The AP2/ERF transcription factors (TFs) regulate various processes of plant growth, development, and response to environmental stimuli. Although they have been extensively documented in many plants, little is known about stress responsive APETALA2/ethylene response factor (AP2/ERF) genes in sweetpotato (Ipomoea batatas L.). In this study, 20 putative AP2/ERF genes, named IbERF1, IbERF2, and IbERF5–IbERF23 were identified based on the salt‐treated RNA‐seq data from two sweetpotato cultivars with different salt tolerance. Phylogenetic analysis and sequence characterization identified that all the screened IbERF proteins contained a conserved AP2 domain, which belonged to dehydration‐responsive element binding proteins (DREB; 7 members) or ERF (13 members) subfamily. The systematic expression analysis of 12 mainly salt‐induced IbERFs by quantitative real‐time polymerase chain reaction (qRT‐PCR) revealed that most IbERFs were remarkably increased by multiple abiotic stresses, such as NaCl, dehydration, and cold stress. Furthermore, varying degrees of upregulation were also detected in the expression of most IbERFs when treated with hormone abscisic acid, jasmonic acid, and salicylic acid. The expression profiles of IbERFs corroborate their involvement in diverse biological processes. In addition, the IbERF5, which was exclusively upregulated by the treatments, was identified as a nuclear protein without transcriptional activation activity. Collectively, the data of stress responsive IbERFs will provide valuable knowledge for further functional studies of IbERFs in sweetpotato stress tolerance.

中文翻译：

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甘薯AP2 / ERF转录因子盐胁迫响应基因的鉴定，表达分析和功能表征

AP2 / ERF转录因子（TF）调节植物生长，发育和对环境刺激的反应的各种过程。尽管它们已经在许多植物中得到了广泛的文献报道，但对甘薯（番薯（Ipomoea batatas L.））中的胁迫响应性APETALA2 /乙烯响应因子（AP2 / ERF）基因知之甚少。在这项研究中，有20个假定的AP2 / ERF基因，分别称为IbERF1，IbERF2和IbERF5-IbERF23根据两个耐盐性不同的甘薯品种的盐处理RNA-seq数据鉴定。系统进化分析和序列鉴定表明，所有筛选的IbERF蛋白均包含一个保守的AP2域，属于脱水反应性元素结合蛋白（DREB； 7个成员）或ERF（13个成员）亚家族。通过定量实时聚合酶链反应（qRT-PCR）对12种主要由盐诱导的IbERF进行的系统表达分析表明，大多数IbERF均由于多种非生物胁迫（例如NaCl，脱水和冷胁迫）而显着增加。此外，在大多数IbERF的表达中也检测到不同程度的上调用激素脱落酸，茉莉酸和水杨酸治疗。IbERF的表达谱证实了它们参与了多种生物过程。此外，被治疗独家上调的IbERF5被鉴定为无转录激活活性的核蛋白。总的来说，应激反应性IbERF的数据将为进一步研究IbERF在甘薯胁迫耐受性中的功能提供有价值的知识。