蓝莓花芽休眠相关MADS-box基因VcDAM1的克隆与表达分析

Cloning and expression analysis of dormancy-associated MADS-box gene Vc DAM1 from blueberry(Vaccinium corymbosum)

休眠相关MADS-box(DAM)基因在植物芽休眠及解除过程中发挥重要作用。本研究以‘蓝丰’蓝莓(Vaccinium corymbosum)休眠花芽为材料,利用RT-PCR及RACE技术,克隆获得Vc DAM1基因(Gen Bank登录号为KF871069)。该基因全长1376 bp,包含一个750 bp的开放阅读框,编码249个氨基酸。序列比对发现,该基因编码的蛋白质具有典型的MIKC^C型MADS-box结构域和K-box结构域,其氨基酸序列与砂梨DAM同源性较高。实时定量PCR结果表明,该基因在蓝莓花芽中表达量最高,且随花芽休眠进程呈现规律变化,在内休眠期间表达量持续上升,内休眠解除后表达量迅速下降;外源脱落酸能使该基因表达上调,外源赤霉素和单氰胺使该基因表达下调。推测该基因调控蓝莓花芽的休眠。

Dormancy-associated MADS-box（DAM） genes play important roles in regulating bud dormancy induction and release in plants. In this study, a MADS-box gene, named as VcDAM1（Gen Bank accession number KF871069） was isolated from the dormant floral buds of blueberry（Vaccinium corymbosum） using RT-PCR and rapid amplification of c DNA ends（RACE） techniques. The gene consists of 1376 bp which has a 750-bp open reading frame（ORF） coding a protein of 249 amino acids. Multiple sequence comparison revealed that VcDAM1 encodes a protein, which is the typical MIKC^C-type MADS-box protein with the MADS-box domain and K-box region. Phylogenetic analysis indicated that the amino acid sequence of VcDAM1 had high homology with dormancy-associated MADS-box from Pyrus pyrifolia. qRT-PCR analysis indicated that the gene expression level in flower buds was the highest among all the organs, and with the process of flower bud dormancy, the gene expression level changed regularly. The gene expression level was increased during dormancy, and decreased rapidly after the dormancy was released. Exogenous abscisic acid（ABA） up-regulated the expression of VcDAM1, while exogenous gibberellin（GA） and hydrogen cyanamide（HC） down-regulated the expression of VcDAM1. The results imply that VcDAM1 gene might play an important role in regulating bud dormancy in blueberry.