An Overview of the Genus Aspergillus

Aspergillus is the name used for a genus of moulds that reproduce only by asexual means. The morphology of the conidiophore, the structure that bears asexual spores, is the most important taxonomic character used in Aspergillus taxonomy. Aspergillus species are common and widespread. They are among the most successful groups of moulds with important roles in natural ecosystems and the human economy. Among scientists working on Aspergillus, there is a continuing fascination with their biotechnological potential. In addition to producing numerous useful extracellular enzymes and organic acids, these moulds also produce secondary metabolites of importance in biotechnology. Some Aspergillus species function as plant and/or animal pathogens. Aspergillosis is the name given to all animal diseases caused by growth of any member of the genus on a living host. Immunosuppression is generally a prerequisite for systemic Aspergillus infections in humans. The incidence of systemic aspergillosis, the most serious form, is on the rise and imposes an increasing medical burden upon hospitals and physicians. Better antifungal drugs and diagnostic methods are needed. Advances in Aspergillus genomics are giving us new tools for understanding this extremely diverse genus. Hitherto undiscovered sexual stages have been discovered based on findings from genomics. Molecular biologists are trying to understand the mechanisms by which pathogenicity and sexuality work and to deconstruct the physiological pathways that are central to these processes. Evolutionary biologists are focusing on the forces that drive variation within and among population. Economically important species are being re-tested for new capabilities using new screens developed with the aid of post genomic technologies.