Tuesday, June 8, 2010

Anti-GM campaigners can't have it both ways

British scientists are to set up a 1,000-square-metre plot of genetically modified potatoes in Norfolk. The potato plants have been genetically modified by scientists at The Sainsbury Laboratory (TSL) to be resistant to "Late Blight" which is caused by a fungi-like organism called Phytophthora infestans.

The experiment is designed to tell whether GM potato plants that are resistant to late blight in vitro (that's in the laboratory) are also resistant to the pathogen in vivo (i.e. in the field), where there are a much larger number of different strains of P. infestans. If a fully resistant potato variety can be found, it could at least put a dent in the estimated £3.5 billion worth of losses that the disease causes worldwide every year.

Much of that cost is related to the use of fungicides - chemicals used to control fungi or fungi-like organisms. (By the way, although it's most appropriate to refer to P. infestans as a "fungi-like organism" and not as a fungi, the difference is very minor and one with which we need not concern ourselves here.)

Professor Jonathan Jones of TSL explains: "We have isolated genes from two different wild potato species that confer blight resistance Similar genes are found in all plants, and we are now testing whether these ones work in a field environment to protect a commercial potato variety, Desiree, against this destructive potato disease".

The group of scientists screened about 100 different wild species of Solanum, the grouping of plants to which potatoes belong and identified just a handful that were resistant. The next step was to isolate genes and insert them into the commercially available potato variety Desiree. Watch a video of the process here.

The modified plants can now recognise the onset of late blight attack and can trigger the plant to switch on its own defence mechanisms. By switching on these plant-based defences, it may drastically reduce the levels of fungicide which need to be applied.

Despite this good news, anti-GM campaigners have once again come out against such trials. Kirtana Chandrasekaren, Friend of the Earth's Food Campaigner accused the British government of "wasting millions of pounds of taxpayers' money by forging ahead with unnecessary and unpopular GM trials.
"We can feed a growing global population without trashing the planet or resorting to factory farms and GM crops - the Government must help farmers shift to planet-friendly farming" said Chanrasekaren.

Dr. Helen Wallace of the campaign group GeneWatch also called the trial a "waste opf public money" and suggested that "it is possible to breed blight-resistant potatoes using conventional methods, so there is no need to use GM technology".

"anti-GM campaigners need to make a choice"What Dr. Wallace and the campaign groups fail to grasp is that it has been nearly 160 years since the end of the Irish Potato Famine when one million people died of starvation and further one million people emigrated to survive. In those 160 years of conventional breeding, a tiny handful of varieties have been produced with full resistance to the pathogen and their propagation has been severely limited by consumers opting for older, more familiar varieties.

So, anti-GM campaigners need to make a choice. Either we stick with existing varieties and pump millions of tonnes of fungicides into them every year or we opt for a slightly modified version of a commercially relatively successful variety which can defend itself from late blight, reducing fungicide use significantly in the process. The campaigners can't have it both ways.

A previous post on this blog also dealt with the issue of consumer acceptance of GM crops.


Mitchell Selfdrive June 16, 2010 at 10:04 AM  

I enjoyed the article, but feel obliged to point out that the differences between oomycetes (which is what Phytophthora is) and fungi are not 'very minor'. You might as well say that bats are birds, for all practical purposes, as the differences are 'very minor' (and bats and birds are more recently-diverged from each other...) ;)

Oomycetes are heterokonts, with a number of highly significant differences from fungi (see, for example, http://www.apsnet.org/online/feature/oomycetes/). Even from a purely practical point of view, the (major) differences in cell wall composition may affect potential control methods.

Science Writer June 17, 2010 at 9:58 AM  

Thanks for your comment Mitchell.
I may well have oversimplified the differences between the oomycetes and the fungi. I fully accept your point but for the general reader, the ease of bunching them in with the fungal-plant pathogens (as Agrios does)is useful from a plant-pathology point of view. From a taxonomic point of view, I can see why that would be frowned upon :)
Thanks for reading.

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