Enhanced diversity and aflatoxigenicity in interspecific hybrids of Aspergillus flavus and Aspergillus parasiticus
ABSTRACT: Aspergillus flavus and A. parasiticus are two of the most important aflatoxin-producing species that contaminate 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 out of forty-five attempted interspecific crosses between compatible mating types of A. flavus and A. parasiticus were fertile and produced viable ascospores. Single ascospore strains from each cross were isolated and 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 putative 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 species. Overall design: aCGH comparison between 3 strains of Aspergillus: 2 parental of either A. flavus (PF) and A. parasiticus (PP) and 1 progeny (F1) analyzed at the probe level. A total of six trio comparisons were made from a total of 56 isolates analyzed by aCGH. Trio comparisons are as follows: IC278 (PF), IC327 (PP) and IC1603 (F1); IC278 (PF), IC65 (PP) and IC1612 (F1); IC278 (PF), IC65 (PP) and IC1616 (F1); IC278 (PF), IC324 (PP) and IC1622 (F1); IC278 (PF), IC324 (PP) and IC1630 (F1); and finally IC278 (PF), IC33 (PP) and IC1637 (F1).
INSTRUMENT(S): [Flavus_22683_AFLAVUSa520391F] NCSU Payne_Aspergillus Array
SUBMITTER: Ignazio Carbone
PROVIDER: GSE61981 | GEO | 2015-10-01
SECONDARY ACCESSION(S): PRJNA262861