青花菜多聚半乳糖醛酸酶基因BoPGX3的克隆及盐胁迫下的表达特征分析

Cloning of Broccoli Polygalacturonase Gene BoPGX3 and Analysis of Its Expression Characteristics under Salt Stress

多聚半乳糖醛酸酶(PG)可降解细胞壁,从而降低植物抵抗能力。为了解青花菜PG基因响应盐胁迫的分子机制,以青花菜自交系‘WN12-95B’为试验材料,提取青花菜的总RNA并合成cDNA,克隆PG基因,并检测其在盐胁迫下的表达特征。结果表明:青花菜BoPGX3基因序列全长1476 bp,推导编码491个氨基酸,相对分子量为53.44 kD,等电点为5.84。系统进化分析表明,青花菜BoPGX3与羽衣甘蓝、甘蓝、白菜、萝卜和花椰菜的PG基因亲缘关系较近。荧光定量PCR结果显示,BoPGX3基因受盐胁迫诱导表达,处理3 h后相对表达量达到初始表达量的2.9倍,处理12 h时相对表达量下降至初始表达量的1.4倍。综上,青花菜BoPGX3基因参与了盐胁迫的响应,并可能在此过程中发挥着重要的作用。

Polygalacturonase(PG)can degrade the cell wall to reduce resistance in plant.In order to understand the molecular mechanism of PG gene response to salt stress in broccoli,the total RNA was extracted and cDNA was synthesized to clone the PG gene of broccoli by taking the inbred line'WN12-95B'as experimental material.Meanwhile the expression characteristics of PG gene were also detected under salt stress.The results showed that the total length of BoPGX3 gene sequenc was 1476 bp in broccoli,deduced encode 491 amino acids,with a relative molecular weight of 53.44 kD and an isoelectric point of 5.84.Phylogenetic analysis showed that BoPGX3 had close genetic relationship with Brassica oleracea var.acephala,Brassica oleracea,Brassica rapa subsp.pekinensis,Raphanus sativus and Brassica oleracea L.var.botrytis.The results of fluorescent quantitative PCR showed that the expression of BoPGX3 gene could be induced with salt stress.After 3 hours of treatment,the relative expression level increased to 2.9 times,and decreased 1.4 times at 12 h after treatment.BoPGX3 can involve in the response to salt stress in broccoli,and may play important roles in this process.