Investigation of antagonistic potential bacterial isolates from pistachio orchards in Yazd Province against aflatoxin-producing Aspergillus flavus

Bacteria are able to synthesis a wide range of metabolites with fungicidal and bacterial capabilities. In this study antagonist bacteria were isolated from 8 soil samples of Pistachio orchards in Yazd, Iran. Eight isolated bacteria were phenotypically and genotypically identified as Bacillus spp. Also Aspergillus flavus were isolated from samples were collected from Pistachio orchards in Yazd, Iran. Aspergillus flavus species were identified by macroscopic and microscopic characteristics among the isolated fungi. Then aflatoxin production was determined by HPLC method. Antifungal activity of bacterial strains (Pr1 to Pr9) against Aspergillus flavus was determinate by agar diffusion technique. Results showed that all tested bacterial species show varying degree of biocontrol potential against Aspergillus flavus. Also results showed that Pr7 isolate was effective biocontrol against Aspergillus flavus with reduction of 797 in fungal colony diameter. While Pr4 isolate showed the lowest biocontrol against Aspergillus flavus with reduction of 667 in fungal colony diameter. The presented data exhibit the antifungal activity of bacterial species and indicate the possibility of using these bacterial species as biological agent to control Aspergillus flavus.

Keywords:

Antagonistic , Aspergillus flavus , Biocontrol , Bacillus