Evolutionary Relationships Among Aspergillus terreus Isolates and their Relatives
Department of Microbiology, Faculty of Sciences, University of Szeged, P.O. Box 533, H-6701, Szeged, Hungary. Antonie van Leeuwenhoek
(Impact Factor: 1.81).
09/2005; 88(2):141-50. DOI: 10.1007/s10482-005-3870-6
Aspergillus terreus is a ubiquitous fungus in our environment. It is an opportunistic human pathogen and economically important as the main producer of lovastatin, a cholesterol lowering drug. Our aim was to examine the genetic variability of A. terreus and closely related species using molecular and analytical techniques. Lovastatin production was examined by HPLC. Lovastatin was produced by seven isolates belonging to the species A. terreus. RAPD analyses were carried out using 25 different random primers. Neighbor-joining analysis of RAPD data (120 characters) resulted in clustering of the A. terreus isolates into distinct groups. Some correlation was observed between lovastatin producing abilities of the isolates and their position on the dendrogram based on RAPD profiles. The internal transcribed spacer region and the 5.8S rRNA gene of A. terreus and related isolates was also sequenced. Phylogenetic analysis of sequence data let us classify the isolates into different clades which mostly correspond to the species Aspergillus terreus, Aspergillus flavipes, Aspergillus niveus, Aspergillus carneus and Aspergillus janus/A. janus var. brevis. Aspergillus allahabadii, A. terreus var. aureus and A. niveus var. indicus belonged to the A. niveus clade, while an Aspergillus isolate previously classified as A. niveus was most closely related to A. flavipes isolates. Aspergillus anthodesmis formed a distinct branch on the tree. Although it was previously suggested based on 28S rDNA sequence data that Aspergillus section Terrei should include A. carneus and A. niveus isolates, phylogenetic analysis of ITS sequences indicate that A. flavipes isolates are more closely related to A. terreus than A. carneus isolates. Our data suggest that sections Terrei and Flavipedes should be merged. However, further loci should be analysed to draw more definite conclusions.
Available from: Milton A Typas
- "This causes some concern because our dataset places A. arenarius as a sister clade to section Flavi with good support (bootstrap of 90% for NJ and 100% for MP analyses; 69% Posterior Probabilities for the BI analyses; Figure 6), contrary to suggestions that it is unrelated to any section of Aspergillus . Similarly, our concatenated analysis contradicts the proposed merger of sections Terrei and Flavipedes [24, 57] because A. janus is excluded from being a sister clade of section Terrei (Figure 6). Since the datasets from the other genetic loci, examined in this work, show a random positioning of A. janus and A. arenarius, it is obvious that a thorough molecular analysis of the relations between Terrei and Flavipedes is urgently needed, especially if previous members of Versicolores, like A. janus and A. arenarius, are to be included within these sections. "
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ABSTRACT: Aspergillus species originating from Greece were examined by morphological and molecular criteria to explore the diversity of this genus. The phylogenetic relationships of these species were determined using sequences from the ITS and IGS region of the nuclear rRNA gene complex, two nuclear genes ( β -tubulin (benA) and RNA polymerase II second largest subunit (rpb2)) and two mitochondrial genes (small rRNA subunit (rns) and cytochrome oxidase subunit I (cox1)) and, where available, related sequences from databases. The morphological characters of the anamorphs and teleomorphs, and the single gene phylogenetic trees, differentiated and placed the species examined in the well-supported sections of Aenei, Aspergillus, Bispori, Candidi, Circumdati, Clavati, Cremei, Flavi, Flavipedes, Fumigati, Nidulantes, Nigri, Restricti, Terrei, Usti, and Zonati, with few uncertainties. The combined use of the three commonly employed nuclear genes (benA, rpb2, and ITS), the IGS region, and two less often used mitochondrial gene sequences (rns and cox1) as a single unit resolved several taxonomic ambiguities. A phylogenetic tree was inferred using Neighbour-Joining, Maximum Parsimony, and Bayesian methods. The strains examined formed seven well-supported clades within the genus Aspergillus. Altogether, the concatenated nuclear and mitochondrial sequences offer additional tools for an improved understanding of phylogenetic relationships within this genus.
Available from: PubMed Central
- "Besides A. terreus and its varieties, section Terrei also includes A. niveus (teleomorph: Fennellia nivea), A. carneus, A. niveus var. indicus, A. allahabadii, A. ambiguus and A. microcysticus (Peterson 2000, 2008, Varga et al. 2005). The first three species have previously been placed in section Flavipedes and the last three species were placed in section Versicolores (Raper & Fennell 1965, Samson 1979). "
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ABSTRACT: Section Terrei of Aspergillus was studied using a polyphasic approach including sequence analysis of parts of the β-tubulin and calmodulin genes and the ITS region, macro- and micromorphological analyses and examination of extrolite profiles to describe three new species in this section. Based on phylogenetic analysis of calmodulin and β-tubulin sequences seven lineages were observed among isolates that have previously been treated as A. terreus and its subspecies by Raper & Fennell (1965) and others. Aspergillus alabamensis, A. terreus var. floccosus, A. terreus var. africanus, A. terreus var. aureus, A. hortai and A. terreus NRRL 4017 all represent distinct lineages from the A. terreus clade. Among them, A. terreus var. floccosus, A. terreus NRRL 4017 and A. terreus var. aureus could also be distinguished from A. terreus by using ITS sequence data. New names are proposed for A. terreus var. floccosus, A. terreus var. africanus, A. terreus var. aureus, while Aspergillus hortai is recognised at species level. Aspergillus terreus NRRL 4017 is described as the new species A. pseudoterreus. Also included in section Terrei are some species formerly placed in sections Flavipedes and Versicolores. A. clade including the type isolate of A. niveus (CBS 115.27) constitutes a lineage closely related to A. carneus. Fennellia nivea, the hypothesized teleomorph is not related to this clade. Aspergillus allahabadii, A. niveus var. indicus, and two species originally placed in section Versicolores, A. ambiguus and A. microcysticus, also form well-defined lineages on all trees. Species in Aspergillus section Terrei are producers of a diverse array of secondary metabolites. However, many of the species in the section produce different combinations of the following metabolites: acetylaranotin, asperphenamate, aspochalamins, aspulvinones, asteltoxin, asterric acid, asterriquinones, aszonalenins, atrovenetins, butyrolactones, citreoisocoumarins, citreoviridins, citrinins, decaturins, fulvic acid, geodins, gregatins, mevinolins, serantrypinone, terreic acid (only the precursor 3,6-dihydroxytoluquinone found), terreins, terrequinones, terretonins and territrems. The cholesterol-lowering agent mevinolin was found in A. terreus and A. neoafricanus only. The hepatotoxic extrolite citrinin was found in eight species: A. alabamensis, A. allahabadii, A. carneus, A. floccosus, A. hortai, A. neoindicus, A. niveus and A. pseudoterreus. The neurotoxic extrolite citreoviridin was found in five species: A. neoafricanus, A. aureoterreus, A. pseudoterreus, A. terreus and A. neoniveus. Territrems, tremorgenic extrolites, were found in some strains of A. alabamensis and A. terreus.
Available from: Narasimhan Banu
- "Several recent studies have clearly demonstrated that morphological methods are poor markers of species in the genus Aspergillus, and molecular methods may be useful in species identification  . Phylogenetic analyses of DNA sequences derived from ITS regions and showed the presence of three main clades, which included A. terreus, A. carneus and A. niveus within the section Terrei . However, that study concluded the section Terrei warranted further detailed molecular analysis including more loci and isolates. "
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ABSTRACT: RAPD was used to examine the genetic variability among five isolates of Aspergillus terreus spp. Two random primers were selected for the RAPD assay PG01–5' CAGGTGTTGC 3' and PG02–5' CTGGA-CAGAC 3' (Progen Technologies). The characteriza-tion of Aspergillus terreus species have been mostly applied on the basis of morphology, phenotype and physiology. DNA Polymorphisms are based on dif-ferences in DNA sequences and have advantages over protein polymorphisms. But morphological charac-terization besides molecular tools will remain a basic and powerful key in the identification of Aspergillus terreus species. The objective of the present study was to isolate the fungal contaminants from dried grapes and compare the genomic profile of the Aspergillus terreus speices isolated from the dried grapes, through RAPD analysis. In the present study with primer PG 01 four different discriminations was there among the A. terreus isolates. There was a ho-mology of genotype between the isolates 1 & 3. And with primer PG 02 four different discriminations were there and there was a homology between 1 & 3. The predominant type was type I in primer I & II. The other isolates belonged to 2, 3 and 4. No similar-ity was detected for isolates 3, 4 and 5 indicating great genomic diversity of A. terreus.
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