Researchers from the Centre for Crop and Disease Management (CCDM) have discovered a genetic solution for Australian barley growers against powdery mildew disease, potentially saving the industry millions of dollars.
Globally, powdery mildew causes significant damage to barley yields. In Australia alone, direct losses and control costs can set growers back by up to $100 million per year.
Published in Nature Scientific Reports, lead researcher Dr Simon Ellwood and his team at the CCDM – which is co-funded by Curtin University and the Grains Research and Development Corporation (GRDC) – have for the first time found a gene within an Ethiopian barley landrace that is resistant to all forms of powdery mildew, without affecting yield.
“Currently, the best genetic resistance to powdery mildew in barley involves the mlo-11 allele, which has been widely deployed in Europe and the USA for more than 40 years and provides resistance to all known pathotypes of mildew,” Dr Ellwood said.
“However, while successful at preventing powdery mildew, mlo-11 has been shown to reduce yields by causing tissue damage in leaves and hence reducing the plant’s photosynthetic capacity.
“We’ve found a promising new resistance that is a variant of mlo-11. This variant is structurally different and does not possess known side-effects effects of the mlo-11 allele and, therefore, does not affect the plant’s ability to photosynthesise, ultimately maintaining production levels.”
Professor Mark Gibberd, CCDM Director, said the finding could not come at a better time for growers, particularly as powdery mildew pathogens had become resistant to DMI fungicides in many areas of Australia, reducing control options for growers.
“This recent discovery demonstrates the benefits of progressing research into fungal pathogens along multiple pathways of discovery,” Professor Gibberd said.
“While monitoring the in-field changes of the pathogen enables us to inform the industry of the need for any practice changes, concurrent research into the plant’s resistance enables industry to develop long term solutions to key diseases.”
Dr Ellwood said his team was now bulking up the seed for breeding companies to ensure the resistance could be included in new barley varieties. If taken up by the breeding companies, barley growers could expect better resistance to powdery mildew in their crop within the next few years.
The team has been screening exotic barley lines from other countries, including China, Ethiopia, Uzbekistan and Turkey, for some time.
The process involves growing the plants and testing them for resistance after infecting them with powdery mildew. Dr Ellwood said the key was to look for resistance other than major dominant resistance genes, which inevitably break down in the field.
“It’s an arduous task, and takes many years, but it is well worth it when you find a solution to a major economic challenge for the agricultural industry,” Dr Ellwood said.
“At a time when fungicide resistance is becoming a major problem for Australian grain growers, I’m delighted my team has found a genetic resolution to assist in preventing powdery mildew infection, meaning less need for fungicides, and allowing growers to become more sustainable and profitable.”
The paper, Tempered mlo broad-spectrum resistance to barley powdery mildew in an Ethiopian landrace, can be found here: www.nature.com/articles/srep29558
