防治卵孢小奥德蘑蛛网病生防菌筛选及其基因组分析

Screening and genomic analysis of biocontrol bacteria against cobweb disease of Oudemansiella raphanipes

摘要:

卵孢小奥德蘑(Oudemansiella raphanipes)是一种食药兼用的珍稀食用菌，但其易受到异形枝葡霉(Cladobotryum varium)引起的蛛网病侵害。目的 获得能够生物防控蛛网病且促进卵孢小奥德蘑生长的覆土细菌。方法 从卵孢小奥德蘑覆土中分离细菌，检测其对卵孢小奥德蘑及蛛网病菌的拮抗活性，筛选出具有防病促生的多功能菌株，并基于基因组数据分析明确其潜在的生物机制。结果 从覆土中共分离获得90株细菌，其中38株细菌对异形枝葡霉具有明显的抑制活性，且对卵孢小奥德蘑无抑制活性。进一步筛选发现，2株细菌的上清液不仅显著促进卵孢小奥德蘑菌丝的生长，还能显著抑制异形枝葡霉菌丝的生长。基于基因组数据分析，鉴定出上述2株细菌分别为简单近芽孢杆菌(Peribacillus simplex)与根际苍白杆菌(Ochrobactrum rhizosphaerae)，且它们含有多种功能基因与次级代谢产物基因簇。结论 本研究获得2株具有食用菌防病促生功能的细菌，为未来蛛网病的生态防控储备了有益微生物资源。

Abstract:

Oudemansiella raphanipes is a rare edible and medicinal mushroom, while it is highly susceptible to cobweb disease caused by Cladobotryum varium.Objective To obtain bacteria capable of controlling cobweb disease and promoting the mycelial growth of O. raphanipes from casing soil.Methods Bacteria were isolated from the casing soil of O. raphanipes, and their antagonistic activity against the mycelial growth of both O. raphanipes and C. varium was evaluated. The strains with disease-preventing and growth-promoting properties were screened out, and their functioning mechanisms were studied based on genome data.Results A total of 90 bacterial strains were isolated from the casing soil, of which 38 strains showed significant inhibitory activity against the mycelial growth of C. varium and no inhibitory activity against that of O. raphanipes. The supernatants of two strains significantly inhibited the mycelial growth of C. varium and promoted that of O. raphanipes. Based on the genome data, the above two strains were identified as Peribacillus simplex and Ochrobactrum rhizosphaerae, respectively, and they carried multiple functional genes and biosynthetic gene clusters of secondary metabolites.Conclusion Two bacterial strains capable of controlling the disease and promoting the growth of edible fungi were obtained, providing valuable microbial resources for the future biocontrol of cobweb disease.