Table_3_Structural, Functional, and Evolutionary Characterization of Major Drought Transcription Factors Families in Maize.XLSX

Drought is one of the major threats to the maize yield especially in subtropical production systems. Understanding the genes and regulatory mechanisms of drought tolerance is important to sustain the yield. Transcription factors (TFs) play a major role in gene regulation under drought stress. In the present study, a set of 15 major TF families comprising 1,436 genes was structurally and functionally characterized. The functional annotation indicated that the genes were involved in ABA signaling, ROS scavenging, photosynthesis, stomatal regulation, and sucrose metabolism. Duplication was identified as the primary force in divergence and expansion of TF families. Phylogenetic relationship was developed for individual TF and combined TF families. Phylogenetic analysis clustered the genes into specific and mixed groups. Gene structure analysis revealed that more number of genes were intron-rich as compared to intron-less. Drought-responsive cis-regulatory elements such as ABREA, ABREB, DRE1, and DRECRTCOREAT have been identified. Expression and interaction analyses identified leaf-specific bZIP TF, GRMZM2G140355, as a potential contributor toward drought tolerance in maize. Protein-protein interaction network of 269 drought-responsive genes belonging to different TFs has been provided. The information generated on structural and functional characteristics, expression, and interaction of the drought-related TF families will be useful to decipher the drought tolerance mechanisms and to breed drought-tolerant genotypes in maize.

干旱是威胁玉米产量的主要胁迫因素之一，尤其在亚热带种植系统中影响显著。解析玉米耐旱相关基因及其调控机制，对维持玉米产量稳定具有重要意义。转录因子（Transcription factors, TFs）在干旱胁迫下的基因调控过程中发挥核心作用。本研究针对涵盖1436个基因的15个主要TF家族开展了结构与功能特征鉴定。功能注释结果显示，这些基因参与脱落酸（Abscisic acid, ABA）信号通路、活性氧（Reactive oxygen species, ROS）清除、光合作用、气孔调控以及蔗糖代谢等生物学过程。研究表明基因复制是TF家族分化与扩张的主要驱动力。本研究分别构建了单个TF家族及全部TF家族的系统发育关系，系统发育分析将这些基因划分为特异类群与混合类群。基因结构分析显示，含内含子较多的基因数量显著多于无内含子基因。本研究还鉴定到ABREA、ABREB、DRE1、DRECRTCOREAT等干旱响应顺式调控元件。通过表达与互作分析，筛选得到叶片特异性表达的碱性亮氨酸拉链转录因子（basic leucine zipper transcription factor, bZIP TF）GRMZM2G140355，其可作为玉米耐旱性的潜在调控因子。本研究同时提供了隶属于不同TF家族的269个干旱响应基因的蛋白质互作网络。本研究获得的干旱相关TF家族的结构与功能特征、表达模式及互作关系数据，将为解析玉米耐旱机制以及培育耐旱玉米种质提供重要理论支撑与参考依据。