黄灯笼辣椒多聚半乳糖醛酸酶基因CCaPG的生物信息学和表达分析

Bioinformatical and Expression Analysis of Polygalacturonase Gene from Capsicum chinense

本研究根据Gene Bank已发表的辣椒基因组序列信息,设计引物,利用RT-PCR法从海南黄灯笼辣椒中克隆了多聚半乳糖醛酸酶基因(PG),并命名为CCa PG基因。生物信息学及表达分析结果表明,该基因CDS区全长1 107 bp,编码368个氨基酸,推测为稳定的亲水蛋白,在N端由一条长约25 aa的信号肽;CCa PG蛋白二级结构预测显示,α-螺旋占18.75%,延伸链占37.23%,无规则卷曲占36.41%,β-转角占7.61%。系统进化树分析结果显示,CCa PG与一年生辣椒的亲缘关系最近,达98.37%,其次为美花烟草76.16%。表达量分析发现,CCa PG基因在果实变色期表达量最高,其次为幼果期,最低为绿熟期。本结果可为研究该基因的生物学功能和黄灯笼辣椒果实软化的调控机制奠定理论基础。

In this study, based on the sequence information of pepper genome published on Gene Bank, the full length c DNA of PG gene was obtained from Capsicum chinense L. by RT-PCR and named CCa PG. Analysis of the CCa PG nucleotide sequence revealed that the gene comprises 1 107 nucleotides that encodes a 368 amino acid polypeptide, the bioinformatics analysis results showed that the protein is a hydrophilic protein, in the N terminal has a signal peptide. The secondary structures of CCa PG were mainly α-helix(18.75%), extended strand(37.23%),random coil(36.41%), beta turn(7.61%). With alignment and phylogenetic analysis, which indicated that CCa PG had the highest identity amino acid sequence with Capsicum annuum and Nicotiana sylvestris PG protein, respect98.37% and 76.16%. Quantitative RT-PCR analyses indicated that the expression level of CCa PG was highest in the colour-changed stage, followed by bear fruit stage and lowest in the mature stage. The results provide theoretical basis for further studying the biology function of CCa PG and regulatory mechanism of ripeness in Capsicum chinense L. fruit.