Hill Laboratories creates world-first with new test for PSA

Hill Laboratories, New Zealand’s largest independent laboratory, has announced the development of a new test for the virulent strain of the kiwifruit disease PSA-V. The new test is faster and more accurate than any other available internationally.

The test is based around DNA sequencing of the infectious bacteria which creates the disease PSA (Pseudomonas syringaepv. actinidiae), and was developed in association with Plant & Food Research.

PSA-V is spreading progressively through kiwifruit orchards in the Bay of Plenty Te Puke area and beyond. Recently another 43 orchards were identified as being infected with PSA-V, which brings the total of identified infected orchards to 369. Signs of the bacterial disease, which severely damages and can kill kiwifruit vines, have become more evident with spring growth.

Special Projects Manager at Hill Laboratories, DrTerry Braggins, says the development of the new test is the result of several months of intensive work responding to the need of the kiwifruit industry.

“In association with Plant & Food Research we have geared the operations at our plant pathogen and diagnostic lab to develop this new test.

“It involved DNA sequencing of a number of strains of PSA and identifying areas of the sequence that were unique to PSA-V. This means the test is far more specific than the current methods. We are able to positively identify PSA-V with a single test, which means a faster and cheaper test for growers,” says Terry Braggins.

Kiwifruit growers are making big financial decisions on the future of their vines and a quick and reliable test is crucial to that decision making process.

Hill Laboratories has worked alongside the kiwifruit industry in New Zealand for a number of years in the area of soil and plant testing to ensure maximum benefit from fertilizer application, and also in monitoring the export crop for any pesticide residues.

Plant & Food Research PSA Response Manager Stuart Kay said the Institute accessed funding from the Ministry of Science and Innovation and the multi-partner Better Border Biosecurity programme (B3) to complete the DNA sequencing of 16 Psa isolates from around the world – including PSA-V.

“We recognise sequencing is a vital source of information for a range of programmes underway to combat PSA-V – from this and other tests through to ZESPRI’s and Plant & Food Research’s resistance breeding programme. Our sequence data is readily available to all PSA researchers and the work is ongoing. We are now continuing to sequence a further 24 isolates to give all researchers the best possible genetic picture of the bacteria”, says Stuart Kay.

The new PSA test will be available immediately to kiwifruit orchardists through Hill Laboratories in Hamilton. Click here to view Hill Laboratories Website

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