Data from: Enhanced diversity and aflatoxigenicity in interspecific hybrids of Aspergillus flavus and Aspergillus parasiticus

Aspergillus flavus and A. parasiticus are the two most important
aflatoxin-producing fungi responsible for the contamination of
agricultural commodities worldwide. Both species are heterothallic and
undergo sexual reproduction in laboratory crosses. Here we examine the
possibility of interspecific matings between A. flavus and A. parasiticus.
These species can be distinguished morphologically and genetically, as
well as by their mycotoxin profiles. Aspergillus flavus produces both B
aflatoxins and cyclopiazonic acid (CPA), B aflatoxins or CPA alone, or
neither mycotoxin; Aspergillus parasiticus produces B and G aflatoxins or
the aflatoxin precursor O-methylsterigmatocystin, but not CPA. Only four
of forty-five attempted interspecific crosses between opposite mating
types of A. flavus and A. parasiticus were fertile and produced viable
ascospores. Single ascospore strains from each cross were shown to be
recombinant hybrids using multilocus genotyping and array comparative
genome hybridization. Conidia of parents and their hybrid progeny were
haploid and predominantly monokaryons and dikaryons based on flow
cytometry. Multilocus phylogenetic inference showed that experimental
hybrid progeny were grouped with naturally occurring A. flavus L strain
and A. parasiticus. Higher total aflatoxin concentrations in some F1
progeny strains compared to midpoint parent aflatoxin levels indicate
synergism in aflatoxin production; moreover, three progeny strains
synthesized G aflatoxins that were not produced by the parents, and there
was evidence of allopolyploidization in one strain. These results suggest
that hybridization is an important diversifying force resulting in the
genesis of novel toxin profiles in these agriculturally important fungi.