Yan Jingyi, Zhao Tongshu, Chen Yi, Liu Haiheng, Wei Chunhua, Ma Jianxiang, Zhang Yong, Yang Jianqiang, Zhang Xian, Li Hao
State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Horticulture, Northwest A&F University, Yangling, China.
Xi'an Modern Agricultural Science and Technology Exhibition Center, Xi'an Agricultural Technology Extension Center, Xi'an, China.
Front Plant Sci. 2025 May 1;16:1508852. doi: 10.3389/fpls.2025.1508852. eCollection 2025.
wilt, caused by the soil-borne fungal pathogen (Fo), is widely recognized as one of the most devastating fungal diseases, inflicting significant damage on a wide range of agricultural and horticultural crops. Despite melatonin has recently emerged as a potential enhancer of plant resistance against Fo, the underlying mechanisms remain elusive. In this study, our results demonstrate that exogenous melatonin and MeJA enhance watermelon resistance against f. sp. race 2 (FON2) in a dose-dependent manner. The optimal concentration for melatonin and MeJA was determined to be 10 μM and 1 μM, respectively. Both melatonin and MeJA inhibited FON2 mycelial growth on PDA medium in a dose-dependent manner. Furthermore, exogenous melatonin significantly stimulated upregulation of MeJA synthesis genes and increased MeJA content upon FON2 infection. However, pretreatment with a MeJA synthesis inhibitor (DIECA) suppressed the induction of melatonin-induced resistance against FON2. Furthermore, MeJA also induced the upregulation of melatonin biosynthetic gene () and increased melatonin accumulation in response to FON2. Notably, the reduction in FON2 resistance caused by deletion was completely restored through exogenous application of MeJA. These results suggest that melatonin facilitates MeJA accumulation, which provides feedback to promote melatonin accumulation, forming a reciprocal positive regulatory loop in response to FON2 infection. Additionally, polyphenol oxidase, phenylalanine ammonia lyase, and lignin are involved in the MeJA-induced resistance against FON2. The growing concern over minimizing pesticide usage and transitioning to sustainable and natural control strategies underscores the significant potential of such a mechanism in combating Fo.
由土壤传播的真菌病原体（尖孢镰刀菌）引起的枯萎病被广泛认为是最具毁灭性的真菌病害之一，对多种农业和园艺作物造成重大损害。尽管褪黑素最近已成为植物抗尖孢镰刀菌的潜在增强剂，但其潜在机制仍不清楚。在本研究中，我们的结果表明，外源褪黑素和茉莉酸甲酯以剂量依赖的方式增强西瓜对尖孢镰刀菌2号生理小种（FON2）的抗性。褪黑素和茉莉酸甲酯的最佳浓度分别确定为10 μM和1 μM。褪黑素和茉莉酸甲酯均以剂量依赖的方式抑制FON2在PDA培养基上的菌丝生长。此外，外源褪黑素在FON2感染后显著刺激茉莉酸甲酯合成基因的上调并增加茉莉酸甲酯含量。然而，用茉莉酸甲酯合成抑制剂（DIECA）预处理可抑制褪黑素诱导的对FON2抗性的诱导。此外，茉莉酸甲酯还诱导褪黑素生物合成基因（）的上调，并在响应FON2时增加褪黑素积累。值得注意的是，通过外源施用茉莉酸甲酯完全恢复了因（基因）缺失导致的对FON2抗性的降低。这些结果表明，褪黑素促进茉莉酸甲酯积累，这提供反馈以促进褪黑素积累，在响应FON2感染时形成一个相互的正调控环。此外，多酚氧化酶、苯丙氨酸解氨酶和木质素参与茉莉酸甲酯诱导的对FON2的抗性。对尽量减少农药使用并转向可持续和自然控制策略的日益关注突出了这种机制在对抗尖孢镰刀菌方面的巨大潜力。
