马铃薯StMYB44基因对蔗糖的响应

Response of StMYB44 Gene to Sucrose in Potato

MYB转录因子存在于所有真核生物中,是最具代表的转录因子家族之一,广泛参与植物发育、苯丙烷代谢、生物与非生物胁迫响应、激素响应以及细胞形态建成等过程。该研究从马铃薯品种‘青薯9号’中克隆得到StMYB44基因(GenBank登录号XM_006367359.2),该基因CDS长为963 bp,编码320个氨基酸,含有2个SANT结构域。实时荧光定量PCR结果显示,StMYB44基因在花中表达最高,在匍匐茎中表达最低;且StMYB44基因在无蔗糖处理下表达上调,在高浓度蔗糖处理下(6%、9%)表达下调。构建表达载体并进行遗传转化烟草发现,StMYB44基因突变体在无蔗糖条件下的长势明显好于野生型,而在高蔗糖浓度下(6%、9%)的长势弱于野生型,且蔗糖浓度越高,差异越大。研究表明,蔗糖浓度能够调节StMYB44基因的表达,推测StMYB44基因可能在植物响应蔗糖中起重要作用。

MYB transcription factor is one of the most representative transcription factor families in all eukaryotes.It is widely involved in plant development,phenylpropanoid metabolism,biotic and abiotic stress response,hormone response,and cell morphogenesis.In this study,StMYB44 gene(GenBank accession number is XM_006367359.2)was cloned from potato‘Qingshu 9’,whose sequence length was 963 bp,encoded 320 amino acids that contained two SANT domains.The result of quantitative real-time PCR showed that StMYB44 had the highest expression in flowers and the lowest expression in stolon;StMYB44 was up-regulated under sucrose-free treatment and down-regulated under high-concentration sucrose treatment(6%,9%).Construction of expression vector and genetic transformation of tobacco found that the growth of StMYB44 mutant under sucrose-free conditions was significantly better than that of wild-type,while at high sucrose concentration(6%,9%),the growth of StMYB44 mutant was weaker than wild-type,and the higher the sucrose concentration,the difference is greater.These results indicates that sucrose concentration can regulate the expression of StMYB44,suggesting that this gene may play an important role in plant response to sucrose.