Kauri dieback and myrtle rust research to be accelerated

Research, Science and Innovation Minister Megan Woods has announced a funding increase of $13.75 million over three years from the Strategic Science Investment Fund (SSIF) for research to combat the spread of kauri dieback and myrtle rust.

The Biological Heritage National Science Challenge is developing the platform plan for the SSIF.

Kauri dieback is threatening the country’s kauri with extinction and myrtle rust is threatening many iconic native species.

The new investment will be used to focus and accelerate the work already being done by Government agencies, councils, research providers, Māori and interest groups. A high-level strategy is being developed by the BioHeritage Challenge.

The strategy will align with BioHeritage’s three big goals – empower, protect, restore – and the research priorities already identified by the kauri dieback and myrtle rust Strategic Science Advisory Groups (SSAGs).

BioHeritage leader Dr Nick Waipara, of Plant & Food Research, says a core group of people with diverse expertise is being brought together to develop the strategy and subsequent workplan.

“While details are still being confirmed, it’s our intention to work closely with all key players as the strategy is developed. There has already been a lot of careful thinking about research needs in these areas and it’s our intention to build on this – not start from scratch.”

Dr Waipara  says kauri dieback and myrtle rust are critical threats to New Zealand’s environment and the team is acutely aware of how urgently something needs to be done to stop the diseases spreading.

“Connecting experts from diverse institutions is what National Science Challenges are all about – we independently focus collective thinking on nationally significant problems such as kauri dieback and myrtle rust,” he said.

“An integral part of this is to work closely in partnership with Māori.

“While we’re realistic about what can be achieved in three years, we feel confident that our collective approach will help make a big difference for Aotearoa.”

Source: Biological Heritage National Science Challenge

Kauri dieback fungus may have been in NZ for longer than previously believed

Phytophthora agathidicida (PTA), the fungus-like organism that causes kauri dieback, has been in New Zealand much longer than previously thought, a study led by Bio-Protection Research Centre researchers based at Massey University suggests.

Plant geneticist Dr Richard Winkworth and collaborators have been using genome sequencing to investigate when PTA arrived and how it has changed since arriving.

“It had been suggested that PTA arrived in New Zealand not long before the first diseased trees were found in the early 1970s,” Dr Winkworth says.

“However, our results suggest PTA was diversifying in New Zealand kauri forests around 300 years before that. It must have arrived even earlier. Humans may have brought it here – perhaps the pathogen was carried to New Zealand by Polynesian settlers or the earliest European explorers – or it may even have been here before humans arrived.”

The researchers have sequenced and analysed complete mitochondrial genomes of 17 PTA samples collected from sites across the geographical range of the disease.

“The samples we have collected suggest several genetic subgroups within PTA,” Dr Winkworth says.

“To better understand the history of spread through the kauri forests we need to increase our sample size. However, we do see, for example, that several genetic subgroups are present in the Waitākere Ranges, perhaps as the result of human activity.”

These results raise an important question: If PTA has been in New Zealand for at least the last 300 years, why has it only recently become a significant problem?

“The results suggest that the relationship between PTA and its host may have changed,” Dr Winkworth says.

There are several ways this might have happened. One is that genetic changes to PTA have made it more virulent. “It is a possibility, but our results suggest it is not as simple as a single pathogenic form evolving and spreading through the forest,” Dr Winkworth says.

An alternative is that environmental changes have resulted in the disease emerging. The research results are consistent with this possibility.

“Since humans arrived, we have been altering New Zealand environments. Perhaps the combination of heavily fragmenting the kauri forests together with ongoing human-mediated disturbance and climate change has led to emergence of the disease. Perhaps we introduced another pathogen that, in combination with PTA, results in disease.

“If we are to fight back effectively we need to better understand the relationship between when PTA arrived, its pattern of spread, and the emergence of kauri dieback disease,” Dr Winkworth says. “Identifying why kauri dieback disease emerged might help us to move beyond containment to managing and controlling it.”

The research team has also been developing a cheap, robust DNA test that is simple enough for community groups to use in the field, but that is as accurate as laboratory-based testing.

“We are hoping to evaluate the test in field trials in the next few months.” Dr Winkworth says. “We hope that this will make it easier to monitor where PTA is, both for the purposes of management but also to enable further research.”

This Massey University-led research has been largely funded by the Bio-Protection Research Centre, and has involved researcher contributions from Manaaki Whenua Landcare Research, Toi Ohomai Institute of Technology, Scion, and the University of Auckland.