THE UNLOCKING of the genetic sequence of a gene formerly used in breeding confer leaf rust in barley may save Australian farmers millions in avoiding lost production.
A University of Sydney scholarship student made the research breakthrough recently.
PhD student, Hoan Dinh defined the sequence of gene Rph 3, which was used for years in breeding to give varieties resistance against leaf rust before breaking down in the face of a new rust pathotype around 2009.
Agriculture Victoria said early infections of rust in barley crops could cause yield losses of up to 30 per cent.
Dr Dinh's supervisor, Robert Park, said understanding how the resistance gene meant researchers could see if it could be bundled with other genes to create a resistant variety or even resequenced to regain control over the disease.
Professor Park said Dr Dinh's work was likely to be a big benefit to Australian grain breeding down the track.
"Hoan undertook painstaking work over three years to isolate the gene from the barley genome, which is about the same size as the human genome," Professor Park said.
"He found that the Rph3 gene is a new class of resistance gene in plants generally, which has led our research in a new direction that we think will advance rust resistance," he said.
The results were so remarkable that Dr Dinh initially worried he had made a mistake.
"When I first found the gene, I was worried I had done something wrong because it was so unusual," Dr Dinh said.
"The majority of disease resistance genes belong to a different gene family. It felt great to be vindicated," he said.
Professor Park, a global leader in rust research, said that to date, 28 rust-resistance genes in barley have been identified worldwide.
Only four of these have been isolated so far, three by the Plant Breeding Institute (Rph3 being the third), making Dr Dinh's work very important.
Dr Dinh's journey to the laboratories of the University of Sydney is an interesting one.
Hailing from rural Vietnam he came to Australia on a scholarship to study, with a particular passion for agriculture because of his rural upbringing.
He is now in Japan, about to commence a year-long postdoctoral position to explore how to enhance soybean productivity.