Ph.D. University of Melbourne, Australia
The fungal kingdom consists of an estimated 1.5-5 million species. Many of the best characterized species play either beneficial or detrimental roles in human endeavors: fungi are essential for life on earth and we interact with them on a daily basis. For example, fungi are used to produce or modify foods and drinks, the source of life-saving pharmaceuticals, recycle nutrients in the environment, and interact with the roots of more than 80% of land plants in a symbiotic relationship. On the other hand, fungi are the main agents of plant disease and rot wood, as well as causes of allergies and are common human infectious agents. A few species also cause life-threatening mycoses, especially in people with reduced immune function. Fungi are the most closely related group of organism to the animal kingdom. As such, they serve as models to understand both animal and eukaryote biology. For example, the concept that one gene encodes one protein was derived from Neurospora crassa (of note, those strains are housed next door in SBS in the Fungal Genetics Stock Center) and the genetics of cell cycle control (i.e. the underlying basis for all cancers) were elucidated through mutant studies in Saccharomyces cerevisiae and Schizosaccharomyces pombe.
Research in the laboratory is focused on how fungi sense their environment and transmit the signal to change physiology and development. We work on multiple and diverse species to address long-standing questions in fungal and eukaryotic biology using these organisms. The long-term goal is to develop strategies to reduce the adverse effects of fungi.
One research focus is how light is pereceived in fungi to alter the properties of pathogenic and other model fungi (i.e. Cryptococcus neoformans and Phycomyces blakesleeanus). Light has many effects on the way fungi grow. Often spore production is controlled by light, and since spores are one of the reasons for fungal success, understanding sensing and gene regulation by light is important to control fungi. Light is also linked to fungal virulence. Many fungi sense light, and in most of these species the machinery behind light sensing is the same, named White Collar 1 and 2 after the phenotypes of mutants originally isolated in N. crassa. The homologous genes control light-sensing in C. neoformans and P. blakesleeanus, which are distant relatives from N. crassa.
A second interest is on uncovering virulence mechanisms and potential drug targets in human pathogenic fungi, using C. neoformans. Fungi are some of the most common human infectious agents, particularly those that infect skin and nails, or cause yeast infections. Fungi also kill people, particularly if they have reduced immune functions due to a number of reasons. In the early 1980s, life-threatening fungal disease increased dramatically with the AIDS pandemic, and in countries without access to anti-viral and anti-fungal drugs, fungi are a major cause of mortality. C. neoformans is estimated to kill more than 600,000 people each year globally. Frustratingly, many of the cutting-edge developments in medicine, such as organ transplants, chemotherapy, or corticosteroid drugs, leave patients at high risk of fungal diseases. We use genetic screens to identify genes that the fungus has that are required for causing disease or essential for fungal viability. The proteins encoded by these genes are targets for rationale drug design, or at very least provide insight into why they are needed in fungi may provide practical measures to reduce fungal disease incidence.
Our third area of investigation explores the unique properties of several species of red yeast (subphylum Pucciniomycotina). These yeasts are common saprophytes in the environment. They represent a distinct group within the basidiomycetes that also includes the rust fungi that plague world agriculture. At present, very limited gene functional information is available from this group, in part because the rust species cannot be grown outside their plant hosts. Gaining gene information from the cultivable red yeasts is important for understanding, at a kingdom-wide level, the distribution of genes and their functions in fungi. We have recently developed the techniques and tools to transform red yeast species, and are now using these approaches to investigate gene functions in these fungi.
Our research uses a variety of experimental approaches. In addition to standard microbiology methods, we use molecular biology techniques, often coupled to forward genetic mutant screens, as well as classical Mendelian genetic crosses.
Magditch DA, Liu T-B, Xue C, Idnurm A. (2012) DNA mutations mediate microevolution between host-adapted forms of the pathogenic fungus Cryptococcus neoformans. PLoS Pathogens 8: e1002936. Article
Tagua VG, Medina HR, Martín-Domínguez R, Eslava AP, Corrochano LM, Cerdá-Olmedo E, Idnurm A. (2012) A gene for carotene cleavage required for pheromone biosynthesis and carotene regulation in the fungus Phycomyces blakesleeanus. Fungal Genet. Biol. 49: 398-404. Article
Idnurm A. (2011) Sex determination in the first-described sexual fungus. Eukaryot. Cell 10: 1485-1491. Article
Idnurm A. (2011) Sex and speciation: The paradox that non-recombining DNA promotes recombination. Fungal Biol. Rev. 25: 121-127. Article
Ianiri G, Wright SAI, Castoria R, Idnurm A. (2011) Development of resources for the analysis of gene function in Pucciniomycotina red yeasts. Fungal Genet. Biol. 48: 685-695. Article