中文摘要：

前期通过转录组结合表达谱分析发现一类MBD片段在低温解除牡丹花芽内休眠中的差异表达,为了进一步研究MBD基因特征及其在牡丹休眠解除中的作用,利用RACE扩增获得1204bpPsMBD5全长cDNA,其中编码框1056bp,推测编码351个氨基酸。生物信息学分析结果显示,PsMBD5蛋白分子量约为38.1274kDa,等电点为5.14,不稳定系数为44.27,推测该蛋白为不稳定蛋白。同源性分析表明,牡丹PsMBD5与梅PmMBD5的同源性最高,为38.1%,与亚麻荠CsMBD5的同源性最低,为25.8%,与13种拟南芥MBD蛋白同源性最高的是AtMBD5。实时荧光定量PCR分析表明,PsMBD5基因在牡丹不同组织中均有表达,在初花期牡丹的根中转录水平最高,在花瓣、心皮和萼片中次之,在雄蕊中最低;PsMBD5基因在牡丹花芽中受低温诱导,且转录水平在低温处理14d时达到最大值,之后维持较高的转录水平。研究结果为进一步解析PsMBD5基因对牡丹花芽的休眠解除的调控机制奠定基础。

英文摘要：

The previous results of the transcriptome and expression profiling analysis in tree peony found that a MBD-like fragment was differentially expressed during low temperature induced dormancy release.To investigate the characteristic and putative function of MBD during tree peony bud dormancy release,total 1 204 bp full length cDNA of PsMBD5 was obtained by RACE amplification.The coding fame of 1 056 bp encoded 351 amino acids.The result of bioinformatics analysis showed that the molecular weight of PsMBD5 was 38.127 4 kDa,isoelectric point was 5.14,which indicated that PsMBD5 was an unstable hydrophilic.The result of homology analysis indicated that the similarity between the PsMBD5 and PmMBD5 was the highest with 38.1% identity,and CsMBD5 was the lowest with 25.8%.When compared with 13 kinds of AtMBD,the identity between the PsMBD5 and AtMBD5 was the highest.The expression patterns were analyzed by Real-time quantitative PCR,and the results showed that the transcript level of PsMBD5 at the early stage of flowering in root was the highest,followed by in petals,carpel and sepals,and in stamen was the lowest.During the whole process of chilling fulfillment,PsMBD5 was highly induced by low temperature.The transcript level of PsMBD5 was the highest after 14 d chilling fulfillment,and maintained a high level of transcription after that.These results would provide theoretical basis to validate the regulation mechanism of PsMBD5 during the peony bud dormancy release.