Researchers at the Centre for Crop and Disease Management (CCDM), co-supported by Curtin University and the Grains Research and Development Corporation (GRDC), are using digital Polymerase Chain Reaction (dPCR) cancer detection technology to discover fungicide resistance mutations in crop disease.
Dr Fran Lopez-Ruiz, leader of the CCDM’s Fungicide Resistance Group, said the technology enabled his team to run ‘a fine tooth comb’ through multiple samples at once, picking up DNA mutations that may have been missed with previously-used laboratory methods.
“Since the first occurrence of wheat and barley powdery mildew symptoms in 2015 until the end of the season, dPCR gave us the ability to genetically screen over 140 samples for any signs of known mutations associated with fungicide resistance, at a much faster rate and with extreme sensitivity,” Dr Lopez-Ruiz said.
“Previously, screening this number of samples would have taken us nearly two years, with a much lower detection level.
“Using this technology, mutations associated with the early stages of DeMethylation Inhibitors (DMI) fungicide resistance were detected for the first time in Australian wheat powdery mildew samples collected from Tasmania and New South Wales.
“The results were communicated to growers, allowing them to appropriately control disease and better manage fungicide resistance.
“Also for the first time, we detected a mutation associated with high levels of DMI fungicide resistance in barley powdery mildew samples from outside of Western Australia in New South Wales, Victoria and Tasmania.
“With this information, it is now clearer than ever before that fungicide resistance is widespread and becoming an increasing threat to growers, requiring integrated disease management options to slow down the rise of resistance mutations,” Dr Lopez-Ruiz said.
dPCR works by allowing researchers to collect multiple samples from one crop, pool them, and extract fungal DNA to look for resistance mutations. dPCR is also capable of quantifying the amount of DNA that contains the resistance mutations.
“We are now increasingly confident in our ability to detect signs of fungicide resistance before it becomes a problem to growers,” Dr Lopez-Ruiz said.
“dPCR is bringing mutation detection into the digital age and we look forward to unlocking new information on fungicide resistance in other important pathogens in the 2016 season.”
Dr Lopez-Ruiz said to slow down the rise of resistance-endowing mutations, growers should be using multiple strategies such as seeding resistant cultivars, using crop rotations, stubble management, controlling the green-bridge, and rotating their fungicides, or using fungicide mixtures, with different modes of action.
CCDM director, Professor Mark Gibberd, said this early detection research by Dr Lopez-Ruiz and his team was a direct example of how the CCDM was providing innovation to the grains industry by leveraging off discoveries in other areas of research.
“The co-investment between GRDC and Curtin University allows CCDM research to be responsive to the needs of farmers across the Australian agricultural industry,” Professor Gibberd said.
“By thinking outside the box, we are enabling the rapid development and adoption of new technologies, such as dPCR, and I look forward to seeing the next innovation that helps growers improve their profitability and sustainability.”
During the 2016 season, growers outside of Western Australia affected by barley or wheat powdery mildew are urged to submit a sample to the CCDM for fungicide resistance testing. For a sampling kit, email firstname.lastname@example.org or phone (08) 9266 1204.