified 40 CsDIR genes through genome-wide screening in Camellia sinensis, and analysed for physicochemical properties, phylogenetic tree, conserved motifs, chromosomal localisation, cis-acting element structural features, and gene expression patterns of DIR gene family under tea anthracnose stress. The results demonstrate that (1) Phylogenetic analysis classifies the CsDIR genes into three subfamilies, and their promoter regions contain response elements for auxin, abscisic acid, wounding and pathogens. (2) Analysis of protein structures and conserved domains confirme that 40 CsDIRs contain a β-barrel composed of eight antiparallel β-strands. 39 CsDIRs possess a Dirigent domain, while one contains a Dirigent superfamily domain. (3) Results of chromosomal localization and collinearity analysis indicate that the 40 CsDIR genes distribute across 10 chromosomes and 5 distinct contigs. Within CsDIR gene family, we identify 12 pairs of tandemly duplicated genes and 4 pairs of collinear genes. (4) Expression pattern analysis of 12 CsDIR genes under tea anthracnose stress demonstrates that all 12 CsDIR genes uniformly respond to tea anthracnose stress. This study provides a foundation for future research on the function of DIR gene family in response to biotic stresses in tea plants.