连翘2个DIR基因的分子特征与表达分析

Molecular Characterization and Expression of Two Dirigent Genes from Forsythia suspensa

目的:克隆连翘DIR基因并分析其分子特征和表达特性。方法:克隆两条连翘的DIR基因全长序列,并采用实时荧光定量PCR法对该基因在连翘不同组织以及茉莉酸甲酯诱导下的表达进行分析。结果:克隆得到两个DIR基因(FsDIR1,MF168408;FsDIR2,MF168409),长度分别为558 bp和564 bp,编码氨基酸数目分别为185和187;系统进化树分析表明,FsDIR1属于DIR-a亚家族,FsDIR2属于DIR-b/d亚家族。连翘不同组织实时荧光定量PCR结果表明FsDIR1和FsDIR2在花瓣中表达量最低,而在雌蕊中最高。茉莉酸甲酯诱导后,叶片中连翘苷和连翘酯苷A含量升高,但FsDIR1和FsDIR2的表达量均显著下降。结论:本研究克隆了两个连翘DIR基因,为研究DIR基因在连翘木脂素类化合物生物合成及参与植物的抗性反应中的功能奠定了基础。

Objective： To clone the DIR gene from Forsythia suspensa and analyze the molecular characterization and expression profiles of the gene. Methods： Two full-length c DNA encoding DIR were cloned from Forsythia suspensa,and the expression profiles revealed by QPCR under different tissues and methyl jasmonate（ Me JA） treatments were compared. Results： The full-length c DNA cloned（ FsDIR1,MF168408; FsDIR2,MF168409） had a 558 bp and 564 bp open reading frame,encoding a protein of 185 and 187 amino acids,respectively. Phylogenetic tree analysis indicated that FsDIR1 belonged to the DIR-a subfamily and FsDIR2 belonged to the DIRb/d subfamily. Tissue-specific expression analysis of FsDIR1 and FsDIR2 in all tested tissues showed lowest expression in petals. Higher expressions were observed in pistils. After the induction of Me JA,the production of phillyrin and forsythoside were increased,however the relative express of FsDIR1 and FsDIR2 was signally inhibited. Conclusion： The FsDIR1 and FsDIR2 gene are isolated from Forsythia suspensa. The results of this study provides a foundation for functional characterization of DIR gene involved in lignan biosynthesis pathway and resistance response of Forsythia suspensa.