Duan Yanan, Ma Ziqing, Jia Yiwei, Xing Hengtong, Mao Zhiquan, Mao Ke, Zhang Zhijun, Li Chao, Ma Fengwang
State Key Laboratory for Crop Stress Resistance and High-Efficiency Production/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China.
College of Horticulture Science and Engineering, Shandong Agricultural University, National Key Laboratory of Crop Biology, Taian, 271018, Shangdong, China.
Stress Biol. 2025 Aug 25;5(1):51. doi: 10.1007/s44154-025-00246-5.
Apple replant disease (ARD) poses a serious threat to apple cultivation, primarily caused by the accumulation of Fusarium species. Bacillus species have demonstrated significant potential as microbial agents, with capabilities in promoting plant growth, suppressing soil-borne pathogens, and improving soil quality. Here in this study, strain LRB-5 was isolated from a healthy apple root system and identified as Bacillus vallismortis based on physiological and biochemical characterization and molecular sequencing analysis. It exhibited broad-spectrum antifungal activity against various Fusarium species, including F. oxysporum, F. moniliforme, F. proliferatum, and F. solani, with inhibition rates exceeding 65%. LRB-5 extracellular metabolites significantly inhibited Fusarium mycelial growth and spore germination. Greenhouse experiments demonstrated that LRB-5 reduced ARD disease severity by more than 50%. The volatile organic compounds produced by LRB-5 exhibited both antimicrobial activity and growth-promoting properties. Further assays revealed LRB-5 can secrete various cell wall-degrading enzymes and possesses plant growth-promoting capabilities. Pot experiments showed LRB-5 had excellent colonization ability in the rhizosphere of Malus hupehensis Rehd. seedlings, significantly increasing seedling biomass, soil bacterial and actinomycete populations, and the activity of root protective enzymes. Moreover, LRB-5 significantly enhanced the activity of soil enzymes while reducing the contents of phlorizin, benzoic acid, and p-hydroxybenzoic acid in the rhizosphere soil. Terminal restriction fragment length polymorphism and quantitative real-time PCR analyses revealed that LRB-5 improved bacterial carbon utilization, increased microbial diversity indices, reduced the abundance of Fusarium spp., and altered the structure of soil microbial communities. Collectively, these rusults suggest that LRB-5 effectively alleviated ARD by protecting apple roots from Fusarium infection and phenolic acid toxicity, optimizing soil microbial communities, and promoting plant growth. Future research should explore the combined application of LRB-5 with other control measures, thereby promoting its practical implementation.
苹果再植病（ARD）对苹果种植构成严重威胁，主要由镰刀菌属的积累引起。芽孢杆菌属已显示出作为微生物制剂的巨大潜力，具有促进植物生长、抑制土传病原体和改善土壤质量的能力。在本研究中，从健康苹果根系中分离出菌株LRB - 5，并通过生理生化特征和分子测序分析鉴定为死谷芽孢杆菌。它对多种镰刀菌属表现出广谱抗真菌活性，包括尖孢镰刀菌、串珠镰刀菌、轮枝镰刀菌和茄病镰刀菌，抑制率超过65%。LRB - 5胞外代谢产物显著抑制镰刀菌菌丝生长和孢子萌发。温室试验表明，LRB - 5使ARD病害严重程度降低了50%以上。LRB - 5产生的挥发性有机化合物具有抗菌活性和促生长特性。进一步分析表明，LRB - 5能分泌多种细胞壁降解酶并具有促进植物生长的能力。盆栽试验表明，LRB - 5在湖北海棠幼苗根际具有良好的定殖能力，显著增加了幼苗生物量、土壤细菌和放线菌数量以及根系保护酶的活性。此外，LRB - 5显著提高了土壤酶活性，同时降低了根际土壤中根皮苷、苯甲酸和对羟基苯甲酸的含量。末端限制性片段长度多态性分析和定量实时PCR分析表明，LRB - 5改善了细菌碳利用，增加了微生物多样性指数，降低了镰刀菌属的丰度，并改变了土壤微生物群落结构。总体而言，这些结果表明，LRB - 5通过保护苹果根系免受镰刀菌感染和酚酸毒性、优化土壤微生物群落以及促进植物生长，有效地减轻了ARD。未来的研究应探索LRB - 5与其他防治措施的联合应用，从而促进其实际应用。
