毛竹PheMYB2R-4的克隆与功能分析

Cloning and Functional Analysis of PheMYB2R-4 inPhyllostachys edulis

[目的]研究MYB转录因子家族在毛竹干旱胁迫反应中的重要作用,为毛竹的抗逆改良和分子育种提供基因资源。[方法]从毛竹的基因组数据库中获得PheMYB2R-4的基因序列,利用亚细胞定位和转录活性实验分析基因的分子特性、通过实时荧光定量PCR技术、转基因拟南芥表型分析和逆境相关生理生化指标的测定来确定PheMYB2R-4基因的功能。[结果]毛竹中PheMYB2R-4编码1个305个氨基酸的蛋白PheMYB2R-4,其N端区域有一个保守的R2R3区域,属于R2R3-MYB亚家族。PheMYB2R-4基因的表达受到干旱和盐的显著诱导。PheMYB2R-4是一个核定位蛋白,具转录自激活活性。PheMYB2R-4的过表达提高了干旱胁迫下拟南芥的叶片相对含水量,降低了相对电导率并减少了丙二醛的积累,说明过表达PheMYB2R-4通过提高拟南芥的保水能力和减少氧化损伤来增强转基因拟南芥的耐旱性;同时干旱胁迫下,AtRD22、AtRD29A、AtDREB2A和AtLEA基因的表达量均上调。[结论]MYB转录因子家族中PheMYB2R-4在干旱胁迫应答反应中具有正调控作用,可以提高植物的耐旱性,增强干旱响应基因的表达量。

[Objective]The role of MYB transcription factor family in the drought stress response of Phyllostachys edulis was analyzed to provide candidate genes for stress resistance improvement and molecular breeding of moso bamboo.[Method]In this study,the gene sequence of PheMYB2R-4 was obtained from the genome database of Phyllostachys edulis,and the molecular characteristics of PheMYB2R-4 was analyzed by subcellular localization and transcriptional activity experiments.The function of PheMYB2R-4 was confirmed by qRT-PCR,phenotype analysis of transgenic Arabidopsis thaliana and determination of stress-related physiological and biochemical indicators.[Result]PheMYB2R-4 encoded a protein with 305 amino acids,which had a conservative R2R3 domain in its N-terminal region and belonged to the R2R3-MYB subfamily.The expression of PheMYB2R-4 gene was significantly induced by drought and salt.PheMYB2R-4 was a nuclear localization protein and had transcriptional self-activation activity.The overexpression of PheMYB2R-4 increased the relative water content of Arabidopsis thaliana leaves under drought stress and decreased the relative conductivity and the accumulation of malondialdehyde,indicating that the overexpression of PheMYB2R-4 enhanced the drought tolerance of transgenic Arabidopsis thaliana by improving its water retention capacity and reducing oxidative damage.At the same time,under drought stress,AtRD22,AtRD29A,AtDREB2A and AtLEA were all up-regulated.[Conclusion]PheMYB2R-4 has a positive regulatory role in the response to drought stress,which can improve the drought tolerance of plants and enhance the expression of drought response genes.