苎麻植物螯合肽合成酶(BnPCS1)基因的克隆和表达

根据苎麻转录组测序中的PCS基因片段,利用RT-PCR结合RACE技术从中苎1号中克隆获得了该基因的全长cDNA序列,命名为BnPCS1。该基因的cDNA序列全长为1956 bp,其中开放读码框长1512 bp,编码503个氨基酸,预测其分子量和等电点分别为56.02 kD和7.01。与长喙田菁(ACT87974)、百脉根(Q2TSC7)、狼牙刺(AFM38979)、荷花(BAN08523)和杜梨(AEY68568)的PCS氨基酸序列相似性分别为74%、73%、75%、73%和77%。荧光定量PCR分析表明,BnPCS1在根、茎、茎尖、幼叶、成熟叶中均有表达,其中在成熟叶中的表达量最高,茎中表达量最低,并且该基因受镉和ABA诱导上调表达。BnPCS1基因的克隆将为苎麻抗重金属分子育种和进一步的功能分析奠定基础。

Cloning and Characterization of the BnPCS1 Gene from Ramie (Boehmeria nivea L.)

The contamination of heavy metals by mining and combustion of fossil fuel has brought about significant deleterious consequences not only to environment but also to human health. Ramie(Boehmeria nivea L.) is a China originated fiber crop that has great ability to tolerate and accumulate heavy metals. To explore the mechanism of ramie to tolerate cadmium, we isolated and analysed a novel gene(BnPCS1) exhibiting high homology with phytochelatin synthase gene(PCS) from Zhongzhu 1 ramie by RT-PCR and RACE methods. The full length sequence and the ORF of BnPCS1 gene is 1 888 bp and 1 512 bp, respectively, which encodes 503 amino acids(56.02 kDa) with a pI value of 6.76. The similarity comparison revealed that the deduced amino acid sequence shares 74%, 73%, 75%, 73% and 77% of homology with Lotus japonicas(Q2TSC7), Nelumbo nucifera(BAN08523), Pyrus betulifolia(AEY68568), Sesbania rostrata(ACT87974) and Sophora viciifolia(AFM38979). Real-time quantitative PCR was used to analyze expression pattern of BnPCS1 in different organs and under Cd, ABA and SA treatment. We found that BnPCS1 was mainly expressed in mature leaf and highly induced in leaf by Cd and ABA treatment, respectively. These results indicated that BnPCS1 may be involved in response of ramie plants to Cd stress. In this study, we succeeded cloned an phytochelatin synthase gene(BnPCS1) and studied in primary level, which established the foundation for the future study in the mechanism of ramie to heavy metal Cd stress.