Aspergillus parasiticus
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ABSTRACT:
PROVIDER: PRJNA1189688 | ENA |
REPOSITORIES: ENA
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Project description: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.
2015-10-01 | GSE61981 | GEO
Project description:Aflatoxins are toxic and carcinogenic secondary metabolites produced by the fungi Aspergillus flavus and A. parasiticus. In order to better understand the molecular mechanisms that regulate aflatoxin production, the biosynthesis of the toxin in A. flavus and A. parasticus grown in yeast extract sucrose media supplemented with 50 mM tryptophan (Trp) were examined. A. flavus grown in the presence of 50 mM tryptophan was found to have significantly reduced aflatoxin B1 and B2 biosynthesis, while A. parasiticus cultures had significantly increased B1 and G1 biosynthesis. Microarray analysis of RNA extracted from fungi grown under these conditions revealed seventy seven genes that are expressed significantly different between A. flavus and A. parasiticus, including the aflatoxin biosynthetic genes aflD (nor-1), aflE (norA), and aflO (omtB). It is clear that the regulatory mechanisms of aflatoxin biosynthesis in response to Trp in A. flavus and A. parasiticus are different. These candidate genes may serve as regulatory factors of aflatoxin biosynthesis. Keywords: Aflatoxin, Aspergillus, flavus, Amnio Acids, Tryptophan
2007-06-07 | GSE6182 | GEO
Project description:Aspergillus parasiticus Genome sequencing and assembly
| PRJNA994305 | ENA
Project description:Aspergillus parasiticus strain:PWE36 Genome sequencing
| PRJNA575261 | ENA
Project description:Aspergillus parasiticus FRR 5191 Genome sequencing
| PRJNA230216 | ENA
Project description:Aspergillus parasiticus FRR 3282 Genome sequencing
| PRJNA230222 | ENA
Project description:Aspergillus parasiticus FRR 2744 Genome sequencing
| PRJNA230220 | ENA
Project description:Aflatoxins are carcinogenic secondary metabolites produced by the fungi Aspergillus flavus and Aspergillus parasiticus. Repeated serial mycelial transfer or treatment of A. parasiticus with 5-azacytidine produced mutants with a fluffy phenotype and loss of aflatoxin production. To understand how these treatments affect aflatoxin production and development, we carried out expressed sequence tag (EST)-based microarray assays to identify differentially expressed genes in clones obtained from these treatments. Expression of 183 genes was significantly dysregulated. Of these, 38 had at least two-fold or lower expression compared to the untreated control and only two had two-fold or higher expression. The most frequent change was downregulation of genes predicted to be membrane-bound. Dysregulation of some of these may be responsible for the fluffy phenotype. Of the aflatoxin biosynthesis pathway genes only aflJ (aflS) was significantly affected by either treatment. A gene for a protein homologous to a key regulator of secondary metabolite biosynthesis (LaeA) was one of the upregulated genes and possibly could affect the activity of LaeA. Other genes known to be required for fungal developmental or aflatoxin production were not affected by the treatments. Consistent with the fluffy phenotype and the non-aflatoxigenicity of the clones obtained by either treatment, we hypothesize that the mutations cause improper development of conidiophores and specialized biosynthesis vacuoles (aflatoxisomes) needed for AF production. A. parasiticus wild-type (WT) and clones from serial mycelial transfer (SerTrans), and 5-azacytidine-treated (5-AC) fungi were grown for 16 and 24 h on PDA medium. RNA was isolated from the mycelia at each time point and cDNAs were labeled with Cy3 or Cy5 dyes prior to microarray assay.
2011-12-31 | E-GEOD-30756 | biostudies-arrayexpress
Project description:Aspergillus parasiticus SU-1 Genome sequencing and assembly
| PRJNA219623 | ENA