Utilising the rhizosphere microbiota as a biological control agent is a promising strategy to protect plants against pathogens, although its efficacy in fungal hosts is uncertain. This study investigated the efficacy of Pseudomonas chlororaphis, a bacterial strain, in mitigating Paecilomyces penicillatus, a soil-borne pathogenic fungus responsible for white mould disease (WMD) in cultivated morels, such as Morchella importuna. Soils with chronic WMD, inoculated with or without P. chlororaphis, were utilised for M. importuna cultivation. In P. chlororaphis-inoculated morel soil beds, P. chlororaphis colonised both the mycelial surface and ascocarp matrix of M. importuna, increasing the abundance of Morchella in soil and the α-diversity of the soil fungal community. Additionally, P. chlororaphis inoculation decreased the abundance of detrimental P. penicillatus and mitigated the WMD incidence, which correspondingly increased the morel yield. Metagenomics revealed that increasing the pseudomonads in the M. importuna mycosphere altered the functionalities of the M. importuna soil microbiota, enhancing the abundances of genes encoding chitinase and alkaline protease and reducing the abundances of genes encoding glucanase and laccase. Under P. chlororaphis inoculation, pathways associated with pathogenic invasion were under-represented in the soil microbiota. These results enhance our understanding of bacterial–fungal interactions within soil ecosystems and demonstrate the potential for disease suppression through microbiota manipulation within the fungal mycosphere. These insights may lead to innovative approaches to combat fungal pathogens and enhance the health and productivity of valuable fungal crops such as morels.

利用根际微生物群作为生物控制剂是保护植物免受病原体侵害的一种很有前途的策略，尽管它在真菌宿主中的功效尚不确定。本研究调查了细菌菌株氯拉假单胞菌在减轻青霉拟苗方面的功效，青霉拟苗是一种导致栽培羊肚菌（如 Morchella importuna）中白霉病 （WMD） 的土壤传播病原真菌。患有慢性 WMD 的土壤，接种或接种 P. chlororaphis，用于 M. importuna 种植。在接种的 P. chlororaphis 羊肚菌土壤床中，P. chlororaphis 定植于 M. importuna 的菌丝表面和子囊果基质，增加了土壤中 Morchella 的丰度和土壤真菌群落的α多样性。此外，接种 P. chlororaphis 降低了有害 P. penicillatus 的丰度并减轻了 WMD 的发病率，从而相应地提高了羊肚菌的产量。宏基因组学显示，增加 M. importuna 菌际球中的假单胞菌改变了 M. importuna 土壤微生物群的功能，增强了编码几丁质酶和碱性蛋白酶的基因的丰度，降低了编码葡聚糖酶和漆酶的基因的丰度。在 P. chlororaphis 接种下，与病原入侵相关的途径在土壤微生物群中代表性不足。这些结果增强了我们对土壤生态系统中细菌-真菌相互作用的理解，并证明了通过真菌支气圈内的微生物群操纵来抑制疾病的潜力。 这些见解可能会导致对抗真菌病原体的创新方法，并提高羊肚菌等有价值的真菌作物的健康和生产力。