玉米ZmNRT关键基因挖掘以及氮响应基因共表达网络构建

以玉米自交系B73（V4版本）作为参考基因组，利用生物信息学方法鉴定玉米ZmNRT基因家族成员，从系统发育关系、GO（Gene Ontology）富集、基因结构和玉米不同时期及组织下的表达谱等方面全面解析玉米ZmNRT基因家族。基于qPCR实验和共表达网络分析，对玉米ZmNRT家族基因在氮响应中的作用进行系统的研究。结果表明，在玉米全基因组水平上共鉴定到 162 个 ZmNRT 基因，主要分为 ZmNRT1（62 个）和 ZmNRT2（100 个） 两大类群。GO富集发现，仅46个基因参与硝态氮转运过程，这些基因被不均等分成7个亚家族，每个家族1～15个基因。基因表达模式分析结果显示，不同生育期和组织下ZmNRT基因表达是差异的。在氮诱导下，qPCR鉴定结果显示，12个ZmNRT基因是氮响应基因，9个基因表达上调，3个基因表达下调。共表达网络结果发现，其中10个ZmNRT基因与已知的氮代谢基因存在显著共表达关系（|r|>0.8 p-value<0.05），推测这10个基因可能是调控玉米氮代谢的关键基因。

ZmNRT Key Genes Mining and Nitrogen Responsive Genes Co-expression Network Construction in Maize

In this study, maize inbred line B73(V4) was used as the reference genome to identify the members of maize ZmNRT gene family by using bioinformatic methods, from the aspects of phylogenetic relationship, GO (Gene Ontology) enrichment, gene structure and expression profiles. Under nitrogen induction, the role of ZmNRT family genes in nitrogen response in maize was systematically studied based on qPCR assay and co-expression network analysis. The results showed that a total of 162 ZmNRT genes were identified at the genome-wide level of maize, which were mainly divided into two groups, 62 ZmNRT1 genes and 100 ZmNRT2 genes. Then GO enrichment found that only 46 genes were involved in nitrate transport process, and these genes were unequally divided into 7 subfamilies with 1-15 genes, respectively. The result of gene expression pattern analysis indicated that ZmNRT gene expression differed in different growth stages and tissues. Under nitrogen induction, the qPCR results showed that 12 genes were nitrogen-responsive genes, of which 9 genes were up-regulated while 3 genes were down-regulated. Subsequently, through the co- expression network constructed, we found that 10 of the nitrogen responsive genes had significant co-expression relationships with annotated key genes of nitrogen metabolism(|r|>0.8, p-value<0.05), and speculated that these 10 genes might be the key genes of regulating nitrogen metabolism in maize.