detection of aflatoxin b1-producing aspergillus flavus strains from pistachio orchards soil in iran by multiplex polymerase chain reaction method

Background and purpose: the current study aimed to report a multiplex polymerase chain reaction (pcr) assay as a monitoring technique to differentiate aflatoxigenic from non-aflatoxigenic strains of aspergillus flavus isolated from pistachio orchards soil.materials and methods: in total, 25 a. flavus strains were isolated from soil samples of pistachio orchards. to test the strains for aflatoxin b1(afb1)-producing ability, thin-layer chromatography (tlc) was used and the amounts of afb1 were measured by high performance liquid chromatography (hplc). multiplex pcr was used as a genome-based method to detect genes responsible for afb1 production by a. flavus and the results were analyzed in terms of speed and specificity of detection. a set of four primers was designed specifically for the omta, omtb, ver-1, and aflr genes which are commonly present in aflatoxin biosynthetic pathways.results: the afb1 production by the a. flavus strains ranged from 0 to 321 ρg/μl. four band patterns of the primer sets were observed only in afb1-producing a. flavus strains. moreover, 18 out of the 25 strains showed all four bands belonging to omta, omtb, ver-1, and aflr, whereas 7 strains did not display omta, or aflr-related bands, in non-toxigenic and low toxin-producing a. flavus.conclusion: the multiplex pcr is a supplementary strategy to current conventional mycotoxin analytical techniques, such as tlc and hplc. it could be used as an efficient method to differentiate aflatoxigenic from non-aflatoxigenic strains of a. flavus. this achievement is crucial to minimize fungal contamination of food, feed, and agricultural commodities, thereby reducing the risk of subsequent aflatoxin consumption.