摘要：

分子伴侣热激蛋白HSP40是通过 J 结构域与 HSP70 结合,从而帮助蛋白质折叠,参与了植物多种胁迫反应。然而,NtHSP40基因家族响应UV-B辐射的机制与功能尚不明确。通过生物信息学方法在全基因组水平鉴定了NtHSP40基因家族成员,并开展系统进化分析、共线性分析、启动子顺式作用元件分析、染色体定位、基因结构及理化性质分析,明确了NtHSP40基因家族的基本特征。在UV-B辐射处理的烟草幼苗中,基于转录组数据筛选出8个差异调控基因,通过实时荧光定量PCR(qRT-PCR)验证了候选基因的表达水平,并采用分光光度法测定了代谢产物总多酚含量。结果表明,烟草K326基因组中共有48个NtHSP40基因,分布于20条染色体上,均编码含有J结构域的蛋白,可进一步划分为3个亚家族;可变的基因结构与蛋白序列特征提示NtHSP40基因家族成员功能存在分化,其中8个NtHSP40基因对UV-B辐射产生响应,且与烟草总多酚含量变化相关。该研究成果为进一步阐明NtHSP40基因家族在植物胁迫响应及烟草次生代谢中的功能,以及提升烟叶品质奠定了基础。

关键词: 烟草, 热休克蛋白40家族, 生物信息学, 紫外线辐射, 多酚含量

Abstract:

The molecular chaperone heat shock protein HSP40 binds to HSP70 through the J domain to assist in protein folding and participates in various stress responses in plants.However,the mechanism and function of NtHSP40 gene family in response to UV-B radiation remain unknown.Through bioinformatics methods,the members of the NtHSP40 gene family were identified at the whole-genome level,and phylogenetic analysis,collinearity analysis,cis-acting elements of the promoter,chromosomal localization,gene structure analysis and physical and chemical property analysis were carried out to clarify the basic characteristics of the NtHSP40 gene family.In tobacco seedlings treated with UV-B radiation,RNA-sequencing analysis was performed to investigate the eight differentially regulated genes according to the transcriptome data.The expression levels of candidate genes belonging to NtHSP40 gene family were investigated by Quantitative Real-time PCR(qRT-PCR)experiments and the total polyphenol content of metabolites was quantified by spectrometry.The results showed that there were 48 NtHSP40 genes in the genome of tobacco K326.These genes were distributed on 20 chromosomes and all encoded J domain proteins which can be further divided into three subfamilies.The variable gene structure and protein sequence characteristics indicated the diversification of the functions of the NtHSP40 gene family members.Among them,eight NtHSP40 genes responded to UV-B radiation,and was correlated with the total polyphenol content in tobacco.The research findings establish a foundation for further elucidating the functions of the NtHSP40 gene family in plant stress responses and secondary metabolism in tobacco,and for enhancing the quality of tobacco leaves.

Key words: Nicotiana tabacum, Heat shock proteins HSP40 family, Bioinformatics, Ultraviolet-B, Polyphenol content

中图分类号: 

• S572

• Q943.2植物基因工程