拟南芥PAL基因家族鉴定及表达模式分析

Identification and expression pattern analysis of PAL family genes in Arabidopsis thaliana

摘要:

为研究苯丙氨酸解氨酶（PAL）作为苯丙烷类代谢途径的关键酶，在植物响应环境胁迫过程中的重要作用，本研究利用HMMER、Pfam与SMART等工具，从拟南芥全基因组中筛选获得 9 个PAL成员，分析其编码酶蛋白的理化性质、二级结构与保守基序等信息.同时，结合转录组与定量PCR分析PAL成员在干旱与盐胁迫条件下的表达模式.结果表明，拟南芥PAL成员的二级结构主要由α-螺旋和无规则卷曲组成；亮氨酸和丙氨酸为含量较高的氨基酸残基；拟南芥PAL成员含有 20 种不同的保守基序，其中motif6含有ASG活性位点，为所有PAL成员所共有；较多PAL成员具有光响应、激素响应、胁迫响应和生长发育相关的顺式调控元件.转录组学与定量PCR分析发现，AT3G53260.1、AT3G53260.2与AT3G47660.1的mRNA表达水平在干旱与盐胁迫后发生显著变化，推测这 3 条基因可能参与拟南芥对干旱及盐胁迫的响应过程，表明PAL基因在调控植物生长发育与非生物胁迫响应过程中发挥重要作用.

Abstract:

To study the important role of phenylalanine ammonia-lyase, as a key enzyme in the phenylpropanoid metabolic pathway, in plant response to environmental stresses, the genomic information of Arabidopsis thaliana was downloaded from Phytozome and the PAL members were further identified by HMMER, Pfam and SMART tools. The physicochemical properties, secondary structure and conserved motifs of nine PAL proteins were analyzed. The results showed that the secondary structure of PAL members in Arabidopsis thaliana was mainly composed of α -helix and random curl. Leu and Ala were the most abundant amino acid residues. There were 20 different conserved motifs in the PAL gene family of Arabidopsis thaliana, among which motif 6 containing active site ASG appeared in all PAL genes. The analysis of cis-acting elements showed that the PAL gene family contained many elements related to light response, hormone response, stress response and growth and development. The mRNA expression levels of AT3G53260.1, AT3G53260.2 and AT3G47660.1 showed obvious changes based on transcriptome analysis, and the corresponding tendency was verified by further real-time PCR. Therefore, these 3 genes might be involved in the response to drought and salt stress of Arabidopsis thaliana. These results indicate that PAL genes play an important role in regulating plant growth and development and abiotic stress response.