Abstract: The AP2/ERF is one of the largest families of transcription factors in plants，which is involved in plant metabolic biosynthesis，organ development，stress response and hormone signal transduction.To explore the expression characteristics of ERF genes under low nitrogen stress in sesame，24 differentially expressed SiERF genes were identified from the former transcriptome result of sesame roots under low nitrogen stress，and their expression characteristics，co‐expression network and the expression profiles of the key gene SiERF08 under different treatments were analyzed.The results showed that the open reading frame length of 24 differentially expressed SiERF genes was 564—1 254 bp，protein molecular weight ranged from 20.92—44.97 ku，and isoelectric point ranged from 4. 39 to 10. 92. And 24 differentially expressed SiERF genes were unevenly distributed on 13 chromosomes.The promoter sequences contained a number of plant hormone response elements（ABRE，AuxRE and so on），stress response elements（such as ARE，DRE core and LTR），growth and development elements（O2‐site，Gap‐box and CAT‐box）and light response cis‐acting elements（G‐box，MRE，I‐box and so on）.The results of gene expression and Venn diagram showed that 24 and 14 differentially expressed SiERF genes were detected in Burmese prolific and Zhengzhi HL05，respectively.Among them，3 differentially expressed genes such as SiERF06 were identified in two varieties at 3，9 days after low nitrogen stress.Five key candidate genes in response to low nitrogen stress，such as SiERF08 were screened by co‐expression network analysis.The expression characteristics of key candidate gene SiERF08 under different stresses were analyzed.The results showed that，SiERF08 gene was induced under low nitrogen，drought，high salinity，GA and SA stresses，and under different treatments SiERF08 gene exhibited different expression patterns.The expression of SiERF08 gene was the highest in drought，high salt，SA，high temperature and low temperature treatment for 6 h，and reached the peak at 12 h under low nitrogen treatment.Under GA treatment，the expression of SiERF08 gene was only induced at 6 h and 72 h，and the difference was significant.Overall，24 differentially expressed SiERF genes under low nitrogen stress were analyzed by bioinformatics，and 5 key candidate genes such as SiERF08 were screened，among which SiERF08 gene was induced to express under low nitrogen，drought，high salinity and SA stress.This research will provide theoretical basis and genetic resources for further exploring SiERF genes function and revealing the molecular mechanism of low nitrogen tolerance in sesame.

Key words: Sesame, Low nitrogen stress, ERF transcription factor, Gene expression

摘要： AP2/ERF是植物最大的转录因子家族之一，参与植物代谢生物合成、器官发育、逆境响应和激素信号转导等过程。为了探究ERF基因在芝麻低氮胁迫下的表达特性，从前期芝麻根系低氮胁迫转录组中筛选出24个差异表达SiERF基因，对其进行表达特性和共表达网络分析，并分析了不同胁迫处理下SiERF08基因的表达特性。结果显示，24个差异表达SiERF基因开放阅读框（ORF）长度为564~1 254 bp，编码蛋白质的分子质量为20.92~44.97 ku，等电点4.39~10.92。24个差异表达SiERF基因不均匀地分布在13条染色体上。启动子区域包含植物激素响应元件（ABRE、AuxRE等）、逆境胁迫响应元件（ARE、DRE core、LTR等）、生长发育相关顺式作用元件（O2-site、Gap-box和CAT-box）和光响应元件（G-box、MRE、I-box等）。基因表达和韦恩图分析结果显示，低氮胁迫下，芝麻品种缅甸高产者和郑芝HL05分别检测到24个和14个差异表达SiERF基因，其中SiERF06等3个基因在2个品种低氮胁迫3、9 d均差异表达。通过共表达网络分析筛选出SiERF08等5 个低氮胁迫响应的关键候选基因。对关键候选基因SiERF08开展不同胁迫下的表达特性分析，结果显示，该基因在低氮、干旱、高盐、赤霉素及水杨酸等胁迫处理下被诱导表达，且不同胁迫处理下，SiERF08基因的表达模式不同。在干旱、高盐、水杨酸、高温和低温处理6 h，SiERF08基因的表达量最高；在低氮处理12 h，SiERF08基因表达量达到峰值；在赤霉素处理下，SiERF08基因在6 h和72 h诱导表达，且差异显著。综上所述，通过生物信息学手段对低氮胁迫下24个差异表达SiERF基因进行分析，筛选出SiERF08等5个关键候选基因，其中，SiERF08基因在低氮、干旱、高盐、水杨酸等胁迫下诱导表达，为深入探究芝麻SiERF基因功能、揭示芝麻耐低氮分子机制提供了理论依据和基因资源。

关键词: 芝麻, 低氮胁迫, ERF转录因子, 基因表达