Mitochondrial DNA restriction fragment length polymorphisms in field isolates of the Aspergillus niger aggregate

Abstract

The mitochondrial DNAs (mtDNAs) and the ribosomal repeat unit (ribosomal DNA, rDNA) of black Aspergillus isolates collected in various parts of the world were examined. Wide-ranging mtDNA variation was observed in natural populations of the Aspergillus niger aggregate. Most isolates were classifiable as A. niger or Aspergillus tubingensis according to their rDNA and mtDNA patterns. The mtDNA variation was distributed unevenly in the populations studied. The mtDNAs of most of the isolates collected in Australia were of the A. tubingensis type, with an unexpectedly high degree of variation, while the rDNA of these isolates exhibited the same A. tubingensis pattern as that of isolates from other locations. Some other local populations displayed very little polymorphism in their mtDNA and rDNA. Hybridization experiments in which cloned A. niger and Aspergillus nidulans mtDNA fragments were used revealed that the two main mtDNA groups corresponding to A. niger and A. tubingensis are more distantly related than concluded earlier. Six of the 13 Brazilian isolates examined exhibited mtDNA and rDNA types different from those of all the other strains and could not be classified into the above species. Classical taxonomic examination of these strains is in progress.

AspergillusEnzymes Involved in Degradation of Plant Cell Wall Polysaccharides

“…Some of these groups consist of pathogenic fungi (e.g., A. fumigatus, A. flavus, and A. parasiticus), but most important for industrial applications are some members of the group of black aspergilli (A. niger and A. tubingensis). In addition to the morphological techniques traditionally applied, new molecular and biochemical techniques have been used in the reclassification of this group of aspergilli (137,226,257,271,283,386 (283). Products of several of these species have obtained a GRAS (Generally Regarded As Safe) status, which allows them to be used in food and feed applications.…”

Efficient degradation of tannic acid by black Aspergillus species

“…Isopropanol was used to precipitate the nucleic acids, they were washed with 70 % ethanol and finally resupended in demi water or TE buffer (10 mM Tris/ 10 mM EDTA, pH 7.5). Restriction enzyme analyses were performed with both BglII and HaeIII for A. niger, A. tubingensis and A.brasiliensis haplotypes (Varga et al 1993(Varga et al , 1994 and with HaeIII or EcoRI for A. japonicus and relatives (Hamari et al 1997) and A. carbonarius and relatives (Kevei et al 1996).…”

“…b A. niger mitochondrial RFLP haplotypes 1a-1d and A. tubingensis haplotypes 2a-2f as recognised by Varga et al (1993Varga et al ( , 1994. c jap, A. japonicus and direct relatives (Hamari et al 1997).…”

Aspergillus uvarum sp. nov., an uniseriate black Aspergillus species isolated from grapes in Europe

“…Black aspergilli are one of the more difficult groups to classify and identify and the taxonomy of Aspergillus section Nigri has been studied by many taxonomists (Abarca et al, 2004;Varga et al, 2007). Nuclear and mitochondrial DNA (mtDNA) polymorphisms and PCR-based techniques led to the recognition of at least two species within the A. niger species complex (A. niger and Aspergillus tubingensis) (Kusters-van Someren et al, 1991;Varga et al, 1994). Phylogenetic analyses of sequences of the internal transcribed spacers region (ITS), the 5.8S rRNA gene and the D1-D2 region of the 28S rRNA gene indicated that, in addition to A. niger and A. tubingensis, at least five other species belong to section Nigri: Aspergillus heteromorphus, Aspergillus ellipticus, Aspergillus carbonarius, Aspergillus japonicus and Aspergillus aculeatus (Varga et al, 2000;Parenicova et al, 2001).…”