【摘要】 DIR(Dirigent)基因家族在植物生长发育与逆境响应中具有重要功能，但其在玉米中的系统性鉴定尚未有相关研究。本研究通过全基因组分析，在玉米B73-V4参考基因组中鉴定到39个DIR基因家族成员，并系统解析其理化性质、结构特征及保守基序。结果表明：77.0%(30个)的ZmDIR蛋白具有高稳定性，64.1%(25个)的ZmDIR蛋白具有疏水性。亚细胞定位预测显示：11个ZmDIR蛋白定位于叶绿体中，10个定位于内质网中，8个定位于细胞质中，只有5个定位于液泡中，说明玉米的DIR蛋白存在多样化的生物学功能。进化分析表明：ZmDIR基因可分为3个亚家族，其启动子区域包含多样化的逆境响应元件及系统发育相关响应元件。围绕ZmDIR17基因进行功能解析，发现其突变导致玉米籽粒形态发生显著改变，且玉米籽粒蛋白质含量显著增加，淀粉和总木脂素含量明显降低。蛋白互作网络与GO富集分析表明，ZmDIR17蛋白通过参与核糖体生物发生（互作Pescadillo同源蛋白）和苯丙烷代谢（调控木脂素合成）双重通路协调碳氮分配。本研究揭示了玉米DIR基因家族的系统特征，并初步探索了ZmDIR17基因及其编码蛋白通过整合初级与次生代谢调控籽粒发育的分子机制，可为玉米品质改良提供新的参考。更多还原

【Abstract】 The DIR(Dirigent)gene family plays an important role in plant growth,development,and stress response,but its systematic identification in maize has not been studied. In this study,39 DIR gene family members were identified in the maize B73-V4 reference genome through genome-wide analysis,and their physicochemical properties,structural characteristics,and conserved motifs were systematically investigated. The results showed that 77. 0%(30) of ZmDIR proteins had high stability,and 64. 1%(25) had hydrophobicity.Subcellular localization prediction showed that 11 ZmDIR proteins were localized in chloroplast,10 in endoplasmic reticulum,8 in cytoplasm,and only 5 in vacuole,indicating the diverse biological functions of maize DIR proteins. Evolutionary analysis classified ZmDIR genes into 3 subfamilies,and their promoter regions contained diverse stress-responsive elements and phylogenetically related regulatory elements. Functional analysis was conducted around the ZmDIR17 gene,and it was found that its mutation resulted in significant changes in grain morphology,with a significant increase in protein content of maize grain,and a significant decrease in starch content and total lignin content. Protein interaction network and GO enrichment analysis indicated that ZmDIR17 protein coordinated carbon and nitrogen allocation by participating in dual pathways of ribosome biogenesis(interacting with Pescadillo homologous proteins)and phenylpropanoid metabolism(regulating lignin synthesis). This study reveals the systematic characteristics of the maize DIR gene family and explores the molecular mechanism by which the ZmDIR17 gene and its encoded protein regulate grain development by integrating primary and secondary metabolism,providing new references for maize quality improvement.更多还原