A single test to detect multiple plant viruses

Researchers from the Plant Biosecurity Cooperative Research Centre (PBCRC) have developed a diagnostic toolkit that can accurately detect plant viruses and viroids in a single test.

The toolkit will be mainly used by post-entry quarantine (PEQ) facilities operated by government quarantine agencies. As explained by project leader Dr Roberto Barrero, these agencies play a pivotal role in keeping Australia and New Zealand safe from exotic viruses.

“Currently, we know about 5000 viruses, and every week, more viruses are discovered,” said Dr Barrero, who is based at Murdoch University. “The current existing quarantine screening protocols only screen for a single virus, or a handful of these viruses. This means it is a significant challenge to screen comprehensively a large volume of imported plants against an ever-increasing number of viruses.”

According to Dr Barrero, the researchers needed to find a solution that was scalable, robust and highly sensitive. To do this, they looked to the plant’s own immune system.

“Plants are smart,” said Dr Barrero. “They can actually recognise viruses, and chop these viruses into small pieces. So in this project, we take these small pieces and read the genetic information contained in these pieces to reconstruct the viruses. So essentially, it’s like putting together a puzzle.”

Because plants can look for multiple viruses at once, said Dr Barrero, the researchers are now able to screen against all known viruses in a single experiment. According to Mark Whattam, a plant pathologist at the national PEQ Facility in Victoria, the test will “significantly reduce the time imported plant material spends in Australia’s quarantine system, while improving accuracy of detection”.

“The toolkit has many benefits for our operations, including improved sensitivity, reduced screening costs and the reduction of manual screening times, which can currently take more than two years,” Whattam continued.

“It means that imported material such as elite cultivars and breeding lines will be available to Australian plant breeders and nurseries as much as 12 months sooner.”

The Australian Government has already accepted and adopted the technology in the toolkit as the new PEQ standard for the screening of viral pathogens in clonal grasses. Further rollout of the technology will includes hands-on and remote workshops for biosecurity professionals, not only providing training in the use of the toolkit but also gathering feedback to improve usability.

“There is further potential for state agriculture departments, diagnostic laboratories and research institutions to use the toolkit, not to mention developing countries that are often highly dependent on agricultural imports and exports,” said Dr Barrero.