酚酸降解菌耐盐芽胞杆菌YNK-FB0022对番茄枯萎病罹病土壤微生物多样性的影响OA

[Objective]To clarify the regulatory effect of salt-tolerant Bacillus halotolerans YNK-FB0022 with phenolic acid-degrading activity on the microbial diversity and community structure of diseased soil,verify its control efficacy against tomato fusarium wilt,and provide a theoretical basis for the biological control of tomato fusarium wilt in continuous cropping systems.[Method]In this study,continuous cropping soil frequently affected by tomato fusarium wilt was collected from the Honghe region,and four indoor pot experiment treatments were set up:blank control group(CK),benzoic acid addition group(CK1,simulating the phenolic acid accumulation stress environment in continuous cropping soil),benzoic acid+YNK-FB0022 bacterial solution addition group(T1),and YNK-FB0022 bacterial solution addition group(T2).By determining the disease index of tomato fusarium wilt and agronomic traits,analyzing soil physicochemical properties,the control mechanism of salt-tolerant Bacillus halotolerans YNK-FB0022 on tomato fusarium wilt was clarified.[Result]Compared with CK,the YNK-FB0022 bacterial solution treatment significantly increased tomato plant height(15.92%),stem diameter(10.92%),and root length(11.45%)(P<0.05);the activities of sucrase,urease,and acid phosphatase—key enzymes involved in soil carbon,nitrogen,and phosphorus cycles—significantly increased by 33.25%,72.06%,and 74.69%(P<0.05),respectively.Under T2 treatment,the Ace index of bacterial α-diversity significantly increased by 12.07%compared with CK,while the fungal Ace index and Chao1 index significantly decreased by 17.83% and 16.52%respectively.Beta diversity PCA analysis showed that the bacterial and fungal communities in T2 treatment were significantly separated from those in CK and CK1 treatments,while the communities in CK and CK1 treatments had high aggregation and no significant difference(P<0.05).The results of microbial community structure showed that the abundance of Actinobacteriota(a dominant bacterial phylum)and Glomeromycota(a dominant fungal phylum)significantly increased;the composition of bacterial community structure had a significant impact on the disease index of tomato fusarium wilt,and the strain treatment increased the complexity of the bacterial network structure.The results of SEM analysis indicated that YNK-FB0022 reduced the disease index of tomato fusarium wilt by improving soil physicochemical indicators,increasing soil enzyme activities,and enhancing the complexity of microbial network structure,thereby achieving disease control.[Conclusion]Salt-tolerant Bacillus halotolerans YNK-FB0022 demonstrates a promising control effect on tomato fusarium wilt by improving soil physicochemical properties,enhancing soil enzyme activities,effectively regulating the microbial diversity and community structure of diseased soil,and increasing the complexity of microbial network structure.It is a biocontrol strain with great potential.