Effect Of Epibiotic Microorganism On Pathogenicity Of Pathogenic Fungi To Solenopsis Invicta Buren And Its Diversity Analysis

Solenopsis invicta Buren is one of the 100 most harmful invasive species.It causes serious harm to agriculture,forestry,public facilities and safety of human and ecosystem.In this paper,the effect of the surface-microorganism of S.invicta on the pathogenicity of Beauveria bassiana and Metarhizium anisopliae to S.invicta were studied.And in-depth study on the diversity of S.invicta surface-microorganisms.The inhibition of surface-microorganisms to pathogens fungi were determined.It was supply theoretical foundation for using pathogenic fungi to control S.invicta.All results as follows:1)The effect of surface-microorganisms of S.invicta on the pathogenicity of B.bassiana and M.anisopliae to S.invicta by spraying inoculation were determined.The results showed that the corrected mortality rates of surface-treated S.invicta were significant higher than untreated after inoculation with B.bassiana BSX-PC 1.0×10⁶spores·m L^-1 for 7 d,with the corrected mortality rates were 61.52%,43.96%and LT₅₀were 4.81 d,5.82 d respectively,.After inoculation with M.anisopliae Ma Wys-01,the corrected mortality rates of surface-treated S.invicta were significant higher than untreated with 100%,38.78%respectively,and LT₅₀were 3.99 d,4.54 d.It was indicate that the surface-microorganisms of S.invicta had significant inhibitory effects on the pathogenicity of B.bassiana and M.anisopliae to S.invicta.2)95 strains were isolated from surface of S.invicta,included 39 bacterial strains,33 actinomycetes strains and 23 fungi strains.By morphological and molecular identifying,the fungi were belong to a phylum:Eumycophyta,and the dominant genera was Aspergillus,the other were Lentinus,Mucor,Periconia,and Talamomyces.The bacteria were belong to three phylum:Proteobacteria,Firmicutes and Bacteroidetes,the dominant genera was Bacillus,the other were Bordetella,Pseudochrobactrum,Acinetobacter,Achromobacter,Rhizobium,Bacillus,Chryseobacterium,Staphylococus,Brevibacillus and Comamonas.The actinomycetes was belong to a phylum:Actinobacteria,the dominant genera was Streptomyces,also had Nonomuraea,Arthrobacter,Micrococcus,etc.3)The antagonistic activity of S.invicta surface-microorganisms against the B.bassiana BSX-PC and M.anisopliae Ma Wys-01 were determined by the confrontation growth.The results showed that 95 strains had different inhibitory activities on the two pathogenic fungi.Among them,11 fungal strains,15 bacterial strains and 19 actinomycete strains had stronger inhibition on B.bassiana BSX-PC,the bacteriostatic circle of 4 fungal strains,1 bacterial strain and 5 actinomycete strains to BSX-PC were more than 25 mm.Among the 95 strains,15 fungal strains,11bacterial strains and 5 actinomycetes had strong inhibitory effect on M.anisopliae Ma Wys-01.The bacteriostatic circle of 2 fungi strains to Ma Wys-01 were more than25 mm,but bacteriostatic circles of bacteria and actinomycetes to Ma Wys-01 were less than 25 mm.4)The germination of conidia is key to entomophytic fungi infect host insects.The effect of fermentation liquid on the spore germination rate of B.bassiana and M.anisopliae were determined with each 6 stronger inhibition strains of fungi,bacteria and actinomycetes.The results showed that the fermentation liquid of fungi 3Z-06,Z-08,Z-12,bacteria X-11,2X-02,X-26/728,actinomycetes 3F-01,3F-02,3F-03,3F-05,3F-06 had significant inhibitory effect on the spore germination of B.bassiana BSX-PC,the spore germination rates were only 16.69%,19.33%,23.32%,29.12%,30.30%,35.36%,52.12%,54.36%,55.43%,48.12%and 60.39%,respectively,those were lower significantly than control with 79.24%.the fermentation liquid of fungi Z-08,Z-16,bacteria X-11,actinomycetes 3F-03,3F-01,3F-04,3F-02 had significant inhibitory effect on the spore germination of M.anisopliae Ma Wys-01,the spore germination rates were only 33.63%,37.52%,32.09%,16.36%,20.36%,23.15%and 27.66%,respectively,those were significantly lower thanthe control with.73.42%.And fungi Z-08,3Z-06,Z-12,bacteria 2X-02,X-26/728,X-11,actinomycetes 3F-03,3F-05,3F-02,3F-01,3F-06 also had extremely significant inhibitory effects on the colony growth and sporulation quantity of B.bassiana BSX-PC.The fungi Z-08,Z-16,Z-04,Z-12,bacteria X-11,X-15,actinomycetes3F-03,3F-01,3F-04,3F-02 also had extremely significant inhibitory effects on the colony growth and sporulation quantity of M.anisopliae Ma Wys-01.It was indicate that S.invicta surface-microorganisms could inhibit fungi spore germination,it would avoiding or reducing the probability which S.invicta was infected by pathogens fungi.