Secondary wall-associated NAC (SWN) genes are a subgroup of NAC (NAM, ATAF, and CUC) transcription factors (TF) that play a key role in regulating secondary cell wall biosynthesis in plants. However, this gene family has not been systematically characterized, and their potential roles in response to hormones are unknown in Nicotiana tabacum. In this study, a total of 40 SWN genes, of which 12 from Nicotiana tomentosiformis, 13 from Nicotiana sylvestris, and 15 from Nicotiana tabacum, were successfully identified. The 15 SWNs from Nicotiana tabacum were further classified into three groups, namely, vascular-related NAC domain genes (NtVNDs), NAC secondary wall thickening promoting factor genes (NtNSTs), and secondary wall-associated NAC domain genes (NtSNDs). The protein characteristic, gene structure, and chromosomal location of 15 NtSWNs (also named Nt1 to Nt15) were also analyzed. The NtVND and NtNST group genes had five conserved subdomains in their N-terminal regions and a motif (LP[Q/x] L[E/x] S[P/A]) in their diverged C- terminal regions. Some hormones, dark and low-temperature related cis-acting elements, were significantly enriched in the promoters of NtSWN genes. A comprehensive expression profile analysis revealed that Nt4 and Nt12 might play a role in vein development. Others might be important for stem development. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) revealed that in the NtNST group, genes such as Nt7, Nt8, and Nt13 were more sensitive than the genes in NtVND and NtSND groups under abiotic stress conditions. A transactivation assay further suggested that Nt7, Nt8, and Nt13 showed a significant transactivation activity. Overall, SWN genes were finally identified and characterized in diploid and tetraploid tobacco, revealing new insights into their evolution, variation, and homology relationships. Transcriptome, cis-acting element, qRT-PCR, and transactivation assay analysis indicated the roles in hormonal and stress responses, which provided further resources in molecular mechanism and genetic improvement.

次生壁相关 NAC (西南网)基因是 NAC（NAM、ATAF 和 CUC）转录因子 (TF) 的一个亚群，它们在调节植物次生细胞壁生物合成中起关键作用。然而，该基因家族尚未被系统地表征，它们在响应激素方面的潜在作用尚不清楚。烟草. 在本研究中，共有 40西南网 基因，其中 12 个来自 绒毛烟草, 13 来自 烟草, 和 15 从 烟草，被成功识别。15SWN 从 烟草 进一步分为三组，即血管相关的 NAC 域基因（NtVND)、NAC次生壁增厚促进因子基因(NtNST), 和次生壁相关 NAC 域基因 (NtSND）。15的蛋白质​​特征、基因结构和染色体位置NtSWN （也称 Nt1 到 Nt15) 也进行了分析。这越南盾 和 NST组基因在它们的 N 端区域有五个保守的子域，在它们不同的 C 端区域有一个基序 (LP[Q/x] L[E/x] S[P/A])。一些激素，与黑暗和低温有关顺式- 作用元素，显着丰富的启动子 新南威尔士州基因。全面的表达谱分析表明，Nt4 和 Nt12可能在静脉发育中发挥作用。其他的可能对茎的发育很重要。定量逆转录聚合酶链反应 (qRT-PCR) 表明，在NST 组，基因，如 Nt7, Nt8， 和 Nt13 比基因更敏感 越南盾 和 NtSND非生物胁迫条件下的群体。反式激活试验进一步表明Nt7, Nt8， 和 Nt13显示出显着的反式激活活性。总体，西南网基因最终在二倍体和四倍体烟草中被鉴定和表征，揭示了对它们的进化、变异和同源关系的新见解。转录组，顺式作用元件、qRT-PCR 和反式激活测定分析表明在激素和应激反应中的作用，这为分子机制和遗传改良提供了进一步的资源。