杠柳天然橡胶合成相关R2R3−MYB基因克隆及表达分析

Cloning and Expression Analysis of R2R3−MYB Genes Involved in Natural Rubber Synthesis in Periploca sepium

  • 摘要: 首次克隆了杠柳中调控天然橡胶生物合成途径的R2R3−MYB基因,为杠柳天然橡胶生物合成调控机制的研究提供候选基因。利用生物信息学的方法,对杠柳的基因组数据进行分析,发现122条R2R3−MYB基因。通过构建系统进化树、氨基酸多序列比对、保守结构域和三级结构分析,确定杠柳中可能参与调控天然橡胶合成的R2R3−MYB基因,并进行基因在杠柳中的组织特异性表达分析。结果表明:PsMYB79PsMYB102PsMYB159PsMYB178与巴西橡胶树 HbMYB在同一分支上,均具有典型的R2R3−MYB结构域及SHAQKYF保守基序,而且氨基酸之间序列相似性分别为72.5%、64.5%、61.6% 和57.8%。RT− PCR分析结果表明,4个基因在乳胶形成的部位中均表达,其中PsMYB79PsMYB178在根中表达最强,PsMYB102在幼叶中表达强烈, PsMYB159在根、茎、幼叶和老叶中普遍表达。因此推测杠柳R2R3−MYB转录因子家族中PsMYB79PsMYB102PsMYB159PsMYB178基因可能参与调节植物不同组织器官中天然橡胶生物合成过程。

     

    Abstract: In this study, we first investigate and clone the R2R3−MYB genes involved in regulate of the natural rubber pathway in Periploca sepium, providing useful genes for the regulation of natural rubber biosynthesis. Using the method of bioinformatics, 122 R2R3−MYB genes were found by analyzing the genomic data of P. sepium. Through the construction of phylogenetic tree, amino acid multi sequence alignment, conserved domain and protein tertiary structure analysis, the R2R3−MYB gene that may be involved in the regulation of natural rubber synthesis was determined, and the tissue-specific expression of the gene was analyzed. The results showed that PsMYB79, PsMYB102, PsMYB159 and PsMYB178 belongs in the same evolutionary branch with HbMYB, that controlling natural rubber, and alignment of the protein sequence of these genes revealed a highly conserved R2R3 repeat domain and SHAQKYF conserved motif. The amino acid sequence similarity between these genes and HbMYB gene was 72.5%, 64.5%, 61.6% and 57.8% respectively. RT−PCR analysis showed that the 4 genes were expressed in the site of latex formation, among which PsMYB79 and PsMYB178 were the strongest in roots, PsMYB102 was strongly expressed in young leaves, and PsMYB159 was generally expressed in roots, stems, young leaves and old leaves. Therefore, it is speculated that PsMYB79, PsMYB102, PsMYB159 and PsMYB178 genes in the R2R3−MYB transcription factor family of P. sepium may be involved in the regulation of natural rubber biosynthesis in different tissues and organs of plants.

     

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