National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou, 450002, China.
Plant Physiol Biochem. 2020 Nov;156:420-435. doi: 10.1016/j.plaphy.2020.09.027. Epub 2020 Sep 25.
The APETALA2/ethylene response factor (AP2/ERF) transcription factor (TF) superfamily play crucial roles in plant growth and development as well as biotic and abiotic stresses response. Here, we systematically characterized 375 AP2/ERF TFs in the Nicotiana tabacum genome. Phylogenetic tree topology and conserved domain number allowed TF classifications into three families of 29 AP2, 341 ERF, and 5 RAV genes, which were unevenly distributed throughout 24 tobacco chromosomes. Gene family expansions were retained from whole genome or segmental duplications followed by tandem duplication. Gene structure and motif analysis revealed intra-group conservation. MicroRNA target site prediction identified nine miR172 family members targeting six NtAP2-family genes; 41 NtAP2/ERFs participated in protein co-regulatory networks. NtAP2/ERF gene global expression profiles ascertained by RNA-seq displayed diverse expression patterns across tissues and under different abiotic and biotic stresses (including drought, cold, and Phytopthora parasitica inoculation). As determined by qRT-PCR, the expression of NtAP2/ERF were induced by five hormone and four abiotic stress. RNA interference of NtRAV-4 in tobacco accelerates seed germination, enhance root development and leaf photosynthetic ability. Suppression of NtRAV-4 increases drought tolerance by improving antioxidant defense ability and reduced relative electrolyte leakage under drought stress. These results enhance understanding of NtAP2/ERF gene function and will facilitate genetic improvement of tobacco stress tolerance.
AP2/乙烯响应因子 (AP2/ERF) 转录因子 (TF) 超家族在植物生长发育以及生物和非生物胁迫响应中发挥着关键作用。在这里，我们系统地鉴定了烟草基因组中的 375 个 AP2/ERF TF。系统发育树拓扑结构和保守结构域数量允许将 TF 分为 29 个 AP2、341 个 ERF 和 5 个 RAV 基因三个家族，这些基因在 24 条烟草染色体上不均匀分布。全基因组或片段重复后通过串联重复保留了基因家族的扩张。基因结构和基序分析揭示了组内保守性。miRNA 靶位点预测确定了 9 个靶向 6 个 NtAP2 家族基因的 miR172 家族成员；41 个 NtAP2/ERF 参与了蛋白质共调控网络。通过 RNA-seq 确定的 NtAP2/ERF 基因全局表达谱显示了不同组织和不同非生物和生物胁迫（包括干旱、寒冷和寄生疫霉接种）下的多样化表达模式。通过 qRT-PCR 确定，五种激素和四种非生物胁迫诱导了 NtAP2/ERF 的表达。烟草中 NtRAV-4 的 RNA 干扰加速种子萌发，增强根系发育和叶片光合作用能力。抑制 NtRAV-4 通过提高抗氧化防御能力和减少干旱胁迫下的相对电解质渗漏来提高耐旱性。这些结果增强了对 NtAP2/ERF 基因功能的理解，并将有助于提高烟草对胁迫的耐受性。
