马尾松R2R3-MYB基因特征及进化和表达分析

Characteristics, evolutionary and expression analysis of R2R3-MYB genes in Pinus massoniana

关键词:  马尾松, R2R3-MYB, 生物信息学分析, 非生物胁迫, 基因表达

Key words:  Pinus massoniana, R2R3-MYB, bioinformatics analysis, abiotic stress, gene expression

摘要:

MYB类转录因子在植物生长发育、代谢、应答生物胁迫和非生物胁迫的响应等生物过程发挥重要作用。为探究马尾松R2R3-MYB基因结构及功能,该研究以转录组数据为研究区域,从中筛选获得了17个马尾松R2R3-MYB基因,利用生物信息学对基因进行理化性质、系统进化树等分析,同时利用荧光定量PCR技术分析基因的组织特异性以及在花发育时期和非生物胁迫下的表达模式。结果表明:(1)17个PmMYBs亚细胞定位于细胞核,均无跨膜结构,且均含有Motif1、Motif2保守基序。系统发育进化树将马尾松PmMYBs划分为9个亚家族,且与火炬松、白云杉等裸子针叶植物关系较近。(2)17个基因均属于组成型表达,但在不同组织的表达量不同; 所有基因均参与了花发育和非生物胁迫,不同基因在花发育不同时期的表达存在差异,有7个基因可能参与了雌雄性状转变; 大部分基因响应非生物胁迫上调表达,但响应胁迫的时间存在差异; 少数基因在胁迫中下调表达,尤其是PmMYB11基因在所有胁迫中均明显下调表达。该研究较系统地分析了马尾松R2R3-MYB基因的结构特征、系统进化及其在花发育时期和非生物胁迫下的表达模式,为深入探究马尾松R2R3-MYB基因的功能及逆境响应机制提供了参考。

Abstract:

MYB transcription factors play important roles in plant growth and development,metabolism,responses to biotic and abiotic stresses. In order to explore the structure and function of R2R3-MYB genes in Pinus massoniana, we identified 17 R2R3-MYB genes based on the transcriptome dataset of P. massoniana, and then investigated their physical and chemical properties, phylogenetic relations, gene tissue specificity with qRT-PCR, and expression patterns of these genes in the development process of flower organs and under different abiotic stresses. The results were as follows:(1)Seventeen PmMYBs subcellular were predicted to locate in cell nucleus, without transmembrane structure. They all contained Motif1 and Motif2 conserved motifs. These 17 PmMYBs genes could be divided into nine subgroups according to phylogenetic analysis, which were closely related to gymnosperms such as Pinus taeda and Picea glauca.(2)The expression patterns of PmMYBs genes in different tissues and under salt stress, drought stress, lead stress and low temperature stress were validated by qRT-PCR. As a result, a total of 17 genes were constitutive expressed, but the expression levels were different in different tissues. All genes appeared to be involved in flower development. Seven MYB genes seemed to be involved in the transformation of male and female traits as they were differently expressed in different stages of flower development. Moreover, those genes may also be involved in abiotic stress responses, as most of the genes were up-regulated under abiotic stress. Their unique expression patterns may suggest that they function at different stages of stress. A few genes were down-regulated under stress, especially PmMYB11 gene. This study systematically analyze the characteristics, evolutionary and expression patterns of R2R3-MYB genes in Pinus massoniana during flower development and abiotic stress, and provides a reference for further study on the function and stress response mechanism of R2R3-MYB gene in P. massoniana.