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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Food and Feed Safety Research » Research » Publications at this Location » Publication #397520

Research Project: Aflatoxin Control through Identification of Intrinsic and Extrinsic Factors Governing the Aspergillus Flavus-Corn Interaction

Location: Food and Feed Safety Research

Title: Genomic and metabolomic diversity within a familial population of Aspergillus flavus

item Moore, Geromy
item Mack, Brian
item WENDT, KAREN - University Of Oklahoma
item Castano-Duque, Lina
item ANDERSON, VICTORIA - University Of Oklahoma
item CICHEWICZ, II, ROBERT - University Of Oklahoma

Submitted to: Molecular Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: It is not well known what happens at the genome level when two A. flavus strains mate. A previous study paired a strain that produces aflatoxin with a biocontrol strain had been engineered to fluoresce green when exposed to long-wave ultraviolet light. Ten offspring were isolated... five of them were fluorescent, and the other five were non-fluorescent. In this study, we sequenced the genomes of these 12 A. flavus strains to look for evidence of genetic shuffling, trait inheritance, and changes in metabolite production among the offspring. We found that all the fluorescent, and one non-fluorescent, offspring were genetically identical to the biocontrol parent. Despite being genetically identical, there were metabolites and traits that were not identical. The other four non-fluorescent offspring were recombinants, having experienced genome shuffling and containing different segments of DNA from both parents. Only one of the non-fluorescent offspring inherited aflatoxin production. We showed that recombination does not occur in the same place in any given genome and that a substantial amount of recombination and diversity can arise in a single generation. This has possible implications for the release of fertile biocontrol strains into agricultural fields where recombination can occur.

Technical Abstract: This study involved preliminary investigations into inheritance of the mating type gene and vegetative compatibility group (VCG) testing. All 10 progenies (F1s) had inherited the MAT1-2 gene from the biocontrol parent (1587G). Six of the F1s (all the fluorescent F1s and one non-fluorescent F1) shared a VCG with 1587G, and the remaining non-fluorescent F1s were unique VCGs. Upon examination and comparison of the sequenced genomes of our F1s, all five of the fluorescent progenies (F1s) shared genomic identity with the biocontrol parent (1587G), with the exception of point mutations that were unique to each F1 and not inherited from either parent. These random mutations may have contributed to the observed differences in global metabolite production for these F1s that experienced uniparental inheritance. The one non-fluorescent F1 sharing a VCG with 1587G and its fluorescent siblings had inherited the complete eGFP construct despite not exhibiting noticeable fluorescence. Among the remaining four non-fluorescent F1s that represented unique VCGs, two had also inherited the complete eGFP construct although both had high numbers of mutations in the promoter/terminator regions around the eGFP gene, which likely caused their inabilities to fluorescence. Recombination breakpoints ranged in quantity from 17-29 across these four VCGs, and hotspots were observed that were shared among these F1s. Only one of them had inherited the ability to produce aflatoxin and cyclopiazonic acid.