“Potato Blight Effects”

Last week, I wrote about a disease-causing nematode that infects the roots of soybean plants and  a mutation in one strain of soybeans that makes them resistant to these nematodes. In the post I mused,

what if an already existing gene variant with a desired trait from one organism is genetically engineered into another organism of the same species? Would this make GMOs a little bit more palatable to their detractors?

While intended to be more of a thought experiment, a commenter alerted me to a very similar scenario playing out in Ireland, where potato crops are still affected by blight–yes, as in the blight responsible for the Great Famine of the mid-1840s. Blight makes potatoes rot and is caused by infestation of a fungus-like organism (oomycetes) called Phytophthora infestans.

In recent years, scientists have developed blight-resistant GMO strains of potato plants by introducing a blight-resistance gene called RB into the potato’s genome. This gene was identified in Solanum bulbocastanum, a wild potato plant native to Mexico that is closely-related to potatoes. Resistance to blight most likely developed as a result of coevolving with P. infestans, which is considered to be native to Mexico as well.

The scenario facing GMO potatoes, however, is a little bit different from the question I posed earlier since the RB gene isn’t found in cultivated potato plants. Furthermore, traditional breeding methods have been unsuccessful in making hybrids between cultivated potatoes and S. bulbocastanum, therefore necessitating genetic engineering. There are, however, other blight-resistant wild Solanum plants, such as Solanum venturii, that can be hybridized with cultivated potatoes. But using the RB gene from S. bulbocastanum remains the most attractive option because S. bulbocastanum is resistant to the most number of blight-causing P. infestans strains

The response from one anti-GM campaigner to using genetic engineering in this case?

It is just there to make GM more palatable to the general public. The fact that it comes from a related plant doesn’t make it any different. The real danger is the process.

I guess that answers my question.

5 thoughts on “Blight-Resistant Potato: an “Acceptable” GMO?

  1. I would be less concerned with the process of introducing a gene into a potato than I would be about the effect it may have on the potato’s native environment. For example, what if the fungus causing the blight, developed an immunity/resistance to this gene (similar to how bacteria can become antibiotic resistant)? Does GMO testing include an attempt to anticipate possible effects on the native environment of a species? If so, how long do those tests run and how successful are they generally?

    A concern that anti-GMO might have as well (I’m guessing here) is that if the potato cannot be successfully cross-bred with a resistant species, then is that nature just saying, “Yo, don’t mess with my stuff,” or is there another more benign explanation for why it can’t be done? Maybe simply that the two organisms don’t have the proper mechanisms for getting the genes where they need to go rather than the organisms are inherently rejecting the process (the analogy here might be: using a needle to make a blood transfusion to get the blood where it needs to go vs. the host rejecting that blood transfusion). I’m wondering if there is a difference in the minds of anti-GMO sentiment if the GMO is more like the needle in the analogy or more like something that would inhibit rejection of the newly introduced substance?

  2. “the effect it may have on the potato’s native environment. ”
    technically speaking, potatoes are a New World crop and are not native to Ireland/Europe.

    “Does GMO testing include an attempt to anticipate possible effects on the native environment of a species?” Good question. I’ll look into it.

    “Maybe simply that the two organisms don’t have the proper mechanisms for getting the genes where they need to go rather than the organisms are inherently rejecting the process”

    Hybrids can’t be made from crossing the resistant-wild potato plant with the susceptible potato crop because they are no longer compatible for breeding. Unless you mean, if crossbreeding were possible between the two plants…would the resulting hybrid inherit the RB gene? There’s no reason not to believe that it wouldn’t. For 1) it has been introduced into the potato genome by genetic engineering. 2) Other wild potato plants that have evolved different resistance genes to blight have been successfully bred with potato plants that are used for crops.

  3. This may seem like a novice question, but from how I see this debate, we should probably try to angle to the lowest common denominator:
    Do any current GE food crops use animal DNA? If so, how can I, as pro-GMO soldier, react rhetorically to one of these PETA types? I’m in WA state, where we vote on GMO labeling in November. As of yet, there’s no No campaign to speak of.

  4. “So while De Jong still devotes most of his time to honing his craft, he has recently begun to experiment in an entirely different way, with genetic engineering. To him, genetic engineering represents a far more exact way to produce new varieties, rather than simply scrambling the potato genome’s 39,000 genes the way traditional breeding does. By inserting a specific fungus-defeating gene into a tasty potato, for example, De Jong knows he could offer farmers a product that requires fewer pesticides.”


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