辣椒NRT基因家族的系统鉴定、进化与表达分析

Identification,evolution and expression analysis of the NRT gene family in Capsicum annuum

[目的]本研究旨在鉴定辣椒硝酸盐转运蛋白(NRT)基因家族成员,分析其基本性质、染色体定位、进化关系以及在不同组织、不同果实发育阶段和不同非生物胁迫下的表达特征。[方法]利用生物信息学方法在辣椒‘遵辣1号’基因组中鉴定NRT基因家族并分析其理化性质、基因结构、染色体定位、共线性、顺式作用元件分布和进化关系等;利用转录组数据分析辣椒NRT(CaNRT)基因在不同组织和不同果实发育阶段中的表达特征,并利用RT-qPCR技术分析在不同非生物胁迫下的表达模式。[结果]辣椒中共包含73个CaNRT基因,不均匀分布在10条染色体上。系统进化分析表明,CaNRT基因可分为3个亚家族,同一亚家族具有相似基因结构和保守基序。顺式作用元件分析结果表明CaNRT可能受光、激素、逆境胁迫等多种因素调控。CaNRT1亚家族成员主要在根、茎、叶中表达量较高,CaNRT2亚家族在任何时期表达量都较低,CaNRT3亚家族存在组织表达差异性,主要在根中高表达。逆境胁迫数据表明,CaNRT1.18、CaNRT3.3、CaNRT3.1、CaNRT2.1、CaNRT1.23在低温、高温、干旱、盐和氧化处理下明显响应,所有CaNRT基因在低温处理时均有不同程度的正向响应。[结论]在辣椒基因组中共鉴定获得73个CaNRT基因,筛选出多个在辣椒生长发育和逆境胁迫中具有重要作用的关键基因。

[Objectives]The study aimed to identify the members of the nitrate transporter protein(NRT)gene family in Capsicum annuum,and analyze their basic properties,chromosomal location,evolutionary relationships,and expression characteristics across different tissues,developmental stages of fruits,and under various abiotic stresses.[Methods]The NRT gene family was analyzed with the bioinformatics methods in genome of‘Zunla 1’pepper,and the physical and chemical properties of protein,the gene structure,chromosome localization,collinearity analysis,cis-acting elements and evolutionary relationship were determined.Transcriptome data were utilized to examine the expression characteristics of NRT genes in various tissues and fruits during varying developmental stages.The expression profiles were also analyzed under variant abiotic stresses using RT-qPCR.[Results]A total of 73 CaNRT genes were identified in C.annuum and unevenly distributed on 10 chromosomes.The phylogenetic analysis revealed that these genes could be grouped into three subfamilies,with a similar gene structure and conserved motifs.The cis-acting element analysis results suggested that CaNRT genes might be regulated by various factors,including light,hormones and adversity stress.Members of the CaNRT1 subfamily exhibited high expression predominantly in roots,stems,and leaves.The CaNRT2 subfamily displayed low expression at all times,while the CaNRT3 subfamily showed differential tissue expression and was primarily highly expressed in roots.The abiotic stress data showed that CaNRT1.18,CaNRT3.3,CaNRT3.1,CaNRT2.1 and CaNRT1.23 responded more strongly to low temperature,high temperature,drought,salt and oxidative treatments.All CaNRT genes exhibited a positive reaction to varying degrees under low-temperature treatment.[Conclusions]73 CaNRT genes were identified in the pepper genome,and several key genes were screened which were involved in the regulation of growth and development and response to multiple abiotic stresses.