Messing With Gene Expression in Corn

  • Published on April 29th, 2010


A study is about to be published by scientists at the independent RIKILT – Institute for Food Safety in Wageningen, Netherlands.  It will appear in the next edition of Plant Biotechnology Journal – a prestigious, peer reviewed publication.  The study followed gene expression, protein levels and other metabolites associated with 60,000 genes in corn.  They compared different corn hybrids, GMO and non-GMO lines, and different growing locations.  Guess what they found?

“The researchers concluded that the environmental influences led to a far greater variety in gene expression, proteins and metabolites than did the different genotypes.” 

So it seems like “Mother Nature” is messing with gene expression more than any corn breeder or biotechnologist.

Independent Testing

This work represents “independent testing” by a group that is skeptical about GMOs.  One of the “precautionary principle – driven” arguments against GMOs in Europe has been the possiblity that GMO crops will have unanticipated changes in gene expression.  This study suggests that if Europeans want to prevent any unexpected changes in genetic expression in corn, what they really need to do is to ban weather and soil differences.  It looks like there is more variation than they can ever sort through for a “complete safety assessment.”

Not Surprising

This result is actually not surprising.  There are many well known ways that the environment changes the way a plant grows, and many of those changes have to involve changes in gene expression.  The quality of bread wheat is highly related to weather – so much so that bakers have to shift where they buy their wheat year to year to get the quality then need.  Corn growing under heat and drought stress becomes much less able to protect itself from infection by Aspergillus flavus which can lead to contamination with the deadly mycotoxin, aflatoxin.  Corn seedlings “see” whether there are weeds growing near them very early in the season (based on near infrared reflectivity – they don’t respond to the wavelengths reflected from other corn plants) and they shift gene expression to grow taller, faster and even orient their leaves differently.  Unfortunately they short change root growth in that case and it can lead to more drought susceptibility later.

You Want to Talk About Changes in Gene Expression!

Plants are pretty remarkable.  They started out complex, and we have modified them a great deal by selection and breeding over millennia.  What we now know as maize or corn was a wild plant called teosinte in the mountains of Mexico 12,000 or so years ago (see the little heads of teosinte next to the knife in the picture above).  People selected it and progressively modified it with no real knowledge of what they were doing and turned it into what we would call “Indian Corn.”  More intentional breeding took that and turned it into something vastly more productive and adapted to different environments all over the globe.  We are just now beginning to breed corn with the tools to know how the changes happen (genomics, proteomics, marker assisted breeding).  Lately, we’ve made a few very small changes in genes with transgenics.  Any potential “changes in gene expression” from that look pretty insignificant against the background of the massive changes we’ve already made and the influence of the environment.

Cornfield Image from Lars Plougmann’s Photostream

Maize and teosinte image photo by Hugh Iltis (Creative Commons)

About the Author

Born in Denver, now living near San Diego. Agricultural scientist for 30+ years with a Ph.D. in Plant Pathology. Have worked for Colorado State University, DuPont and Mycogen and for the last 13 years consulting for all sorts or companies, universities and grower groups. Experience in biological control, natural products, synthetic chemicals, genetics, GMOs and agronomic practices. Have given multiple invited talks on the interaction between agriculture and climate change (both ways)


  • If you want to eat GMO food more power to you. I don’t want to eat it or support it’s growth. Foods should be labeled so that people know what they are eating. Most chemicals that are being used these days haven’t passed any sort of testing to prove that they are safe. We are all guinea pigs in this experiment.

    We need a sample of people that can avoid these foods and considering the rising birth defects and chemical imbalances in people it is obvious to see that we need to label things to find the culprit. Here’s an article you should read. I’ll be more than happy to inherit the earth from risk takers such as yourself but my safety and future are put at risk by your recklessness. Labeling and tracking foods is crucially important for our future.

    This is no different from cigarette smokers. Second hand smoke kills but cigarette smokers will continue to pollute my lungs until laws are made to stop them. Just like smokers you are addicted to cheap foods and products and blindly ignoring history which is repeating itself. I remember hearing about how good Cigarettes, Coke, DDT, Heroin, and many other things were for your body and health. It’s funny how they are always right.

    Monsanto steals farms and ruins natural diversity. By polluting farms with their seeds and pollen they then claim that the owner has patented Monsanto property and sues them. What kind of society do we live in where this can happen continuously. We are no longer protected by our government and your fueling stupidity with your article.

    Nature has found ways to adapt and grow. Seeds can be cultivated and saved by selecting traits you would like to see in future years. They don’t require heavy amounts of pesticides because they adapt naturally. Genetically altered seeds may only “look” slightly different but are incredibly different(Thanks for the spin you remind me of corporate commercials) Nature would never create the seeds that Monsanto is now creating. It’s kinda funny how many countries are now banning GMO foods. Too bad America can’t get behind it. Monsanto makes too much money. Capitalism is the perfect spot for corruption to grow.

  • M, Davis;

    I'm not critical of nature for biodiversity, I'm trying to put GMOs into perspective vs natural biodiversity, and man-made biodiversity. By both measures it is a tiny modification of gene expression.

    There is no secret society here except that to really understand it you need some background in molecular biology. I have no real understanding of how microchips work. Does that make Intel et al a secret society?

    You seem to be worried that your genes are being manipulated. I can't imagine a mechanism by which that is happening except by natural mutations that are occurring in our body.

    Actually, it can take a long time for people to realize that fully natural things are toxic. Mycotoxins including the most potent natural carcinogen known, aflatoxin, were only first recognized in the 1960s but had been an issue in the food supply for centuries.

    I know a lot of farmers who would dispute your claim that GMOs only benefit Monsanto and similar companies.If you don't believe that they have bought this technology on a huge scale without benefit for them, then you are suggesting that these are a bunch of idiots. I wish you could meet some of them. It would change your opinion.

    Please tell me an example of science to help the world that you adore. I'm sure it is not hard to find one.

    If you want to demand the right to know every detail about your food, then I suggest that you must be willing to pay for some enormous costs for segregation, traceability etc. If you think that Organic gives you this assurance, then I suggest that you investigate how solid Organic certification is for food ingredients etc sourced from China and Central America.

    It is fine if you want GMOs "off your plate." Go for it. The rest of us will move on.

  • Your little article sounds like you are criticizing Nature for for giving us biodiversity! Total spin!

    You response to Tim is condescending. Funny how scientists try to keep us so called "Luddites" in the dark. Where's labeling of GMOs?

    This secret society can be likened to the early days of Bible study when only the kings and scribes were allowed to know the contents, so that the common man could be controlled…and manipulated. Except this time our genes, and animal genes, are being man. It is natural that genes are manipulated by nature, but somehow, you've turned that into a negative. Do you think we are all stupid?

    You state the obvious in your article, yet a

    as for your 1000 year statement, you deliberately overlooking the obvious. It doesn't take 1000 years to find out if a plant in nature is poisonous. A person will take a bite of a new fruit or veg and if there are no ill effects, will try a little more. However, with your GMOs (some of you) will trust they are healthy, and clean your plate – and that immediate, on a global scale, without any sort of trial period. Damage from GMOs is not being studied extensively, (or at least reported) so how does one know if there is danger? There are a few independent studies out there and the results are frightening. But I'm sure you know that and are ignoring the facts.

    Spin! Spin! Spin!

    The only real advantage of GMOs is to Monsanto and like biotech companies. Oh, what a different world it would be if they were doing it for health purposes instead corporate $$$s.

    All that said, I adore science if it is put to a usage that will help the world. GMOs may have their place, but it is definitely not on my plate – not even through GMO fed animals – and I demand the right to know if it is in my food or if my food had eaten it!

  • Hybrid breading is MUCH different from gene manipulation. Making plants that produce there own pesticides and making them herbicide resistant is the problem without long range testing. 14 years is not enough. Factory farming sterilizes and poisons the soil. Also, as important, is the dreadful business practices of the GMO producers like Monsanto. They are monopolizing the food market, and suing small farmers out of their farms. 200,000 Indian farmers have committed suicide due to their practices. Forget the “we need to feed the world,” argument. 90% of GMO grains are converted to bio-fuels, and old growth forests are being cut down in record numbers to convert to this un-sustainable practice. Look at what happened to Cuba. While the USSR was supporting them they grew on large state owned factory farms, growing conventionally with chemical fertilizers. pesticides, and herbicides; very petroleum intensive. They still could not feed themselves. When The USSR dissolved and they were forced into an organic alternative, everything changed for the better. They are now both energy and food independent, and have greater health than we do. Their sterile and poisoned soil, from years of factory farming has been restored. Their whole physical structure has been changed to a “live close to where you work or study” society, cutting down the need for fossil fuels. This is the grand experiment showing how organic agriculture is FAR superior to any GMO based factory farm. A 3 million people forced experiment. Check it out:

  • Tim,

    You seem to be repeating a series of myths you got off the internet from anti GMO sites. They are all about as valid as the "death panel" myth about health care reform. Your idea that soil is made sterile by modern farming is just wrong. The only soils that are sterilized are for certain specialty crops like strawberries. Even that does not last long at all – "nature abhors a vacuume" and they are rapidly recolonized by all sorts of things. Your 90% conversion number for biofuels is way off – actually most of it goes to animal feed. The cotton does not go to fuel nor does the canola.

    Yes, hybrid breeding (not breading) is much different from genetic engineering. It involves uncontrolled changes in thousands of genes at once. We still don't fully understand why hybrid vigor occurs. That does not mean it is dangerous, but if you think 14 years isn't enough to know in the case of a small, known genetic change, then 1000 years couldn't be enough to know if hybrid breeding is safe.

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