MYB transcription factors (TFs) play important roles in plant growth and development, metabolic regulation, and stress responses. In the current study, 258 2R-MYB TFs were identified in Nicotiana tabacum and systemically analyzed. The 2R-NtMYB TFs were unevenly distributed on 23 chromosomes and were classified into 33 subgroups according to the Arabidopsis thaliana 2R-MYB classification. The promoters of the 2R-NtMYB harbor numerous potential cis-acting elements involved in plant growth, metabolism, hormone signaling, and stress responsiveness. Chip-based expression profiling of different tissues and growth stages revealed that the 2R-NtMYBs showed constitutive or spatiotemporally specific expressions. RNA-sequencing data indicated that some 2R-NtMYBs, including NtMYB16, NtMYB27, NtMYB35, and NtMYB170, are involved in the response to one or several abiotic and biotic stresses, namely drought and resistance to black shank and bacterial wilt. Quantitative PCR results further revealed that NtMYBs respond to different hormones (abscisic acid, indole acetic acid, gibberellic acid, methyl jasmonate, and salicylic acid) and confirmed their involvement in abiotic stress responses like heat, drought, and salt. NtMYB35 overexpression and mutant lines generated using CRISPR-Cas9 gene editing were used to verify the important role of NtMYB35 in regulating tobacco growth, pigment metabolism, and aphid resistance. These results provide a detailed overview of this TF family in N. tabacum and valuable insights for future functional analyses of NtMYB TFs.

中文翻译：

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烟草2R-MYB家族的综合分析及NtMYB35在色素代谢中的功能表征

MYB转录因子（TF）在植物生长发育、代谢调节和胁迫反应中发挥着重要作用。在当前的研究中，在烟草中鉴定出了 258 个 2R-MYB TF ，并进行了系统分析。2R-NtMYB 转录因子不均匀地分布在 23 条染色体上，根据拟南芥2R-MYB 分类分为 33 个亚类。2R-NtMYB的启动子含有许多潜在的顺式作用元件，涉及植物生长、代谢、激素信号传导和应激反应。基于芯片的不同组织和生长阶段的表达谱显示，2R-NtMYB显示出组成型或时空特异性表达。RNA测序数据表明，一些2R-NtMYB，包括NtMYB16、NtMYB27、NtMYB35和NtMYB170，参与对一种或多种非生物和生物胁迫的响应，即干旱以及对黑胫病和青枯病的抵抗。定量PCR结果进一步揭示NtMYB对不同激素（脱落酸、吲哚乙酸、赤霉酸、茉莉酸甲酯和水杨酸）有反应，并证实它们参与热、干旱和盐等非生物胁迫反应。利用NtMYB35过表达和使用CRISPR-Cas9基因编辑产生的突变株系来验证NtMYB35在调节烟草生长、色素代谢和蚜虫抗性中的重要作用。这些结果提供了烟草中该 TF 家族的详细概述，并为 NtMYB TF 的未来功能分析提供了宝贵的见解。