Confirmation of identification of a population of Aspergillus fumigatus isolates using a polyphasic approach

Celine O'Gorman1, Hubert Fuller1, Paul Dyer2

Author address: 

1UCD School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland, 2School of Biology, University of Nottingham, Nottingham, NG7 2RD, United Kingdom


A collection of 94 Aspergillus fumigatus sensu lato isolates was cultured from air samples taken at four outdoor locations during 2005 [1]. A polyphasic approach was employed for the identification of the isolates, using morphological, physiological and molecular data. Phenotypic characters were examined using established protocols [2] and included the macro- and micromorphology of the isolates, their maximal and minimal growth temperatures and their 25 °C/45 °C growth ratio. Results confirmed that all 94 isolates were A. fumigatus sensu stricto. Genotypic variation within the population was analysed by RAPD-PCR which revealed that the isolates are closely related but not identical. The distribution of the two complementary mating-type genotypes of the fungus (termed MAT1-1 and MAT1-2) was then determined using a multiplex mating-type PCR assay [3]. The population consisted of equal proportions of the MAT1-1 and MAT1-2 genotypes (49.4% MAT1-1, 50.6% MAT1-2), with no geographical clustering of mating-types evident. A representative sub-sample of 12 isolates from the population was chosen for further examination by multi-locus sequence typing of partial íŸ-tubulin and carboxypeptidase gene sequences. Phylogenetic analysis clearly grouped the 12 representative isolates with known Aspergillus fumigatus sensu stricto isolates. The results show that A. fumigatus isolates of complementary mating-type can be readily found in close proximity in nature, consistent with a sexually reproducing species.

abstract No: 


Full conference title: 

    • ECFG 9th (2008)