玉米NRL基因家族鉴定与逆境表达分析

Genome-wide Identification and Expression Response to Stresses Analysis of NRL Gene Family in Zea mays

NRL(NPH3/RPT2-Like)是植物所特有的一类光响应蛋白,在向光素信号途径中发挥重要作用。利用生物信息学手段结合qRT-PCR技术,在玉米基因组水平对该家族基因进行鉴定并对其编码蛋白的性质、结构、进化、生育期组织表达和逆境表达进行分析。结果鉴定了31个ZmNRL基因,不均匀地分布于玉米9条染色体上,编码的氨基酸序列长度在464~749个,预测具有叶绿体、细胞核和细胞质等亚细胞定位。依据蛋白保守性将ZmNRL家族划分为四大类,基因结构也具有一定的保守性,多数基因含有4个外显子。基因启动子存在大量脱落酸、茉莉酸、光响应和抗氧化等顺式元件分析,其中G-box和Sp1等两类光相关元件数量较多。ZmNRL家族基因在生育期组织部位表达具有一定的时空特异性,总体表达量不高,仅有ZmNRL2、ZmNRL4、ZmNRL24和ZmNRL29相对高表达。通过生育期组织表达数据共表达及其模块GO富集分析发现,6个ZmNRL基因可通过叶绿体等生物发生及组装生物过程,参与对叶片生长发育的调控。qRT-PCR结果表明,高温处理玉米幼苗ZmNRL12上调表达显著,干旱、盐和病原物接种处理ZmNRL5、ZmNRL7和ZmNRL19基因下调表达。综上,在玉米基因组鉴定出31个ZmNRL基因,该家族基因不仅具有明显的组织表达特异性,而且可参与玉米幼苗对生物和非生物逆境应答。

NRL(NPH3/RPT2-Like)is a type of light-responsive protein unique to plants and plays a vital role in the phototropic signal pathway.To reveal the NRL gene maize genome′s characteristics and expression,we analyzed them using bioinformatics methods combined with qRT-PCR technology.The property,structure,evolution of their encoded proteins,and growth period tissue expression and stress expression were analyzed.31 ZmNRL genes identified were located in nine maize chromosomes,encoding protein amino acids 464-749 aa,which predicted to have chloroplast,nuclear and cytoplasmic locations.According to protein conservation,ZmNRL family was divided into four categories.Their gene structure also presented certain conservation,the most contained four exons.Analysis of the cis-elements of gene promoters revealed a large number of abscisic acids,jasmonic acid,light response,and anti-oxidation elements,among which G-box and Sp1 were two types of light-related elements.The expression of ZmNRL family genes in tissues during the growth period showed a temporal and spatial specificity,and the majority expression level was not high.Only ZmNRL2,ZmNRL4,ZmNRL24,and ZmNRL29 highly expressed.Furthermore,the characteristic modules were produced based on the data of the tissue co-expression genes.And the GO enrichment analysis of a particular leaf growth module containing six ZmNRL genes,mainly associated with the plastid organization biological processes and rRNA binding molecular functions.The expression of ZmNRL5,ZmNRL7,ZmNRL12,and ZmNRL19 genes were analyzed by qRT-PCR under salt,drought,high temperature,and Rhizoctonia solani inoculation treatments.The results showed that ZmNRL12 was significantly up-regulated in maize seedlings treated with high temperature,while ZmNRL5,ZmNRL7 and ZmNRL19 genes were down-regulated in drought,salt and pathogen treatments.In summary,31 ZmNRL genes were identified in the maize genome.They not only had apparent specific tissue expression but also participated in biotic and abiotic stress responses.