Sex life of Aspergillus fumigatus is revealed

Submitted by Aspergillus Administrator on 2 December 2008

The discovery of a sexual cycle in the pathogenic fungus Aspergillus fumigatus has just been described in Nature by Scientists from The University of Nottingham and University College Dublin. Aspergillus fumigatus is an opportunistic human pathogen in individuals with weakened immune systems, causing potentially lethal invasive infections and is also associated with severe asthma and sinusitis.

First described 145 years ago this killer fungus, previously had no known sexual cycle and was only thought to reproduce by the production of asexual spores. Dr Paul Dyer (from Nottingham University) is an expert in the sexual development and population variation of fungi said “This discovery is significant – providing both good and bad news. The bad news is that we now know that Aspergillus fumigatus can reproduce sexually, meaning that it is more likely to become resistant to antifungal drugs in a shorter period, and the sexual spores are better at surviving harsh environmental conditions. The good news is that we can use the newly discovered sexual cycle as a valuable tool in laboratory experiments to try to work out how the fungus causes disease and triggers asthmatic reactions. Once we understand the genetic basis of disease we can then look forward to devising methods to control and overcome the fungus.”

The discovery of a sexual cycle in A. fumigatus provides insights into the biology and evolution of the species. It helps explain the presence of diverse genotypes despite predominantly clonal reproduction, the conservation of sex-related genes, aspects of genome evolution and defence against repetitive elements. In addition, production of ascospores might aid survival in adverse environmental conditions. The discovery has significant medical implications. Sexual reproduction can result in progeny with increased virulence or resistance to antifungal agents, and can confound diagnostic tests based on the assumption of clonality.

It is hoped the results of this research will lead to new ways of controlling this deadly disease and improved treatments for patients infected with it.
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