茶树HD-Zip转录因子基因的克隆及其对非生物胁迫的响应分析

Cloning and expression analysis of the gene encoding HD-Zip under abiotic stress in Camellia sinensis

茶树作为一种叶用植物,具有重要的经济价值。非生物胁迫对茶树的生长发育过程和茶叶的生产影响很大。本研究采用RT-PCR方法从茶树‘龙井43’cDNA中克隆获得1个编码HD-Zip转录因子的基因CsHB1。序列分析显示,CsHB1基因cDNA长为1 380 bp,编码459个氨基酸,含有典型的START结构域。进化分析显示,茶树CsHB1属于HD-Zip家族转录因子的IV亚族。多序列对比发现,CsHB1与其他物种的HD-Zip类蛋白的氨基酸序列具有78.05%的相似性,如葡萄、烟草、芝麻等。对CsHB1转录因子理化性质、亲/疏水性、无序化分析显示,CsHB1转录因子是疏水性蛋白且显偏碱性,不存在无序化区域。空间结构分析显示,CsHB1有3个α-螺旋,多个β-折叠,且有START结构域。利用荧光定量PCR方法分析了CsHB1在高温(38°C)、低温(4°C)、PEG干旱(200 g·L^(-1))、NaCl(200 mmol·L^(-1))处理1、4、8、12 h的表达情况。结果表明,CsHB1基因在不同非生物胁迫处理下均能诱导表达,且表达差异性明显。

Tea tree [Camellia sinensis（L.） O. Kuntze] as a kind of leaf plants, has important economic value. However, abiotic stress has a great influence on the production of tea. In this study, a gene encoding HD-Zip transcription factor（CsHB1） was cloned from tea cultivar ‘Longjing 43＇ cDNA by RT-PCR method. Sequence analysis showed that the conserved region of CsHB1 contained 1 380 bp encoding a total of 459 amino acids, containing a typical START domain. Evolutionary analysis showed that the tea plant CsHB1 belonged to the HD-Zip IV family. Multiple sequence comparison revealed that CsHB1 had 78.05% similarity to the amino acid sequence of the HD-Zip protein of other species, such as Vitis vinifera, Nicotiana attenuata, Sesamum indicum, and so on. The analysis of the physical and chemical properties of CsHB1 transcription factors, pro/hydrophobicity, and disorder showed that CsHB1 transcription factor was a hydrophobic protein and showed partial alkalinity, and there was no disorder region. According to the analysis of spatial structure that CsHB1 has 3 alpha-helices, multiple beta-folds, and START domain. The expression of CsHB1 at high temperature（38°C）, low temperature（4°C）, PEG drought（200 g·L^（-1）） and NaCl（200 mmol·L^（-1）） was analyzed by fluorescence quantitative PCR. The results showed that CsHB1 could induce the expression under stress, and the difference was obvious.