Although Nicotiana tabacum represents a model plant for validating plant-pathogen interactions, few reports have focused on genes in this species that can effectively defend against tobacco brown spot (TBS) caused by Alternaria alternata. By identifying and analyzing key genes, we can gain a deeper understanding of how plants recognize Alternaria alternata and activate defense responses to resist pathogen invasion. Analyzing the functions and regulatory networks of the key genes for TBS resistance in tobacco will help improve the theoretical system of plant-pathogen interaction and provide new ideas for the prevention and control of other plant diseases. In the current study, search for key genes in the tobacco defence response to TBS, DX14 (resistant line) and ZY300 (susceptible line) were inoculated with A. alternata, and samples at 0 h, 48 h and 96 h were subjected to transcriptome sequencing. To determine the protein-protein interaction (PPI) networks of TF families, phytohormones, and kinases associated with pathogen defense, weighted correlation network analysis (WGCNA) was performed using the identified DEGs. Analysis of differentially expressed genes (DEGs) among transcription factor (TF) families, phytohormones, and kinases in the two lines revealed that there were more upregulated genes than downregulated genes in DX14 than in ZY300 and the physiological activity in response to TBS was most active at 48 h. In addition, multiple genes with significantly different expression levels in both lines were identified, and homologs of these genes in other species have been reported to be associated with plant disease resistance. Finally, we identified a bHLH (basic/helical loop-helix) TF, two WRKY TFs, and two ethylene synthase family genes in the mitogen-activated protein kinase (MAPK) signaling pathway, respectively. In this study, these were identified as hub genes associated with TBS defense and will be the focus of future validation.

中文翻译：

---

WGCNA 揭示了与 Nicotiana tabacum L 棕色斑点相关的综合基因共表达网络。

尽管 Nicotiana tabacum 代表了验证植物与病原体相互作用的模式植物，但很少有报道关注该物种中可以有效防御由链格孢菌引起的烟草褐斑病 （TBS） 的基因。通过识别和分析关键基因，我们可以更深入地了解植物如何识别链格孢菌并激活防御反应以抵抗病原体入侵。分析烟草中 TBS 抗性关键基因的功能和调控网络，有助于完善植物-病原菌相互作用的理论体系，为其他植物病害的防控提供新思路。在目前的研究中，寻找烟草防御对 TBS 反应的关键基因，DX14 （抗性系） 和 ZY300 （易感系） 接种了 A。 对 0 h 、 48 h 和 96 h 的样品进行转录组测序。为了确定与病原体防御相关的 TF 家族、植物激素和激酶的蛋白质-蛋白质相互作用 （PPI） 网络，使用鉴定的 DEGs 进行加权相关网络分析 （WGCNA）。对两系转录因子 （TF） 家族、植物激素和激酶中的差异表达基因 （DEGs） 分析显示，DX14 中上调的基因多于下调的基因，并且响应 TBS 的生理活性在 48 h 时最活跃。此外，在两个品系中鉴定出多个表达水平显著不同的基因，据报道这些基因在其他物种中的同源物与植物抗病性有关。 最后，我们分别在丝裂原活化蛋白激酶 （MAPK） 信号通路中鉴定了一个 bHLH （碱性/螺旋环-螺旋） TF 、两个 WRKY TFs 和两个乙烯合酶家族基因。在这项研究中，这些被确定为与 TBS 防御相关的枢纽基因，将成为未来验证的重点。