Although the use of crop-associated bacteria as biological control agents of fungal diseases has gained increasing interest, the biotechnological potential of forest tree-associated microbes and their natural products has scarcely been investigated. The objective of this study was to identify bacteria or bacterial products with antagonistic activity against Fusarium solani and Fusarium kuroshium, causal agent of Fusarium dieback, by screening the rhizosphere and phyllosphere of three Lauraceae species. From 195 bacterial isolates, we identified 32 isolates that significantly reduced the growth of F. solani in vitro, which mostly belonged to bacterial taxa Bacillus, Pseudomonas and Actinobacteria. The antifungal activity of their volatile organic compounds (VOCs) was also evaluated. Bacterial strain Bacillus sp. CCeRi1-002, recovered from the rhizosphere of Aiouea effusa, showed the highest percentage of direct inhibition (62.5 %) of F. solani and produced diffusible compounds that significantly reduced its mycelial growth. HPLC-MS analyses on this strain allowed to tentatively identify bioactive compounds from three lipopeptide groups (iturin, surfactin and fengycin). Bacillus sp. CCeRi1-002 and another strain identified as Pseudomonas sp. significantly inhibited F. solani mycelial growth through the emission of VOCs. Chemical analysis of their volatile profiles indicated the likely presence of 2-nonanone, 2-undecanone, disulfide dimethyl and 1-butanol 3-methyl-, which had been previously reported with antifungal activity. In antagonism assays against F. kuroshium, Bacillus sp. CCeRi1-002 and its diffusible compounds exhibited significant antifungal activity and induced hyphal deformations. Our findings highlight the importance of considering bacteria associated with forest species and the need to include bacterial products in the search for potential antagonists of Fusarium dieback.

尽管使用农作物相关细菌作为真菌疾病的生物防治剂的兴趣日益浓厚，但几乎没有研究林木相关微生物及其天然产物的生物技术潜力。这项研究的目的是通过筛选三个月桂科物种的根际和根际，鉴定对枯萎镰刀菌的病原体茄枯萎病和枯萎病具有拮抗活性的细菌或细菌。从195个细菌菌株中，我们鉴定了32个在体外显着降低茄形镰刀菌生长的菌株，这些菌株主要属于细菌类群Bacillus，Pseudomonas和放线菌。还评估了其挥发性有机化合物（VOC）的抗真菌活性。细菌菌株芽孢杆菌属。从Aiouea effusa的根际中回收的CCeRi1-002显示出最高的抑制率（62.5％），对sol。F. solani产生了可扩散的化合物，从而大大降低了其菌丝体的生长。对该菌株进行HPLC-MS分析，可以从三个脂肽基团（伊图蛋白，表面活性素和丰霉素）中初步鉴定出生物活性化合物。芽孢杆菌属。CCeRi1-002和另一个鉴定为假单胞菌属的菌株。显着抑制茄通过释放挥发性有机化合物引起菌丝体生长。对它们的挥发性特征进行化学分析表明，可能存在2-壬酮，2-十一烷酮，二硫化二甲基和1-丁醇3-甲基-，先前已报道它们具有抗真菌活性。在对库氏镰刀菌，芽孢杆菌的拮抗试验中。CCeRi1-002及其可扩散化合物表现出显着的抗真菌活性并引起菌丝变形。我们的发现强调了考虑与森林物种有关的细菌的重要性，以及在寻找潜在的枯萎镰刀菌拮抗物时必须包括细菌产品。