Abstract: MYB (MYB transcription factor) is a class of transcription factors that plays an important role in plant growth and stress resistance,including salt stress,drought stress,heavy metal stress,and plant disease resistance,its gene family is one of the largest transcription factor families in plants. Based on the transcriptome data of Poa pratensis ‘Baron’,we obtained a 705 bp CDS sequence and a 1115 bp promoter sequence of PpMYB2 by using homologous cloning and chromosome walking techniques. The qRT-PCR results showed that PpMYB2 had the highest expression level in the roots,followed by the leaves and the lowest expression level in the,it also respond to plant hormones such as GA and ABA treatment,and showed a significantly upregulated expression trend under drought stress (15% PEG6000) and salt stress treatments (150 mmol·L^-1 NaCl). The subcellular localization results indicated that PpMYB2 was located in the nucleus. Promoter analysis showed that the promoter region of PpMYB2 contains plant hormone responsive elements such as auxin and gibberellin,as well as stress responsive elements such as low temperature and drought. These results suggested that PpMYB2 played an important role in plant response to stresses,and further research on it had a guiding significance for exploring its stress resistance mechanism in Poa pratensis.

Key words: MYB gene, Transcription factor, Gene cloning, Expression pattern, Subcellular localization

摘要： MYB(MYB transcription factors)是一类在植物生长发育及抗逆方面起重要作用的转录因子，其功能包含抗盐胁迫、抗干旱胁迫、抗重金属胁迫及抗病害胁迫等，它的基因家族属于植物最大的转录因子家族之一。本研究基于草地早熟禾‘巴润’(Poa pratensis ‘Baron’)前期转录组数据，利用同源克隆及染色体步移技术，获得了PpMYB2的705 bp的编码序列(Coding sequence，CDS)及1115 bp的启动子序列。qRT-PCR结果显示，PpMYB2在根中具有最高的表达量，其次是叶片在叶鞘中的表达量最低，同时，PpMYB2的表达可以响应植物激素GA及ABA，并在干旱胁迫(15% PEG6000)及高盐胁迫(150 mmol·L^-1 NaCl)下，呈现出表达量显著上调的变化趋势。亚细胞定位结果表明，该基因定位于细胞核中。启动子分析表明，该基因启动子区域含有生长素、赤霉素等植物激素响应元件及低温、干旱等逆境响应元件。由此表明，PpMYB2在植物响应胁迫中起到重要作用，对其的进一步研究对探索草地早熟禾抗逆机理具有指导意义。

关键词: MYB基因, 转录因子, 基因克隆, 表达模式, 亚细胞定位