Abstract: HD-zip transcription factor is a unique transcription factor in higher plants,which plays an important role in plants’ growth and development and their responses to biotic and abiotic stresses. In this experiment,the full-length sequence of HD-zip transcription factor TrATHB-12 of white clover cultivar ‘Ladino’ was obtained through homology acquisition and RACE. Relevant software was used to analyze its bioinformatics characteristics,and fluorescence quantitative method was used to study its response to abiotic stresses,signals and hormones. The results showed that TrATHB-12 has a full length of 1 175 bp,an open reading frame (ORF) containing 744 nucleotide sequences,248 amino acids,two conserved domains HD and LZ,so it belongs to HD-zip I transcription factors. Homologous analysis and evolutionary tree results showed that the nucleotide and protein sequences of TrATHB-12 gene in white clover are of high similarity with other legumes. It’s a conservative gene. Bioinformatics analysis showed that TrATHB-12 encoded protein has a theoretical molecular weight of 28 738,an isoelectric point of 5.18,no signal peptide or transmembrane structure,which is an unstable hydrophilic protein. The results of expression model showed that the expression TrATHB-12 in roots and leaves was different at various treatment and treatment time. Among them,drought can significantly induce the expression of TrATHB-12 gene in leaves,and salt can significantly induce the expression of TrATHB-12 in roots. TrATHB-12 has different responses to other stresses. The expression of TrATHB-12 was significantly increased under ABA and IAA treatment,and there was no obviously response to Spm. TrATHB-12 has significant response to H₂O₂ and NO signals. This study laid a foundation for further research and application of TrATHB-12 gene to improving stress resistance in white clover.

Key words: White clover, HD-Zip, Gene clone, Bioinformations, Expression pattern

摘要： HD-Zip转录因子是高等植物中特有的一类转录因子，在高等植物的生长发育以及生物和非生物胁迫等逆境应答中起着重要的调控作用。本试验以白三叶品种‘拉丁诺’（Trifolium repens ‘Ladino’）为试验材料，通过同源获取和cDNA末端快速扩增技术（Rapid amplification of cDNA ends，RACE）得到白三叶HD-Zip类转录因子TrATHB-12全长序列，并利用相关软件分析其生物信息学特性，使用荧光定量的方法研究其对非生物胁迫、信号分子和激素的响应，从而为后续构建载体转染白三叶以研究其在各种胁迫下的响应提供一定的基础。试验结果表明，TrATHB-12全长cDNA为1 175 bp，开放阅读框（Open Reading Frame，ORF）包括744个核苷酸序列，编码248个氨基酸，有2个保守结构域，仅包含HD和LZ，属于HD-Zip I类转录因子。同源分析和进化树结果显示，TrATHB-12基因核苷酸和蛋白质序列与其他豆科植物相似度较高，是较为保守的基因。生物信息学分析发现TrATHB-12编码的蛋白理论分子量为28 738，等电点为5.18，无信号肽和跨膜结构，是不稳定亲水蛋白。表达模式结果显示，TrATHB-12基因在根系和叶片中的表达量有所差异。其中，干旱可以显著诱导叶片中TrATHB-12基因的表达，盐胁迫则可以显著诱导根系中TrATHB-12基因的表达，TrATHB-12对其他逆境均有不同程度的响应；脱落酸（Abscisic acid，ABA）和吲哚乙酸（Indole acetic acid，IAA）处理下叶片中TrATHB-12的表达量显著上升；TrATHB-12对于H₂O₂和NO信号分子有较明显的响应。综上，本试验可为继续深入研究TrATHB-12基因，从而提高白三叶抗逆性奠定一定的基础。

关键词: 白三叶, HD-Zip, 基因克隆, 生物信息学, 表达模式