College of Biological Science and Engineering, Jiangxi Agricultural University, Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Nanchang, 330045, China.
State Key Laboratory of Food Science and Resources, School of Food Science and Technology, Nanchang University, Nanchang, 330047, China.
Food Microbiol. 2025 Jan;125:104658. doi: 10.1016/j.fm.2024.104658. Epub 2024 Oct 12.
The objective of this study was to provide a promising alternative to chemical fungicides for management of postharvest citrus decay, thereby promoting sustainable citrus fruit production. The postharvest decay of citrus fruit caused by Penicillium digitatum and Penicillium italicum results in substantial economic losses in citrus industry worldwide. With growing fungal resistance issues in P. digitatum and P. italicum, there is an urgent need for searching new methods to address above problems in a safe and environmentally friendly way. Streptomyces sp. N2, a new species from Streptomyces genus, exhibits significant antagonistic activity against Rhizoctonia solani. However, its biocontrol efficacy against postharvest decay caused by P. digitatum and P. italicum and its action mechanism remain unknown. In this study, Streptomyces sp. N2 was found to have significant potential in controlling green and blue mold diseases in postharvest navel oranges. Moreover, the action mechanism of Streptomyces sp. N2 against both P. italicum and P. digitatum was elucidated. On the one hand, Streptomyces sp. N2 stimulated fruit resistance to fight against invading fungal pathogens. It significantly reduced ROS content in navel orange upon the infection of mold disease, increased the production of defense-related enzymes including peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) and pathogenesis-related proteins of chitinase and β-1,3-glucanase. On the other hand, Streptomyces sp. N2 secreted bioactive substances to inhibit the growth of P. italicum and P. digitatum so as to prevent the development of postharvest decay. The bioactive substances secreted by Streptomyces sp. N2 significantly inhibited the spore germination and mycelial growth and led to microstructural damages to the cell wall and membrane, ROS burst, and mitochondrial dysfunction in both P. italicum and P. digitatum. This study provides a theoretical reference and application potential for the biological control of Streptomyces sp. N2 on green and blue mold diseases.
本研究旨在为防治柑橘采后腐烂提供一种有前景的化学杀菌剂替代方法，从而促进柑橘的可持续生产。青霉和意大利青霉引起的柑橘果实采后腐烂给全球柑橘产业造成了巨大的经济损失。由于青霉和意大利青霉的真菌抗药性问题日益严重，因此迫切需要寻找新的方法，以安全、环保的方式解决这些问题。链霉菌属的一个新种链霉菌 N2 对丝核菌具有显著的拮抗活性。然而，其对青霉和意大利青霉引起的采后腐烂的生物防治效果及其作用机制尚不清楚。本研究发现链霉菌 N2 对采后脐橙青、绿霉病具有显著的控制潜力。此外，还阐明了链霉菌 N2 对青霉和意大利青霉的作用机制。一方面，链霉菌 N2 刺激果实抵抗入侵真菌病原体。它显著降低了感染青霉病时脐橙中的 ROS 含量，增加了防御相关酶（如过氧化物酶（POD）、多酚氧化酶（PPO）和苯丙氨酸解氨酶（PAL））和几丁质酶和β-1,3-葡聚糖酶的抗病相关蛋白的产生。另一方面，链霉菌 N2 分泌生物活性物质抑制青霉和意大利青霉的生长，从而防止采后腐烂的发生。链霉菌 N2 分泌的生物活性物质显著抑制青霉和意大利青霉的孢子萌发和菌丝生长，并导致细胞壁和细胞膜的微观结构损伤、ROS 爆发和线粒体功能障碍。本研究为链霉菌 N2 对青、绿霉病的生物防治提供了理论参考和应用潜力。
