Bio-P potatoes

July 2015
Non-GM potatoes. Photo Creative Commons
The latest UK Government GM venture has been announced: GM potatoes designed to satisfy consumers, farmers and food processors.

First off the planned production line in a few short years will be potatoes containing a stack of novel genes: three to combat late fungal blight, two to ward off nematode soil pests, two to switch off the production of sugars and an amino acid which together have a nasty habit of producing a toxic derivative when heated, and one to switch off the enzyme which turns raw potatoes black when they're bashed.

Future GM potatoes are planned which will have increased nutrients and which don't sprout in storage. Also under investigation are weird potatoes for industrial starch production and vaccines-in-a-spud.

Novel potatoes for biofuel production are not to be developed as these would compete for food-growing land and are not considered the socially-preferred option.

The first win-win GM spuds are being developed with 90% taxpayer funding plus 10% from 'BioPotatoes' (BioP) UK Ltd. and 'Simplot' (USA): these biotech companies will, of course, reap all the profits from the final world-wide distribution.

BioP is figuring on using rising food prices and concerns about worsening food security as its "trump card" to win acceptance of GM potatoes. Seemingly, the public just need to be better informed (we've heard that one before), and the main problem has been the pesky environmentalists (we've heard that one before too, ad nauseam). Apparently, all that's needed to generate public acceptance is concrete, solid evidence from trials that the novel potatoes work as intended (is this an admission that none of the previous GM crops have actually worked?). And previous GM foods, such as golden rice, haven't been accepted because they only provided a single benefit, so the answer is to instill so many genetic incentives into a single potato that no one will be able to resist it (that one leaves us speechless).

And safety?

We are assured that "further extensive evidence of safety and environmental benefits" will be provided.


Funny that we never noticed the existence all this "extensive evidence of safety" which it seems is going to be furthered.

We have noticed, however, that potatoes are related to deadly nightshade and have a natural ability to generate toxins.

We've also noted that the discovery of the toxin produced by the reaction of a natural sugar with a natural amino acid when potatoes are heated was completely unexpected and, despite the length of time people have been processing potatoes, found only very recently. What does this tell us about the depth of our knowledge about the humble spud?

It hasn't escaped us either that when potatoes were selected for the development of GM safety tests (see Note below), pathological signs were found in the gut of rats fed on them. There was certainly no "further" nor "extensive" evidence whatsoever obtained after this finding because no one got a chance to look for it: the laboratory was closed and the GM potatoes destroyed before the cause of the problem could be investigated.

The logic that public distrust of one gene will be overcome by inserting a multitude of genes seems disingenuous.

What we seem to be looking at is a potato with eight novel genes (plus all the DNA paraphernalia needed to make them work) producing various anti-animal and anti-fungal substances, all leading to multiple physiological disturbances, and in a genetic background already adept at producing toxins. Funny that no one's mentioning special safety testing.

Neither, it seems, is any one considering environmental safety.

GM potatoes have long been considered low-risk because their pollen doesn't go very far and they don't produce any seed crop for processing which gets trucked around the world. A recently published paper has, however, highlighted the unexpected scale of post-harvest field contamination. It was found that, because only a narrow range of tuber sizes are accepted by the market, potatoes which don't conform are thrown back into the field. The extent of the discard can far outweigh the crop removed. Since potatoes propagate vegatatively, the discard can lead to a huge emergence of volunteers in subsequent crops for some years.

Potatoes are normally grown in a 1 in 4 rotation with cereal crops. This gap in repeat production is necessary because pests (such as blight) are harboured in crop residues.

To prevent gene flow from a GM potato crop to non-GM potatoes grown in the field, the authors suggest there would need to be a rotation with cereals of more than 1 in 4.

In light of this study, the UK Government promotion of multi-trait GM potatoes begins to make less and less sense:

  • The measures needed to control gene transmission from generation to generation are exactly the same as those needed to control pest transmission in successive generations of non-GM crops: this makes the artificial genes for pest-control redundant.
  • The method of harvesting is playing a major role in perpetuating the pests, perpetuating the genes, and in causing bruising of the crop.
  • Improved efficiency in harvesting techniques would make the artificial genes for pest-control and bruising redundant, and aid food security by providing more food per hectare from the crop.
  • Bruised potatoes will still be bruised potatoes even if you can't see a black bit, and bruises can harbour disease.

Also, slower processing at lower temperatures might well sort the toxin problem.

In a world where food prices and security are an increasing concern, land- and fuel-use efficiency should be a priority: stacks of genes designed to preserve the current expensive, wasteful systems of crop handling and processing are not a solution.

Genes which delay sprouting may well disguise, and therefore increase, the volunteer / gene-flow problem. Such genes will also mean we are being sold old spuds with waning nutrient levels: topping up lost nutrients with more engineered genes looks like another attempt at solving a problem by adding more problems.

Realistically, the potato market would be better served if cash were injected into improving how we handle the resources we already have, rather than by promoting clever GM fixes for industry to benefit from.

Note. Arpad Pusztai, working in Scotland on a Government contract to develop safety tests for GM foods in the 1990s, chose to work with potatoes because they naturally propagate vegetatively. Other GM plants must be cultured to generate whole plants from isolated cells after genetic transformation, a procedure which makes them subject to collateral physiological disturbances. GM potatoes are, thus, less likely than other GM plants to exhibit unexpected changes due to non-GM, factors.

  •, accessed June 2015
  • Funding approved to develop new potato at The Sainsbury Laboratory,, 1.06.15
  • S. Phelan, et al., 2015, Propensity for seed-mediated gene flow from potato crops and potential consequences for the coexistence of GM and non-GM potato systems, European Journal of Agronomy 67

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