To find out the genetic variability in aflatoxin producing Aspergillus flavus strains of discolored rice in India.
Twenty-two aflatoxin B1 (AFB1) producing Aspergillus flavus strains were isolated from 1,200 discolored rice grain samples collected from 20 states across India and tested their potential to produce AFB1 on different agar media. Further these isolates were characterized through randomly amplified polymorphic DNA method.
All the strains of A. flavus produced AFB1 on yeast extract sucrose agar media, but none of the strains on A. flavus and A. parasiticus agar medium. Among the 22 strains, two strains from Tamil Nadu (DRAf 009) and Maharashtra (DRAf 015) produced high amount of AFB1 in all the media tested. To assess the genetic variability in A. flavus, the isolates were analyzed by using random amplified polymorphic DNA markers. The isolates showed 17–80% similarity with standard culture of A. flavus (MTCC 2799). In our study RAPD helped to confirm the identity of isolates as A. flavus.
In this paper we described the potential of AFB1 production by the strains of A. flavus and their genetic variability by RAPD-PCR. This is the first comprehensive report on the collection of large number of rice grain samples from across the country, isolation of different strains of A. flavus, identification of suitable media for maximizing AFB1 production and studies on genetic variability of A. flavus isolates by RAPD.