Identification, classification and phylogeny of the Aspergillus section Nigri inferred from mitochondrial cytochrome b gene.

The partial mitochondrial cytochrome b gene from 32 strains of 12 species belonging to Aspergillus section Nigri was amplified by the polymerase chain reaction and sequenced directly. Using 402 nucleotide characters, nucleotide-based and amino acid-based phylogenetic trees were inferred and the genetic divergence among the species was evaluated. Based on analyses of the 402-bp nucleotide and 133-amino acid sequences, strains were divided into 11 DNA types and five amino acid types. Aspergillus niger and Aspergillus awamori showed different amino acid sequences. A. niger clade included A. niger var. niger and Aspergillus ficuum. A. awamori clade included A. awamori, Aspergillus phoenicis, Aspergillus pulverulentus, Aspergillus tubingensis, Aspergillus foetidus, and two varieties of A. niger, var. nanus and var. intermedius. Two varieties of A. niger will be reclassified. One strain of A. phoenicis and one strain of Aspergillus carbonarius were reidentified.