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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetics, Populations Dynamics, and Mycotoxin Prevention in Peanut

Location: Peanut Research

Title: Sexual reproduction in Aspergillus tubingensis from section Nigri

item Horn, Bruce
item Olarte, Rodrigo
item Peterson, Stephen - Steve
item Carbone, Ignazio

Submitted to: Mycologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2013
Publication Date: 5/24/2013
Publication URL: http://doi:10.3852/13-101
Citation: Horn, B.W., Olarte, R.A., Peterson, S.W., Carbone, I. 2013. Sexual reproduction in Aspergillus tubingensis from section Nigri. Mycologia 105(5): 1153-1163.

Interpretive Summary: Aspergillus niger and A. tubingensis are of great economic importance due to their invasion of crops, production of mycotoxins and deterioration of stored foodstuffs. These fungi are also used extensively in industry for the production of enzymes and organic acids. In this research, A. tubingensis strains of the opposite mating type were crossed and sexual reproduction was shown for the first time. Sexual reproduction may be useful for enhancing enzyme and organic acid production in industrial strains of A. tubingensis.

Technical Abstract: A sclerotium-forming member of Aspergillus section Nigri was sampled from a population in a single field in North Carolina, USA, and identified as A. tubingensis based on genealogical concordance analysis. Aspergillus tubingensis was shown to be heterothallic, with individual strains containing either a MAT1-1 or MAT1-2 mating-type gene. Strains of opposite mating type were crossed on mixed cereal agar and incubated for 5–6 months. Stromata typically formed 1–2 indehiscent ascocarps containing asci and ascospores within the pseudoparenchymatous matrix in a manner similar to the Petromyces sexual stage from section Flavi, which is closely related to section Nigri. Ascospores of A. tubingensis differed from those of section Flavi species in the reticulate ornamentation of ascospores and the presence of two crests that form an equatorial furrow. Sexual reproduction in A. tubingensis may be useful for enhancing enzyme and organic acid production through recombination-mediated genetic engineering of industrial strains.

Last Modified: 10/19/2017
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