三色堇热激转录因子基因VtHSFB2b的克隆及表达分析

Cloning of HSFB2b Gene from Pansy and Analysis on Its Expression to Heat Stress

热激转录因子(heat stress transcription facfor,HSF)在植物响应热胁迫中起关键调控作用。为研究在高温胁迫下三色堇的分子机理,提高其对高温的抗性,本研究以三色堇耐热材料DFM-16和热敏材料08H为试验材料,基于转录组测序,克隆了热激转录因子VtHSFB2b基因全长cDNA序列,并采用实时荧光定量PCR检测了该基因在热胁迫下的表达模式。结果表明,两个材料中VtHSFB2b基因的开放阅读框长度相同,均为975 bp,编码324个氨基酸,氨基酸序列相似性为98.15%。序列比对和系统进化树分析,VtHSFB2b蛋白序列与其他植物的HSFB2b进化距离最近,推测该基因属于HSFB2亚族。预测三色堇HSFB2b蛋白的三级结构主要由3个α-螺旋和4个β-折叠组成。实时荧光定量结果表明,42℃热激处理后两种材料中VtHSFB2b基因表达模式相似,在1 h时均达到表达顶峰,耐热材料DFM-16的表达量是热敏材料08H的11.3倍,这说明VtHSFB2b能够响应高温胁迫,且其表达量与三色堇的耐热性呈正相关。本研究为进一步探索三色堇在高温胁迫下的HSFB2b调控机制提供了科学依据。

Heat stress transcription factor(HSF)plays a key regulatory role in plant response to heat stress.In order to study the molecular mechanism of Viola tricolor under high temperature stress and improve its resistance to high temperature,Pansy heat-resistant material DFM-16 and heat sensitive material 08 H were used as experimental materials in this study.Based on the transcriptome sequencing,the gene of heat shock transcription factor VtHSFB2 b was cloned.The expression pattern of the gene under heat stress was detected by real-time quantitative PCR.The results showed that the open reading frames of VtHSFB2 b gene were the same in both materials,all of which were 975 bp,encoding 324 amino acids,and the amino acid sequence similarity was 98.15%.Phylogenetic tree analysis showed that the amino acid sequence of VtHSFB2 b gene was the closest to that of HSFB2,suggesting that it belonged to the HSFB2 subfamily.The high-level structure of VtHSFB2 b protein is mainly composed of 3 alpha helices and 4 beta sheets.The real-time fluorescence quantitative results showed that the expression pattern of VtHSFB2 b gene was similar in the two materials after heat shock treatment at 42℃,and reached the peak of expression at 1 h.The expression level of heat-resistant material DFM-16 was 11.3 times that of heat-sensitive material 08 H.Pansy VtHSFB2 b is able to respond to high temperature stress,and its expression is positively correlated with the heat resistance of Pansy.This study provides a scientific basis for further exploring the regulatory mechanism of HSFB2 b in pansy under high temperature stress.