Sunday, December 3, 2023

AgResearch expands work on GM grasses

Neal Wallace
Clover and endophyte products in development alongside HME ryegrass.
AgResearch is adding clover and endophytes to ryegrass to its work on genetically modified or gene-edited grasses.
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AgResearch is expanding its development of genetically modified or gene-edited grasses, adding clover and endophytes to its High Metabolisable Energy ryegrass, which has undergone field trials in the United States.

AgResearch has temporarily withdrawn an application to trial its High Metabolisable Energy (HME) ryegrass in Australia due to the complexity and volume of information required by regulators.

It has two other genetically modified products in development: a high-condensed tannin white clover, which early research shows can reduce methane emissions by 15%, and gene-edited endophytes to enhance pest protection while also reducing potential toxicity to animals.

An AgResearch spokesperson said scientists working with seed companies have identified what it believes is a molecular master switch that accelerates the production of condensed tannins, resulting in significant levels in white clover leaves.

“Condensed tannins are known to reduce urinary nitrogen and methane production from grazing animals, reduce bloat, reduce internal parasite burden, and improve animal productivity.”

Further research is needed, including animal feeding trials.

Similarly, scientists working with seed companies are seeking to enhance the value of endophytes, organisms that live within grasses and deter pests.

That pest resistance role has benefited the sector, but some endophytes contain compounds toxic to animals.

“The technology presents an opportunity to design endophytes, enhancing pest protection while also reducing potential toxicity to animals.”

Claims by GE Free NZ that the application for HME ryegrass field trials was withdrawn due to issues such as tainted milk are wrong, AgResearch science team leader Richard Scott said.

Following five years of field trials in the United States, Scott said, an application for field trials was recently lodged with Australia’s Office of the Gene Technology Regulator (OGTR).

The OGTR requested additional detailed analysis on an allergen known as sesame oleosin, that may be present and could be released in the pollen of the ryegrass.

“While AgResearch testing done previously had demonstrated that sesame oleosin is not expressed in the pollen of HME ryegrass, a more rigorous standard of testing is required by OGTR.”

Scott said given the time frame and complexity of this additional analysis, it was decided to withdraw the application, but it will be submitted again later.

In the interim, containment research will continue in New Zealand to prove the efficacy of the programme and to progress commercial application.

That includes further growing and animal feeding trials and plant breeding by the project’s commercial partners Grasslanz Technology, PGG Wrightson Seeds and DairyNZ.

HME ryegrass is the result of genetically modifying two genes to increase lipid content in the leaf and enhance photosynthesis in the plant.

This increases the nutritional quality of ryegrass but the research also suggests environmental benefits such as reduced methane emissions and nitrogen loss. 

“The trials done in the US achieved their purpose of proving the ryegrass could be successfully grown in an outdoor field trial setting with the increased lipid and energy content,” said Scott.

“We are confident that we can address the issue with access to trials in Australia and in due course, the programme will revisit the application to the regulator.”

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