Guangdong Provincial Key Laboratory of Plant Adaptation and Molecular Design, School of Life Sciences, Guangzhou University, Guangzhou, 510006, China.
Guangdong Research Institute of Tobacco Science, Shaoguan, 512029, China.
BMC Plant Biol. 2023 Dec 6;23(1):620. doi: 10.1186/s12870-023-04633-w.
Tobacco bacterial wilt (TBW) caused by Ralstonia solanacearum is the most serious soil-borne disease of tobacco that significantly reduces crop yield. However, the limited availability of resistance in tobacco hinders breeding efforts for this disease.
In this study, we conducted hydroponic experiments for the root expression profiles of D101 (resistant) and Honghuadajinyuan (susceptible) cultivars in response to BW infection at 0 h, 6 h, 1 d, 3 d, and 7d to explore the defense mechanisms of BW resistance in tobacco. As a result, 20,711 and 16,663 (total: 23,568) differentially expressed genes (DEGs) were identified in the resistant and susceptible cultivars, respectively. In brief, at 6 h, 1 d, 3 d, and 7 d, the resistant cultivar showed upregulation of 1553, 1124, 2583, and 7512 genes, while the susceptible cultivar showed downregulation of 1213, 1295, 813, and 7735 genes. Similarly, across these time points, the resistant cultivar had downregulation of 1034, 749, 1686, and 11,086 genes, whereas the susceptible cultivar had upregulation of 1953, 1790, 2334, and 6380 genes. The resistant cultivar had more up-regulated genes at 3 d and 7 d than the susceptible cultivar, indicating that the resistant cultivar has a more robust defense response against the pathogen. The GO and KEGG enrichment analysis showed that these genes are involved in responses to oxidative stress, plant-pathogen interactions, cell walls, glutathione and phenylalanine metabolism, and plant hormone signal transduction. Among the DEGs, 239 potential candidate genes were detected, including 49 phenylpropane/flavonoids pathway-associated, 45 glutathione metabolic pathway-associated, 47 WRKY, 48 ERFs, eight ARFs, 26 pathogenesis-related genes (PRs), and 14 short-chain dehydrogenase/reductase genes. In addition, two highly expressed novel genes (MSTRG.61386-R1B-17 and MSTRG.61568) encoding nucleotide-binding site leucine-rich repeat (NBS-LRR) proteins were identified in both cultivars at 7 d.
This study revealed significant enrichment of DEGs in GO and KEGG terms linked to glutathione, flavonoids, and phenylpropane pathways, indicating the potential role of glutathione and flavonoids in early BW resistance in tobacco roots. These findings offer fundamental insight for further exploration of the genetic architecture and molecular mechanisms of BW resistance in tobacco and solanaceous plants at the molecular level.
由丁香假单胞菌烟草致病变种引起的烟草青枯病是烟草最严重的土传病害，显著降低了作物产量。然而，烟草中抗病性的有限可用性阻碍了对这种疾病的培育工作。
在这项研究中，我们进行了水培实验，以研究 D101（抗性）和红花大金元（感病）品种在 BW 感染 0 h、6 h、1 d、3 d 和 7 d 时的根表达谱，以探索烟草 BW 抗性的防御机制。结果，在抗性和感病品种中分别鉴定出 20711 个和 16663 个（总计：23568 个）差异表达基因（DEGs）。简而言之，在 6 h、1 d、3 d 和 7 d 时，抗性品种上调了 1553、1124、2583 和 7512 个基因，而感病品种下调了 1213、1295、813 和 7735 个基因。同样，在这些时间点上，抗性品种下调了 1034、749、1686 和 11086 个基因，而感病品种上调了 1953、1790、2334 和 6380 个基因。抗性品种在 3 d 和 7 d 时的上调基因多于感病品种，这表明抗性品种对病原体有更强的防御反应。GO 和 KEGG 富集分析表明，这些基因参与了对氧化应激、植物-病原体相互作用、细胞壁、谷胱甘肽和苯丙氨酸代谢以及植物激素信号转导的反应。在 DEGs 中，检测到 239 个潜在候选基因，包括 49 个苯丙烷/类黄酮途径相关、45 个谷胱甘肽代谢途径相关、47 个 WRKY、48 个 ERFs、8 个 ARFs、26 个病程相关基因（PR）和 14 个短链脱氢酶/还原酶基因。此外，在两个品种的 7 d 时，鉴定出两个高度表达的新基因（MSTRG.61386-R1B-17 和 MSTRG.61568），它们编码核苷酸结合位点富含亮氨酸重复（NBS-LRR）蛋白。
本研究揭示了与谷胱甘肽、类黄酮和苯丙烷途径相关的 GO 和 KEGG 术语中 DEGs 的显著富集，表明谷胱甘肽和类黄酮在烟草根中早期 BW 抗性中的潜在作用。这些发现为进一步探索烟草和茄科植物 BW 抗性的遗传结构和分子机制提供了基础，从分子水平上进行了研究。
