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ARS Home » Southeast Area » Dawson, Georgia » National Peanut Research Laboratory » Research » Publications at this Location » Publication #379913
Research Project: Integrated Management of Fungal Pathogens in Peanut to Reduce Mycotoxin Contamination and Yield Losses

Location: National Peanut Research Laboratory

Title: Genetic map and heritability of Aspergillus flavus

Author
item GELL, RICHARD - North Carolina State University
item HORN, BRUCE - Former ARS Employee
item CARBONE, IGNAZIO - North Carolina State University

Submitted to: Fungal Genetics and Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/7/2020
Publication Date: 10/12/2020
Citation: Gell, R.M., Horn, B.W., Carbone, I. 2020. Genetic map and heritability of Aspergillus flavus. Fungal Genetics and Biology. (144):103478. https://doi.org/10.1016/j.fgb.2020.103478.
DOI: https://doi.org/10.1016/j.fgb.2020.103478

Interpretive Summary: The fungus Aspergillus (A.) flavus invades many agricultural commodities, especially corn, peanuts and tree nuts, and is responsible for enormous economic losses due to the production of carcinogenic aflatoxins. In populations of A. flavus, individuals are highly variable in aflatoxin production and much of this variation is due to sexual reproduction. The parents and their offspring from three matings were analyzed for their genetic composition, and the genetic changes due to sexual reproduction were identified. Such gene maps will be useful for optimizing biological control using nonaflatoxin-producing strains of A. flavus.

Technical Abstract: The carcinogenic aflatoxins are a human health concern as well as an economic burden to corn, peanut and other crops grown within the United States and globally. Aflatoxins are produced by fungi species in Aspergillus (A.) section Flavi, primarily Aspergillus flavus. Though previously thought of as only asexual, A. flavus has recently been found to undergo sexual reproduction both in laboratory crosses and in the field. To elucidate the consequences of genetic exchange through a single generation of the sexual cycle within A. flavus, we constructed genetic maps based on three mapping populations, each composed of the parental strains and approximately 70 F1 progeny. Genome-wide data using double digest Restriction Associated DNA sequencing identified 496, 811, and 576 significant polymorphisms differentiating parents across eight linkage groups; these polymorphisms served as markers. Average spacing between marker loci was 3.1, 2.1, and 3.5 map units and overall map length was 1504.4, 1669.2, and 2001.3 cM. Recombination was non-randomly distributed across chromosomes with an average rate of recombination of about 46.81 cM per Mbp. We showed inheritance of mitochondrial loci from the sclerotial (female) parent in crosses, whereas nuclear loci showed a 1:1 segregation ratio from both parents. The linkage map will be useful in QTL analyses to identify traits that increase sexual fertility in A. flavus and modulate aflatoxin production, both of which have significant implications for sustainable reduction of aflatoxin contamination using biological control agents.