MEDIA RELEASE: TE PŪIAKI PUTAIAO MATUA A TE PIRIMIA SCIENCE PRIZE

Dr Linda Johnson and the Endophyte Discovery Team from AgResearch have been awarded Te Pūiaki Putaiao Matua a Te Pirimia, the Prime Minister’s Science Prize.

They have been awarded this prize for generating significant economic and environmental benefits from their work on beneficial plant partners called endophytes.

Ryegrass endophytes

Dr Linda Johnson is the Science Group Manager for Resilient Agriculture and a Principal Scientist at AgResearch. She explained that endophytes are microorganisms, usually bacteria or fungi, that live within a plant and help rather than harm it.

“We’ve been interested in endophytes for a long time because they provide a sustainable solution to agriculture, reducing inputs by controlling pests and diseases,” Linda said.

Perennial ryegrass is the predominant species in New Zealand pastures, alongside clover, and its fungal partner lives in the above-ground section of the grass and produces chemicals that help protect the plant from insect damage. “The endophyte protects it from insect pests and the endophyte gets a safe home.”

The partnership is so close that the endophyte fungus is incorporated into the ryegrass seed. This means that when settlers from Europe brought ryegrass seed with them to start farming in New Zealand, they introduced ryegrass endophytes too, Linda explained.

Discovery of toxicity

For many years during the mid to late 1900s, farmers were seeing a lot of health and welfare issues in their grazing animals and were desperate to know how to prevent these issues.

One highly recognisable problem is ryegrass staggers, a neuromuscular disorder where animals stagger around, as if drunk, and can badly injure themselves.

Team member Dr David Hume, a Senior Scientist at AgResearch, remembers their Lincoln-based team’s “momentous discovery” of 1981 – finally the ryegrass endophyte was found to be the cause of ryegrass staggers. This spurred further endophyte research that uncovered other animal welfare issues and animal productivity losses such as summer-autumn ill thrift, that were linked to endophyte.

At first, people thought the solution was to remove endophytes from pastures, Linda said. “But if you remove the endophyte, you also remove the ability of the plant to withstand the huge amount of insect pressure that’s present in New Zealand pastures.”

Pastures are challenged by six main insect pests in Aotearoa, both introduced and locally occurring, such as African black beetle, Argentine stem weevil, porina larva and grass grub.

Searching for better endophytes
Instead of removing the endophyte, the research team started searching for safer endophytes, ones that would still protect the grass from insects but not produce toxins harmful to grazing animals. All ryegrass endophytes in New Zealand were found to produce the same toxins, so the team screened new endophytes from ryegrass seed sourced from all over the world.

This is where the team’s multidisciplinary skills were needed: mycology, microbiology, molecular biology, chemistry, plant breeding, animal science, entomology, plant physiology and agronomy, to name a few. They needed to understand the chemistry of endophyte toxins but also the “intimate relationship” between the endophyte and the ryegrass, which enables the endophyte to be taken into the seed and remain viable once the seed is planted. They also needed to study how new endophytes affected the growth and health of both the pasture and grazing animals.

Discovery of AR37 endophyte
Endophyte AR1 was the first endophyte that was commercially produced through the team’s work, but endophyte AR37 has been the game changer.

“AR37 has been a win-win,” David said.  “It’s delivered increased pasture production and persistence but, equally, it has reduced the detrimental effects of ryegrass staggers and removed the limits on animal productivity in our sheep, beef and dairy sectors.”

“We didn’t have to compromise on insect protection to get improved animal safety – AR37 actually gave us better insect protection than the endophyte that was widespread in our environment. We never thought this was possible until we discovered AR37,” David said.

Through protecting pasture from five of the six main insect pests, trials showed that the AR37 endophyte also increased the dry matter yield of the grass by 12%, leading to gains in meat and milk production, and allowing the grass to survive for much longer.

Dr John Caradus, from Grasslanz Technology, a subsidiary of AgResearch, has been involved from the beginning. His role was to link the outputs from the research team with the needs of farmers, aided by the commercial partners that manufacture and sell the seed with the endophyte fungus in it.

“The uptake of endophyte by New Zealand farmers has been exceptional. They have seen that they can benefit their animals and their pastures by using novel endophytes.”

Seven years from when the new endophytes were first introduced on the market, 80% of the ryegrass seed sold in New Zealand contained the improved endophytes.

They have also had some independent estimates of the economic gains.

“Over 20 years, the AR37 endophyte alone will have added about $3.6 billion to the New Zealand economy through both improved pasture persistence and productivity but also reduced animal health and welfare issues,” John said.

World-leading research and development
John says New Zealand has excelled in both the research and the delivery of new endophytes.

“Many teams have studied endophytes globally, but it was the New Zealand team that were the first to understand the chemistry of endophytes in the pasture and then identify useful strains.”

Second, New Zealand was able to form “hardwired links” through to seed companies that were prepared to take the risk of producing and marketing these new endophytes to farmers, not only in New Zealand but also in Australia and the United States of America.

The researchers believe that their work on endophytes can deliver more benefits. “Endophyte research in New Zealand must continue because of the environmental issues we are facing at the moment,” John said.

Already it has been found that ryegrass with AR37 endophyte has deeper roots, and that this can help under drought conditions. With new gene technologies, it may be possible for endophytes to produce chemicals that can curb methane production in grazing animals, helping New Zealand reduce its greenhouse gas emissions, he said. Expected changes to gene technology regulation in New Zealand will reduce some barriers to their research on novel endophytes.

Advances are also being made by the team to develop new endophytes for cereal crops that result in protecting them from economically important plant disease and insect pests, Linda said. This development has simulated some international interest.

On winning the prize
Linda says winning the Prime Minister’s Science Prize will support the research team to continue its work.

“We’re really interested in climate resilience and understanding how the endophyte could provide heat tolerance or provide benefits for the plant to take up nutrients and some other traits that are really important for farmers to have.”

She said the prize recognised decades of work. “Most of the Endophyte Discovery Team have actually dedicated their careers to endophyte science so it’s absolutely fantastic for the team to get this recognition.”

“We also hope our prize will shine some light on agricultural research and show the impact this research has had on farmers and the New Zealand economy.”

 

Read more about this prize.