Genomic and metabolomic variability within a familial population of Aspergillus flavus

Aspergillus flavus is an agriculturally significant micro-fungus that has the potential to contaminate food and feed crops with toxic secondary metabolites such as aflatoxin and cyclopiazonic acid. Research has shown that A. flavus is capable of overcoming heterokaryon incompatibility to undergo meiotic recombination as teleomorphs. Although evidence of recombination in the aflatoxin gene cluster has been reported, impacts at both the genomic and metabolomic levels of recombination in a single generation have not been reported. Previously, this lab paired an aflatoxigenic MAT1-1 A. flavus strain with a non-aflatoxigenic MAT1-2 A. flavus strain that had been tagged with green fluorescent protein, and then 10 F1 progenies (a mix of fluorescent and non-fluorescent) were randomly selected from single-ascospore colonies and broadly examined for evidence of recombination. We found four of the F1 progenies to be wholly recombinant since they were not vegetatively compatible with either parent or their siblings, and they exhibited other distinctive traits that were the result of recombination. The other six progenies examined were very similarnearly identical to the non-aflatoxigenic, fluorescent, and MAT1-2 parent. This study highlights the potential genomic changes that can occur in a single generation from the out-crossing of sexually compatible strains of A. flavus.