BACKGROUNDIdentifying effective biological control agents against fungal pathogens and determining their mechanisms of action are important in the control of plant diseases.RESULTSIn this study, we isolated an endophytic bacterial strain, GsB01, from the branches of asymptomatic Gleditsia sinensis. Multi‐locus sequence analysis identified the strain as Bacillus velezensis. GsB01 exhibited significant antifungal activity against Thyronectria austroamericana, the causative agent of G. sinensis wilt. Liquid chromatography‐mass spectrometry identified four consistently present antimicrobial compounds in GsB01 metabolite fractions with high antifungal activity: macrolactin A, bacillaene A, surfactin, and iturin. GsB01's active metabolite fractions altered the metabolic profiles of T. austroamericana, disrupting seven pathways, including arginine biosynthesis, nucleotide metabolism, purine metabolism, and the pentose phosphate pathway. Furthermore, absolute quantitative polymerase chain reaction analysis suggested that GsB01 may increase the abundance of endophytic bacteria in G. sinensis. The 16S rRNA amplicon sequencing revealed changes in the endophytic landscape in stems and roots following GsB01 introduction, particularly with significant variation in the dominant bacterial genera within the stems.CONCLUSIONThe study highlights GsB01's potential against plant wilt and suggests that its antifungal activity is achieved by secreting antifungal metabolites. The study also recorded changes in the symbiotic microbiota within trees that had been infected with a pathogenic fungus and subsequently treated with an endophytic antagonistic bacterial strain. © 2024 Society of Chemical Industry.

中文翻译：

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内生芽孢杆菌 GsB01 通过分泌抗真菌代谢物来控制 Gleditsia sinensis 枯萎病，并调节树木内的共生微生物群


背景识别针对真菌病原体的有效生物防治剂并确定其作用机制对于控制植物病害很重要。结果本研究从无症状的 Gleditsia sinensis 的分支中分离出一种内生细菌菌株 GsB01。多位点序列分析确定该菌株为 Bacillus velezensis。GsB01 对 G. sinensis 枯萎病的病原体 Thyronectria austroamericana 表现出显着的抗真菌活性。液相色谱-质谱法在 GsB01 代谢物组分中鉴定出四种始终存在的具有高抗真菌活性的抗菌化合物：素 A、杆菌烯 A、表面活性素和伊图林。GsB01 的活性代谢物组分改变了南美洲戟的代谢特征，破坏了七种途径，包括精氨酸生物合成、核苷酸代谢、嘌呤代谢和磷酸戊糖途径。此外，绝对定量聚合酶链反应分析表明，GsB01 可能增加 GsB01 中内生细菌的丰度。16S rRNA 扩增子测序揭示了 GsB01 引入后茎和根内生植物景观的变化，特别是茎内优势细菌属的显著变化。结论该研究强调了 GsB01 对抗植物枯萎病的潜力，并表明其抗真菌活性是通过分泌抗真菌代谢物来实现的。该研究还记录了被病原真菌感染并随后用内生菌拮抗细菌菌株处理的树木内共生微生物群的变化。© 2024 化工学会.