Grower samples from last year’s season, along with a machine normally used for detecting mutations in cancer cells, have led to the discovery of the first signs of mutations which could lead to fungicide resistance issues in wheat powdery mildew in Australia.
Digital Polymerase Chain Reaction technology picks up mutations
Researchers at the GRDC-supported Centre for Crop and Disease Management (CCDM), based at Curtin University, are using digital Polymerase Chain Reaction (dPCR) mutation detection technology to discover fungicide resistance due to mutations in crop disease, and are calling for more powdery mildew samples from outside of Western Australia for the 2016 season.
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.
“Using this technology, a mutation 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,” Dr Lopez-Ruiz said.
“Also for the first time, we’ve 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 has never before been clearer that fungicide resistance is widespread and becoming an increasing threat, requiring integrated disease management options to slow down the rise of resistance mutations,” Dr Lopez-Ruiz said.
Faster and more sensitive screening with dPCR
Analysing 140 samples from the 2015 season, CCDM’s Fungicide Resistance Group was able to genetically screen the samples for any signs of known mutations associated with fungicide resistance, at a much faster rate and with extreme sensitivity. Previously, screening this number of samples would have taken nearly two years, with a much lower detection level.
“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.
Submit a sample for fungicide resistance testing
During the 2016 season, growers outside of WA affected by barley or wheat powdery mildew are urged to submit a sample to the CCDM for fungicide resistance testing. For a free sampling kit, email firstname.lastname@example.org or phone 08 9266 1204. Visit the CCDM website for more information on How to send us samples.
- Management of barley powdery mildew in 2016 – fungicide resistance (DAFWA )
- Fungicide Resistance Group
- Follow the Centre for Crop and Disease Management @theccdm and the Fungicide Resistance Group @FRGCurtin on Twitter
Dr Fran Lopez-Ruiz, Megan Meates and Alexandra Kay, Centre for Crop and Disease Management