麻疯树JcCBF3基因的克隆及其抗寒功能初探

Cloning of JcCBF3 gene in Jatropha curcas and its functional analysis of cold tolerance

摘要:

从麻疯树中克隆到一个CBF3基因，命名为JcCBF3，ORF全长678bp，编码 225个氨基酸；其氨基酸序列具有典型的CBF蛋白特征；氨基酸序列同源性比对结果表明JcCBF3与其他物种CBF序列具有较高的同源性，其中与木薯和橡胶树的相似度最高，达到79%和74%.利用RT-qPCR分析低温胁迫下JcCBF3基因的表达谱，结果表明其受低温诱导，于12小时达峰值，为对照的62倍，说明该基因强烈响应低温.将JcCBF3基因构建到植物过表达载体pBI121上并成功转化烟草.低温处理下对照及转基因烟草幼苗的游离脯氨酸含量和超氧化物歧化酶活性均增强，但转基因烟草幼苗增加幅度要大于对照.同时JcCBF3基因的过表达增强了含有CRT/DRE元件的下游抗性基因的表达.初步研究表明 JcCBF3基因在植物抗寒机制中扮演重要角色，其可作为麻疯树基因工程育种的一个备选基因.

Abstract:

A CBF3 gene was isolated from Jatropha curcas named JcCBF3. The full length of open reading frame（ORF）was 678 bp, encoding 225 amino acids. The amino acids sequence of JcCBF3 owned the characteristics of CBF protein. The amino acids sequences also had highly homologous with CBF genes of other plants, reached 79% with Manihot esculenta, and 74% with Hevea brasiliensis respectively. RT-qPCR result revealed that JcCBF3 was induced by low temperature . After 12 hours , the transcriptional level of JcCBF3 raised maximum 62 folds than the control, suggesting its drastic response to cold stress in Jatropha curcas. JcCBF3 was constructed into plant expression vector pBI121 and obtained the transgenic tobacco plants. At the low temperature treatment, free proline and superoxide dismutase in transgenic tobacco and the control were all increased, and that of transgenic tobacco were higher than that of normal tobacco plant. Overexpression of JcCBF3 in transgenic tobacco plants enhanced the expression of downstream genes containing CRT/ DRE elements. This study not only proves the cold resistance roles of JcCBF3, but also presents a candidate gene engineering for improvement of cold resistance in Jatropha curcas.