扁桃MYB46转录因子基因的克隆及其表达模式分析

Cloning and expression patterns analysis of MYB46 transcription factor gene in almond

为初步探讨扁桃内果皮薄厚差异形成的机理及MYB46转录因子基因在扁桃内果皮木质素生物合成途径中的作用,本研究以薄壳‘纸皮’和厚壳‘长石头’2个扁桃品种为供试材料,测定内果皮厚度和木质素含量并分析两者的关系。利用RT-PCR结合RACE技术克隆MYB46转录因子基因,并利用实时荧光定量PCR技术分析其表达模式。序列分析结果表明,AcMYB46-z和AcMYB46-c基因全长均为1 380 bp,ORF均为1 017 bp,均编码338个氨基酸,蛋白的相对分子质量分别为37.36和38.77 kDa。推测AcMYB46-z和AcMYB46-c氨基酸序列N端均含有2个高度保守结构域SANT,表明其均属于R2R3类转录因子。系统进化树分析结果AcMYB46-z和AcMYB46-c分别与桃、梅聚为一类。通过qRT-PCR技术对MYB46转录因子基因的时空表达模式进行研究,发现在2个扁桃品种各个发育时期均有表达。相关性分析结果表明,2个扁桃品种的内果皮厚度与木质素含量均呈极显著正相关。推测MYB46转录因子基因参与调控扁桃内果皮木质素的代谢。

To elucidate the mechanism of difference in the formation of almond endocarp thickness and the function of MYB46 transcription factor gene in lignin biosynthesis pathway, we determined thickness and lignin content in the endocarp of two almond varieties, ‘Zhipi＇ and ‘Changshitou＇, and analyzed the relationship between them. MYB46 gene was cloned by RT-PCR combined with the RACE technology, and its expression pattern was analyzed. The results of sequence analysis showed that both AcMYB46-z and AcMYB46-c gene had total length of 1 380 bp, including 1 017 bp ORF, which encoded 338 amino acids. The relative molecular weight of the proteins were 37.36 and 38.77 kDa. Both AcMYB46-z and AcMYB46-c belonged to R2R3 transcription factor, with two highly conserved SANT domains at their N terminal. The results of phylogenetic tree analysis showed that AcMYB46-z and AcMYB46-c were clustered with peach and plum, respectively. The spatio-temporal expression pattern of MYB46 transcription factor gene was studied by qRT-PCR technology. It was found that two almond cultivars were expressed at different developmental stages. The correlation analysis showed that endocarp thickness of two almond varieties was significantly correlated with the lignin content. It was speculated that MYB46 transcriptional factor gene participated in the regulation of the metabolism of lignin in the endocarp of almond.