Luo Ziyi, Jia Yan, Guo Tianmeng, Li Haolong, Chen Jingying, Liu Airong, Ahammed Golam Jalal, Chen Shuangchen
College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang, 471023, PR China.
College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang, 471023, PR China.
Plant Physiol Biochem. 2025 Aug;225:110028. doi: 10.1016/j.plaphy.2025.110028. Epub 2025 May 14.
Root-knot nematode (RKN) infestation is a major threat to global agriculture, causing substantial damage to economically important crops such as tomatoes. Trichoderma species are promising biocontrol agents that can enhance plant growth, improve nutrient uptake, and induce systemic resistance against various pathogens, including RKNs. The R2R3-MYB transcription factor family plays a key role in plant secondary metabolism and defense mechanisms against biotic stressors. However, the specific role of tomato MYB108 in mediating resistance against RKNs remains underexplored. In this study, we found that RKN infestation decreases MYB108 expression, whereas Trichoderma harzianum inoculation significantly enhances MYB108 expression. Silencing MYB108 expression in tomato plants using the virus-induced gene silencing (VIGS) technique enhances susceptibility to RKNs as evidenced by a marked increase in gall number and root galling index (increased by 16.53 % and 16.10 %, respectively), alongside a reduction in the biocontrol efficacy of Trichoderma (decreased by 29 %). Furthermore, MYB108 silencing exacerbates RKN-induced oxidative stress, as evinced by elevated levels of hydrogen peroxide, superoxide anion, malondialdehyde, and electrolyte leakage. MYB108 silencing also attenuates the accumulation of key secondary metabolites such as flavonoids, phenols, and lignins, and reduces the activities of enzymes and the expression of genes associated with secondary metabolite synthesis. Although Trichoderma inoculation mitigates RKN-induced oxidative stress and enhances secondary metabolite synthesis, the silencing of MYB108 refutes the beneficial effects of Trichoderma on both secondary metabolite production and antioxidant capacity. Analysis of the transcriptional start site located 2000 base pairs upstream of the promoter regions of PAL, C4H, 4CL, and DFR reveals multiple MYB binding sites, indicating that MYB108 potentially plays a significant role in the transcriptional regulation of secondary metabolism. En masse, these findings highlight the critical role of MYB108 in mediating Trichoderma-induced resistance to RKNs and emphasize its potential as a target for enhancing plant resilience to RKNs.
根结线虫（RKN）侵染是全球农业面临的重大威胁，对番茄等经济作物造成严重损害。木霉菌是有前景的生物防治剂，可促进植物生长、改善养分吸收，并诱导对包括根结线虫在内的各种病原体的系统抗性。R2R3-MYB转录因子家族在植物次生代谢和抵御生物胁迫的防御机制中起关键作用。然而，番茄MYB108在介导对根结线虫抗性中的具体作用仍未得到充分研究。在本研究中，我们发现根结线虫侵染会降低MYB108的表达，而接种哈茨木霉会显著提高MYB108的表达。使用病毒诱导基因沉默（VIGS）技术沉默番茄植株中的MYB108表达会增强对根结线虫的易感性，这表现为虫瘿数量和根瘿指数显著增加（分别增加16.53%和16.10%），同时木霉菌的生物防治效果降低（降低29%）。此外，MYB108沉默会加剧根结线虫诱导的氧化应激，表现为过氧化氢、超氧阴离子、丙二醛水平升高和电解质渗漏增加。MYB108沉默还会减弱黄酮类、酚类和木质素等关键次生代谢物的积累，并降低与次生代谢物合成相关的酶活性和基因表达。尽管接种木霉菌可减轻根结线虫诱导的氧化应激并增强次生代谢物合成，但MYB108沉默否定了木霉菌对次生代谢物产生和抗氧化能力的有益影响。对位于PAL、C4H、4CL和DFR启动子区域上游2000个碱基对处的转录起始位点分析揭示了多个MYB结合位点，表明MYB108可能在次生代谢的转录调控中起重要作用。总体而言，这些发现突出了MYB108在介导木霉菌诱导的对根结线虫抗性中的关键作用，并强调了其作为增强植物对根结线虫抗性靶点的潜力。
