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In Vitro Antagonistic Activity of Diverse Bacillus Species Against Fusarium culmorum and F. solani Pathogens
Abstract
Background:
Fusarium culmorum and Fusarium solani are economically important fungal pathogens of many plant species causing significant yield losses worldwide. Frequent uses of fungicides are hazardous to humans and the environment. Therefore, in vitro antagonistic activity of diverse Bacillus species isolates with biological potential activity to control these both pathogens should be investigated.
Objective:
The objectives were to isolate and identify the Bacillus spp., which are potential controls of F. culmorum and F. solani, and to characterize molecularly, at the species level, those isolates that have potential as biocontroller of the pathogens.
Methods:
The in vitro antagonistic potential of 40 Bacillus isolates against F. culmorum and F. solani was evaluated on the basis of fungal growth inhibition on nutrient broth culture. The colony morphology and the 16S rRNA gene sequencing of Bacillus spp. were used to identify the isolates.
Results:
Bacillus sp. isolates were identified as B. atrophaeus, B. subtilis, Paenibacillus polymxa, B. amyloliquefaciens, B. simplex and B. tequilensis. They had significant (P<0.05) antagonistic activities against F. culmorum and F. solani isolates as compared to the untreated control. The antagonistic effects varied depending on the Fusarium sp. The bacterial B. subtilis isolates SY116C and SY SY118C provided the most noteworthy result as both strongly inhibited mycelial growth of F. solani by 97.2%, while the B. tequilensis isolate SY145D was the most effective in the formation of inhibition zones against F. culmorum by 75%.
Conclusion:
It is apparent that Bacillus sp. isolates play an important role in the inhibition of growth of F. culmorum and F. solani, and that the B. subtilis isolates SY116C and SY118C had the highest biological potential activity against these fungi. These antagonistic effects may be important contributors as a biocontrol approach that could be employed as a part of integrated soil pathogen management system.
