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Verticillium wilt , a serious fungal disease affecting cotton, is often referred to as the "cancer of cotton" due to its severe impact on cotton yield and quality. Zinc oxide nanoparticles (ZnO-NPs) are known to boost crop resistance to diseases, but their effectiveness against cotton's Verticillium wilt is not well understood. To address this gap, this study assessed the impacts of ZnO-NPs on cotton growth, physiological responses , and transcriptomic profiles following inoculation with Verticillium dahliae . The inhibitory effect of ZnO-NPs on Verticillium dahliae was concentration-dependent, and the inhibitory effect increased with increasing concentrations of ZnO-NPs, with 200 mg·L −1 being the most effectiver, reducing the disease index by 36.16 % compared to the control treatment (0 mg·L −1 ). Compared with no treatment, ZnO-NPs treatment reduced the levels of H 2 O 2 , O 2 - in roots and leaves, and malondialdehyde at 48 hours post-inoculation, and increased the activities of superoxide dismutase and catalase . The application of ZnO-NPs also increased the activities of defense-related enzymes in cotton, including phenylalanine ammonia lyase, polyphenol oxidase , and β-1,3-glucanase. The ZnO-NPs treatment resulted in a significant increase in lignin content and various hormone levels (auxin, salicylic acid, jasmonic acid , and melatonin) in the roots, while concurrently reducing ethylene levels. Transcriptomic analysis revealed that ZnO-NPs can enhance cotton’s resistance to Verticillium wilt by regulating genes involved in immune responses, antioxidant activities , plant-pathogen interactions, MAPK signaling, hormone signaling, and phenylpropanoid biosynthesis pathways, thereby increasing resistance to. These findings indicate that ZnO-NPs at the optimal concentration of 200 mg·L -1 could serve as an effective nanopesticides for managing Verticillium wilt in cotton.
Zhu et al. (Tue,) studied this question.