The fastest and smuttiest CRC PhD project…

VANMEURSA — Mon, 20 Dec 2010 01:00:56 +0000

Alistair McTaggart, of Queensland’s Department of Employment, Economic Development and Innovation, has just completed his CRC PhD project through Queensland University of Technology. In landmark work, he has completely revised the taxonomy of three large genera of smut fungi, Ustilago, Sporisorium and Macalpinomyces. This project has important biosecurity implications as this group of fungi includes many economically important pathogens such as Ustilago maydis (boil smut of maize) and Sporisorium scitamineum (sugarcane smut).

While working on a PhD is complex and certainly not a race, at this stage, Alistair will have submitted his thesis in record time. He started his PhD on 1 January 2008 (hats off to him for starting on a public holiday), had his final seminar on 2 December 2010 and says he will be submitting his thesis for examination on 24 December 2010 (just in time to relax and enjoy Christmas). This makes his whole PhD project a total of two years, 11 months and 24 days to complete.

Alistair says he attributes this to having a well designed project with a lot of support from his supervisors and also from the CRC in terms of professional development and the opportunity to travel and enhance his research outcomes.

In an effort to continue to expand his knowledge in this area, he has already secured a post-doctoral position at Louisiana State University to work on the systematics of rust fungi and to construct a rust database. With his US visa sorted out, he’s looking to head over in early 2011, where Alistair says he is “looking forward to learning something new, buying a few guitars, listening to blues music, meeting some Southern women, eating some gumbo and rockin' plant pathology.”

Alistair also says he is a little sad to finish because “he’ll never get to work on something like that again”, which could leave readers with the question of what was his project about?

Once called the ‘insidious black harvest’, smut fungi infect commercially important plants such as wheat, and grasses more generally, to produce vast amounts of fine black spores. In addition to food security threats, the mere presence of spores in a shipment of grain can – and has – posed threats to Australia’s export trade.

While smut fungi are very host-specific – infecting a narrow range of grasses – the spores from different species tend to look the same under the microscope. That makes diagnostics difficult to all but the most accomplished mycologists.

Alistair says smuts form a huge taxonomic group containing more than 500 species. The morphological features used to classify smuts can create confusion, he says, and the current classification does not accommodate the vast diversity of smut species discovered over the years.

“It is my job to try and resolve this taxonomic muddle by finding natural groups for these smut fungi,” he says. “To detect the natural groupings we have been studying morphology and using DNA sequence data to trace relationships based on similarities and divergences that occurred during evolution.”

Of particular interest is a region of the smut genome that encodes ribosomal RNA – molecules required by the cell to make proteins. In this region is the so-called ITS (the internal transcribed spacer), a stretch of DNA that has been proposed as the ‘barcode’ for all fungal organisms.
Parts of the ITS are known to change rapidly during evolution since they do not encode anything vital for fungal survival. These regions eventually become idiosyncratic among fungi. But the ITS also contains sequences that are conserved among closely related smuts. This is useful for identifying groups or genera in phylogenetics studies.

Since the ITS can distinguish both groups and species, Alistair has sequenced the ITS region of all 80 smuts in his collections. “In my groupings, you can see smuts co-evolving with grasses at the tribe and sub-tribe taxonomic levels,” he says. “So smuts of cereals like wheat, oats, and barley that are closely related also have similar morphological characters. Smuts that occur on outback Spinifex grasses similarly form a closely related group.”

The CRC wish Alistair the best of luck during the thesis examination process and look forward to him returning to Australia with valuable training in how to identify exotic rusts, and to help keep Australia safe from the nasties!

Photo caption: Alistair McTaggart accepts his award for Best Student Poster at the 2009 Science Exchange.

Photo acknowledgement: Di Harris Photographic

CRC60074: Smut Fungi - PhD

K.Scott — Wed, 06 Aug 2008 01:00:24 +0000

CRC for Plant Biosecurity - smut

The fastest and smuttiest CRC PhD project…

CRC60074: Smut Fungi - PhD