Pushing the boundaries

By Geoff Cumming

A decision allowing GM experiments on our most populous tree, pine, raises questions over the adequacy of rules set 15 years ago to cope with emerging technologies

Terry cites kiwifruit as an example of a crop that could be inadvertently contaminated through the spread of pollen from pines with ZFN-altered DNA. Photo / Thinkstock
Terry cites kiwifruit as an example of a crop that could be inadvertently contaminated through the spread of pollen from pines with ZFN-altered DNA. Photo / Thinkstock

They are novel DNA-changing techniques that blur the lines around what is and what isn't genetic engineering. Their names alone are fuse blowing: zinc-finger nuclease (ZFN), TALENs (transcription activator-like effector nucleases), cisgenics, oligo-directed mutagenesis (ODM) and others.

These molecular technologies, which target specific genes, offer potential to breed crops, trees and animals with desirable traits and block out less desired aspects more accurately and efficiently than traditional GM and non-GM techniques.

Scientists around the world can see the potential but the big question is whether or not the organisms created with these emerging technologies are GMOs. The answer is posing headaches for regulators worldwide.

Our agency, the Environmental Protection Authority, has decided that a technique using a type of ZFN in tandem with TALENs falls into a category that is exempt from our GM regulations, putting New Zealand at the forefront of this debate.

The Sustainability Council, challenging the decision in the High Court next week, says out in front is no place to be for a nation whose food exports attract a premium for our association with GE-free production and before important export markets have got their heads around ZFN.

The case is the first challenge to an approval under 1998 regulations which followed the passing of the Hazardous Substances and New Organisms (HSNO) Act, which covers GM research. As a measure of what's at stake, US agrichemical giant Dow, which has developed a number of ZFN products, tried unsuccessfully to be joined to the proceedings as an interested party.

Scion, our forest research institute, wants to use the technologies to change the DNA of our most populous tree, pinus radiata, the backbone of our forestry exports. It believes the techniques could help to develop stronger and better quality wood for building, faster-growing trees for pulp and paper production, improved disease resistance, even trees which are sterile to prevent the spread of wilding pines.

Scion's general manager of manufacturing and bioproducts, Elspeth MacRae, says the techniques are "a million miles away" from genetic modification as it was understood at the time of the 2001 Royal Commission.

MacRae says the technology allows very precise targeting within the genome sequence and does not introduce foreign DNA. It would normally be used to delete undesirable DNA, though DNA could be added. The key modification occurs as the cell undertakes normal DNA self-repair.

An EPA committee in April decided that though the techniques would result in a genetically modified organism under the definition in the act, they met criteria for an exemption from regulatory controls which prevent the uncontained release of GM organisms. The exemptions include organisms regenerated from cell culture including those produced through cell fusion, and the EPA decided the ZFN techniques proposed were close enough to fit this category.

Its decision overrode the recommendation of EPA staff, who concluded the techniques were closer to GM than non-GM techniques because of their reliance on in vitro (test-tube or culture dish) techniques, with engineered proteins injected into the cell and maintained outside the living organism to modify the genome.

But the committee also noted that its determination "highlights the need for a review of the [HSNO] regulations as they are not keeping pace with a rapidly evolving field of science". The Ministry for the Environment says it will await the outcome of the court case before deciding whether to proceed with a review.

Scion already has approval to field test pinus radiata with genetic modifications in containment on a 4ha site at its Rotorua campus. The modifications cover plant growth and biomass acquisition, reproductive development, herbicide tolerance, wood density and dimensional stability. The 25-year approval requires that no heritable material (pollen and seed) escapes from the field test site and trees must be destroyed before they reach 8 years.

But the latest decision would allow Scion to field test pines modified using ZFN-1 without containment.

Scion says plants developed using these techniques will be indistinguishable from plants modified using traditional genetic mutation (mutagenesis) techniques. The process it plans to use is known as ZFN-1. Other types, ZFN-2 and ZFN-3, produce different mutations with ZFN-3 regarded as more akin to transgenics (GM). They sit on a raft of emerging technologies which produce targeted mutations.

Sustainability Council executive director Simon Terry says the novel techniques show scientists are finding ways to "invent around" regulations covering GM. The decision exposes our economy to risks, Terry says, such as overseas markets rejecting products associated with the technology. "Should organisms resulting from ZFN-1 be field-trialled or commercially cultivated in New Zealand and export markets subsequently deem them to be GMOs, this could have significant negative economic impacts on food exporters."

Scion's application says there is currently little information on how regulatory authorities internationally will classify crops derived using these techniques.

Australia's gene technology regulator has indicated that a crop modified using ZFN-1 would likely not be considered a GMO.

In the US, the Department of Agriculture has approved targeted GM approaches, including ZFN-1 and ODM, which direct the modification of an existing gene without adding foreign DNA.

Terry says Australia's GM laws are not comparable to New Zealand's while the US Federal Government barely regulates GM at all.

In Europe, a working group is considering the state of research and commercial implications.

"It sets up the potential for exporters to inadvertently send traces of a ZFN organism to Europe and potentially trigger market objections," Terry says.

He cites kiwifruit as an example of a crop that could be inadvertently contaminated through the spread of pollen from pines with ZFN-altered DNA.

He argues New Zealand should instead concentrate on exploiting the advantages of consumer perception that its food products are GE free, and the price premium which these products are increasingly gaining overseas.

Though unable to discuss the detail of the High Court case, Terry confirmed it would consider whether the exemptions listed in the 1998 regulations are specific or can be stretched to include technologies such as ZFN. "The question before the court is whether the existing regulations are limited to a well-defined set of techniques or whether the EPA can expand that list."

If allowed to stand, he says the decision raises the risk that other gene-targeting techniques that manipulate DNA could stand outside regulatory coverage.

"It would effectively deregulate the technology so it was not covered by New Zealand's hard-won GM protections. The technology could be applied to food, fibre, any application be it indoors or outdoors without any prior notification or approval by any regulatory authority."

However, the EPA committee stressed its determination did not address the use of ZFN-2, ZFN-3, TALENs or other hybrid proteins to induce genetic changes using DNA self-repair mechanisms.

Other research institutes interested in using ZFN-1 techniques include AgResearch, which is evaluating their use for targeted livestock genome modifications.

Crown-funded research consortium Pastoral Genomics hopes to release GM ryegrasses modified using cisgenics, which introduces DNA from the same or cross-compatible species to produce desired traits such as drought-resistance.

- NZ Herald

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