The test is the culmination of a five-year Better Border Biosecurity (B3) project led by microbiologist Sandra Visnovsky.


It focused on Pseudomonas, a group of more than 100 species, some of which cause serious bacterial diseases in plants.


Visnovsky says the project’s main task was to help Biosecurity New Zealand (the biosecurity arm of the Ministry for Primary Industries) detect harmful bacteria faster.


“We were focused on how to test and quickly determine whether plants in quarantine at the border are infected with disease-causing bacteria.


“Pathogenic (disease-causing) pseudomonads are challenging to distinguish from others that are harmless and typically would need species or strain-specific tests, but not all pathogenic strains are known.”


Researchers found genetic clues that helped to differentiate the two.


“We used the latest genomic technology to identify virulence markers that can be used to differentiate Pseudomonas that will cause disease from those that won’t.


“We then developed a specific PCR test to distinguish strains which are pathogenic and could present a risk to our country’s biosecurity, regardless of whether the species of bacteria were identified or not.”


Biosecurity New Zealand’s bacteriology and botany team manager Robert Taylor says the new PCR test is now routinely used by BNZ staff.


“The test is now regularly used to ‘do detective work’ on plants. The real value of this test is when bacteria detected cannot easily be identified.


“Plants identified as having potentially-disease-causing bacteria would get further scrutinised with more specific tests as part of our practices.”


Taylor says since it was first used in the BNZ laboratory over two years ago, the plant PCR test has saved time and money and sped up the pre-border quarantine and testing process for imported woody plants.


B3 is a research collaboration that connects scientists from Crown Research Institutes and Lincoln University with organisations concerned with border biosecurity such as BNZ, with industry and Māori/iwi to help protect Aotearoa New Zealand’s plants from exotic pests and pathogens.


Find out more about the B3 project and read a scientific publication.