Abstract Brown blotch disease of mushroom caused by Pseudomonas tolaasii, often results of severe damage to mushroom tissues. In this study, the biocontrol mechanisms mediated by endofungal bacteria Pseudomonas sp. De1, Bacillus sp. De3, Pseudomonas sp. Bi1 and Pantoea sp. Ma3 previously isolated from wild growing mushrooms against Pseudomonas tolaasii Pt18 were demonstrated. Our results provide evidence that all bacterial strains can colonize mycelia of Agaricus bisporus. All endogungal bacteria except Pseudomonas sp. Bi1 contained one or more genes encoding antibiotic production. The non-volatile compounds of endofungal bacteria significantly inhibited the biofilm formation by P. tolaasii Pt18. Results showed that all strains except Pantoea sp. Ma3 are capable of detoxify tolaasin, a major virulence factor produced by P. tolaasii Pt18. We also showed that all endofungal bacteria tested were able to significantly decrease the browning symptoms of pretreated-mushroom caps compared to inoculated caps with P. tolaasii alone. AbPPO3 gene expression levels in mycelia and fruiting bodies of A. bisporus significantly increased after P. tolaasii Pt18 inoculation. Our findings indicated that The relative expression level of AbPPO3 gene decreased in the mushroom mycelia and fruiting bodies pretreated with Pantoea sp. Ma3 and Pseudomonas sp. Bi1 strains, and the levels were significantly lower than mushroom tissues treated with P. tolaasii Pt18 alone. Overall, the findings presented in this study revealed the efficacy of the selected endofungal bacteria in biocontrol activity against P. tolaasii and the possible use of these strains as a safe microbial agents in mushroom brown blotch disease management.

中文翻译：

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用内源性细菌治疗托拉假单胞菌感染的双孢蘑菇褐斑病和酪氨酸酶活性降低

摘要 由托拉假单胞菌（Pseudomonas tolaasii）引起的蘑菇褐斑病，往往是蘑菇组织受到严重破坏的结果。在这项研究中，由内生真菌假单胞菌介导的生物防治机制。De1，芽孢杆菌属。De3，假单胞菌属。Bi1 和 Pantoea sp。Ma3 先前从野生蘑菇中分离出来的对抗 Pseudomonas tolaasii Pt18 得到了证明。我们的研究结果提供了所有细菌菌株都可以定殖双孢蘑菇菌丝体的证据。除假单胞菌外的所有细菌。Bi1 包含一个或多个编码抗生素生产的基因。真菌内细菌的非挥发性化合物显着抑制了 P. tolaasii Pt18 的生物膜形成。结果表明，除 Pantoea sp. 外的所有菌株。Ma3 能够解毒 tolaasin，这是一种由 P. tolaasii Pt18 产生的主要毒力因子。我们还表明，与单独接种 P. tolaasii 的菌盖相比，所有测试的真菌内细菌都能够显着减少预处理蘑菇菌盖的褐变症状。接种 P. tolaasii Pt18 后，双孢蘑菇菌丝体和子实体中的 AbPPO3 基因表达水平显着增加。我们的研究结果表明，AbPPO3 基因的相对表达水平在用 Pantoea sp 预处理的蘑菇菌丝体和子实体中降低。Ma3 和假单胞菌属。Bi1 菌株，其水平显着低于单独用 P. tolaasii Pt18 处理的蘑菇组织。总体而言，本研究中提出的发现揭示了选定的真菌内细菌对 P. p. 的生物防治活性的功效。