Friday, March 29, 2024

‘Green’ grass hits hurdle

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AgResearch scientists have developed a genetically modified ryegrass that cuts greenhouse gas emissions by up to 30% but biotechnology experts warn regulations could delay its use.
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Though it has several environmental benefits and could boost production it faces regulatory hurdles here because it has been genetically engineered.

The scientists have shown in the laboratory the ryegrass, called High Metabolisable Energy (HME), can reduce methane emissions from animals by 15% to 30% while modelling suggests a reduction in nitrous oxide of up to 20%.

It has also shown resilience to dry weather and can increase milk production by up to 12%.

Environmentalists have berated agriculture for not reducing greenhouse gas emissions but if laboratory results are replicated in the field, HME could reignite the GM debate.

AgResearch Grasslands principal plant biotechnology scientist Greg Bryan said HME could transform NZ farming by reducing its environmental footprint and improving animal productivity.

“The potential value to GDP based on modelling we have done is in the range of $2 billion to $5b a year in additional revenue depending on the adoption rate by farmers.”

But New Zealand’s regulations mean HME field trials would have to be done overseas then repeated here.

Earlier last week scientists and science leaders attending a NZ BIO symposium at Massey University warned NZ’s GM laws had not kept pace with technology such as gene editing.

Much of the developed world was embracing GM and while NZ scientists were leaders in this science, regulations might prevent its use.

Approval for field trials was technically possible but realistically difficult, with restrictions that no reproductive material left the site, thus preventing plant breeding studies.

In an interview after the symposium, Bryan said international science companies were not interested in a small, temperate, pastoral farming system, making HME a NZ solution to a NZ farming system problem.

The 15-year HME project cost AgResearch $24 million with another $24m expected to be spent before it was ready for commercialisation.

The science involved doubling the level of leaf lipids or fat concentration in the ryegrass plant, which increased available metabolic energy.

That change gave improved fermentation in the rumen, reducing excreted nitrogen in urine while the associated extra fat in the animal’s diet reduced methane emissions by up to 30%.

It was also expected to boost milk production by between 6% and 12%.

Bryan said the biomass of the ryegrass plant was about 40% more than conventional plants while tiller growth rates in the lab were 25% to 50% greater than other ryegrass varieties.

It had shown tolerance to dry weather, was deeper rooting and retained more energy after harvesting but would need to be carefully managed.

“It means farmers should have a lot more feed available with more energy.”

Nick Roberts, a principal plant biotechnology scientist, said transgenic technology doubling the level of leaf lipids was the only way to achieve those changes.

“The modified proteins enable the leaf cells to produce and store double the level of lipid but once in the rumen they are degraded in the same way unmodified proteins are.”

Seed multiplication in containment glasshouses was under way ahead of field trials planned for 2018-19 and animal nutrition trials in 2020. Depending on those results approval would be sought for NZ trials.

Bryan said GM organisms had been used for over 20 years in agriculture and the growing number of products on the market had not caused health issues for humans or animals eating them.

During development of HME scientists discovered elevated photosynthesis which enabled tropical plant growth rates for temperate climate plants.

This technology has drawn the attention of the Gates Foundation which could see benefits for rice production in third-world countries.

Bryan said it had also attracted several United States investors who wanted to use it in soybeans with licence revenue flowing back to AgResearch.

But just as importantly, US scientists would also work on the technology but AgResearch would have access to their findings with rights to use them here.

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