Evolution of Cytb, rDNA & morphology of Aspergillus section Nigri

Yokoyama K., Kagami K., Wang L., Takahashi H.

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Aspergillus section Nigri is included in very important species because they are used in fermentation industries and they also are encountered as human and plant pathogens and produced mycotoxins. The concept of black aspergilli has been classified as the Aspergillus niger group by Raper and Fennel and Aspergillus section Nigri by Games et al. In the past, the identification, classification and taxonomy of this group had mainly been based on morphological characteristics. D1/D2 region of ribosomal DNA was broadly used for identification of fungi and other organisms. However, it did not sufficient for identification of species on fungi. The observation of conidiospore surface by scanning electromicroscope (SEM) is useful methods for identification of section Nigri. The typical morphology of conidiospore surface of strain is ease however, some strains show intermediated morphology. Although some of tbe species can be readily distinguished morphologically, results obtained in several attempts at classifying this section are debatable and identification of some species is still difficult. The partial mitochondrial cytochrome b gene (Cyt b) was analyzed for identification, classification and phylogeny of pathogenic fungi by L. Wang et aI., S.K. Biswass et al. and K. Yokoyama et al.. DNA type of section Nigri were divided to 14 types and amino acid type were divided to 5 types. A. japonicus were divided into 4 DNA type, include in A. aculeatus. A. niger were divided into 4 DNA type. We compared among D1/D2, Cyt b and SEM, The results of SEM observations show continuous variation of conidiospore surface. Phylogenetic tree of D1/D2 and Cyto b sequences were difference. These were different evolution of nucleus, cytoscopic and total genetic expression (morphology). We discuss how to evolve the morphology, cytoplasmic inheritance and nuclear gene.

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17th International Society for Human and Animal Mycology
    • ISHAM 17th (2009)