Tag: genetically modified crops

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Seminar series highlights: Fiona Doohan

wheat

As mentioned previously on the blog, Andrew Jackson and I started a new module this year called “Research Comprehension”. The module revolves around our Evolutionary Biology and Ecology seminar series and the continuous assessment for the module is in the form of blog posts discussing these seminars. We posted a selection of these earlier in the term, but now that the students have had their final degree marks we wanted to post the blogs with the best marks. This means there are more blog posts for some seminars than for others, though we’ve avoided reposting anything we’ve posted previously. We hope you enjoy reading them, and of course congratulations to all the students of the class of 2014! – Natalie

Here are Yutaka Kumagai and Cormac Murphy’s views on Dr. Fiona Doohan‘s seminar, “Plant-Microbe interactions – the good, the bad and the ugly”.

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Food security: A game changer for GMOs?

Yutaka Kumagai


The subject of genetic modification has always carried with it a certain level ethical ambiguity in the eyes of the wider public. While quite a significant proportion of the blame for this may be down to misinformation and ignorance, it may also be contributed to the somewhat shady operations of large corporations such as Monsanto. It is inevitably the more shocking or controversial stories that capture the imaginations of the public, and the David and Goliath legal battles between farmers and corporations do not fail to grab attention. Anti-GMO activist groups are also extremely vocal in their fight for organic produce, and many of the articles that may be sourced online are heavily biased in their favour.

On a national level, public opinion is clearly against the notion of genetically engineered organisms, a simple google search of ‘Ireland GMO’ returns multiple hits from anti-GMO sites. Yet while Irish consumers may not approve of GM, it is obvious that many also do not understand the concept. A certain amount of the blame for this ignorance surely lies with the lack of dialogue surrounding the topic, with most of the information broadcast being anti-GMO, without providing much of an explanation. This may even be seen in large scale shops such as Marks & Spencers lauding their wares as non-GM.

However, the benefits of many GM foods are such that surely a system of control would be more profitable than outright ban. In a recent seminar, Dr. Fiona Doohan, a senior lecturer at UCD, gave an insight into the research being undertaken by her team on disease resistance in cereal crops. Specifically, her works focuses on the infection of wheat  and barley crops by Fusarium graminearum and F. culmorum, which are known causes of Fusarium Head Blight (FHB) disease. This causes bleaching of cereal grains, and is harmful to plants and animals. The main toxin produced during infection is deoxynivalenol (DON), which facilitates FHB, and may be attributed as the cause of many of the observable effects. By observing variance in wheat response to DON, Doohan was able to find a resistant genotype. Unfortunately, this resistant genotype carried with it its own set of negative traits, preventing it from use as an effective cash crop. As such, Doohan attempted to identify the specific genes associated with resistance. Expression levels of DON-resistant wheat genes were analysed through the use of microarray testing, with results verified through RT-PCR analysis. This allowed for the identification on orphan (lineage specific) genes involved in the defence pathway activated by DON to be identified. With further research, it will hopefully be possible for this pathogen resistance to be conferred to susceptible wheat strains.

It would be difficult to colour such a development in a bad light, especially considering that wheat is one of the most produced cereal crops in the world. So why is public opinion so against GMO? All GMO food products must pass rigorous testing by the WHO, with continuous assessment taking place once a product is released to the market. While certain GM foods, such as golden rice, do make their way into the public ‘good books’, even these success stories are not as widely known as they ought to be. Yet, it can only be hoped that the current research being undertaken by Doohan, and those like her, will turn the tide in this war of misinformation.

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Give us this day our daily bread

Cormac Murphy


Wheat and its by-products have been such an integral part of human livelihoods for so long they’ve become religious artefacts. They are everywhere, just ask a despairing coeliac. But for as long as we’ve been cultivating wheat, our health has been intertwined with that of the crop. Poor weather, mycological diseases or trampling could take both the income and vital nutrition from a family. And if an infected stalk was reaped and processed into food, it could pose a real threat to the health and sanity of a community. Some classic examples are the cases of ergot poisoning that lead to mass hysteria and witch burnings across Europe in the middle ages. Today with wheat representing the second largest source of calories for all mankind, the health of our wheat crop has never been more important.

And it’s up to people like Fiona Doohan, Director of the UCD Earth Institute to cultivate strains of wheat that can produce enough to meet the need of a hungry word (and economy) that are resistant to these harmful pathogens. Dr. Doohan’s lab focused on the fungus Fusarium graminearum, which causes fusarium head blight  (fhb) a disease that devastates wheat and barley resulting in billions of dollars loss in crops annually. Dr. Doohan looks at the actions of the fungus focusing on one of the main toxins it produces, deoxynivalenol (DON) also charmingly known as vomitoxin. DOM interferes with protein synthesis and when applied by itself to the wheat heads  produced the bleaching characteristic of fhb. In low levels DON has been found to prevent cell death, whereas at high levels DOM causes it. This facilitates the switch from vitotrophic to necrotrophic which is a key part of the disease’s progression and spread. Dr. Doohan looked at 2 cultivars of wheat; Remus which was susceptible to DOM but produces an economically viable crop, and CM 82036 which wile being a less viable source of income is resistant to DON.

Both were treated with DOM. After 4 hours the plants were observed and RNA samples  and run through a custom microarray were taken from both plants, this was repeated after 24 hrs. The DON was seen to have a greater effect after 24hrs in the Remus both visibly and in terms of disrupting protein synthesis. In the resistant strain the majority of the proteins that seem to be produced in response to the toxin were “unclassified” the products of “orphan genes”. Orphan genes are genes with very specific lineages that we currently have very little information on in databases. Doohan’s team found that these particular orphans seemed to be linked to stress responses in the plant. There was also evidence that they were fast evolving, with even close phylogenic relatives baring genes with as little as a 50% match. They appeared to be more toxin specific than tissue specific, arising at the points where DON was introduced. These seem like the key to DON resistance and potentially the key to transferring that resistance. A yeast 2 hybrid screen was then used to examine the interactions of these orphan proteins with other proteins known to be active in stress resistance. In these tests a related mycological toxin T-2 was used on the yeast as yeast is highly DON resistant. Just to drive home the seriousness of these toxins T-2 is the key ingredient in now banned biological weapon known as “Yellow rain”. The results of these tests indicated that the orphans are involved in the activation of the SnRK1 stress resistance pathway thought how it interacts remains unknown.

These experiments have given us a glimpse at a potential new tool to protect the food security of the world. But with so little known about the genes involved, a lot of work still needs to be done. Some wheat genomes have recently been sequenced and the information that can be gathered from them may yet shed light on our orphans. As with any GM organism, particularly one that’s intended for human consumption, there must be a great understanding of exactly how these changes will affect the makeup of these plants.

Image: Wikicommons

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Seminar Series: Fiona Doohan, University College Dublin

wheat field

Part of our series of posts by final-year undergraduate students for their Research Comprehension module. Students write blogs inspired by guest lecturers in our Evolutionary Biology and Ecology seminar series in the School of Natural Sciences.

This week, views from Gina McLoughlin and Joanna Mullen on Fiona Doohan’s seminar, “Plant-Microbe interactions – the good, the bad and the ugly”

GM Crops Don’t Kill

Genetically modified (GM) crops, are crops that have been modified using genetic engineering techniques to introduce certain qualities, or traits into a plant where they did not occur naturally. Usually, the genes for the desirable trait are taken from one plant and inserted into the genome of another strain of that plant. However, because of this engineering many people think that GM crops pose a serious health hazard and there seems to be a lot of tension around the topic of GM crops. This tension is mostly stemming from big companies, like Monsanto, that have nasty practice records and design GM crops for patents and profits instead of solving food problems.

However, there are many researchers out there that are working on GM crops to try and solve food problems and ensure there is enough food to feed the world’s growing population. Dr Fiona Doohan is a senior lecturer in the School of Biology and Environmental Science, UCD and she has been doing research on food security. The work that she presented to us in her lecture focused on how to enhance disease resistance in cereal crops. For her research she specifically looked at the disease Fusarium head blight (FHB) in wheat. Wheat is the second largest source of calories, after maize, yet it is produced in only a small percent of the world. FHB is a huge problem for farmers as it causes serious yield loss, which they cannot afford. It cost about €9 million per year in order to control FHB with inconsistent fungicides, so Doohan and her team are looking at a better alternative to protect these crops.

Deoxynivalenol (DON) is a mycotoxin that commonly causes the damage associated with this disease. DON is toxic to humans, animals and plants (Rocha et al., 2005) and it is very important that it doesn’t get into the food chain. DON also aids the spread of the disease in wheat heads and increases the severity of the symptoms of FHB (Bai et al., 2001). It causes bleaching of the wheat heads, alters membrane structures and causes cell death. DON also inhibits seed germination, shoot and root growth, root generation and protein synthesis (Rocha et al., 2005). Some wheat strains are resistant to DON and the genes that cause this resistance are being identified (Walter et al., 2008).

Doohan and her team wanted to look at different strains of wheat and how they reacted to DON. They put two strains of wheat up against each other, Remus and CM82036, to try to find the mechanism that allows DON resistance. Remus is the strain that is used in cultivation because it has more desirable qualities than the CM82036 strain but it is susceptible to DON. Analysis of the results was performed using DDRT-PCR and microarrays and a list of genes that could possibly be involved in DON resistance were obtained. One of the genes in this list was an orphan gene. This is a gene that had no significant homology to any known genes and it has also never been described before. Doohan and her team are doing further research into this orphan gene and hopefully it will be a lead to adding resistance to the Remus strain.

Doohan’s work may be essential to human survival if the population keeps rising and people need to start trusting research and open their minds to GM crops. Research has found that there are no adverse affects to using GM crops and they are no more unsafe than crops modified using conventional improvement techniques. They pose no additional risk to human health or to the environment. GM crops have many benefits that people overlook; they require fewer chemicals to protect them, like pest-resistant cotton. GM crops can also benefit farmers as they are more reliable and resistant to stress. Some farmers are so eager to use these crops they have had to be pirated in, for example Bt cotton was pirated into India. GM crops are also safer and more precise than mutagenesis techniques.

However, I don’t think that this evidence and these benefits are enough to change the negative opinion that society has on GM crops. I think people need to be shown that scientists, like Doohan, are now producing GM crops for the public’s benefit.  I am of the opinion that we need to change the negative attitude toward GM crops that the big companies have created and, unfortunately, this may take a very long time and a lot of effort in order to convince the consumers. It makes sense that, in order to feed 9.5 billion people on the land area that we have to grow food, with limited water, pesticides and fertilizer, and with the hugely changing climate, we need to be looking at alternative ways for human survival. Maybe GM crops are the answer.

Author: Gina McLoughlin

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Are we just clutching at straws or is there grain of hope in the battle to save our crops from destruction?

Food, we can’t live without it, we can’t live on it if it’s diseased. This is the motivation behind the work of Fiona Doohan and her team in U.C.D, who are striving to improve the security of the world’s food supply by improving the resistance of cereals such as wheat and barley to the many diseases that currently threaten their very existence. During her seminar on Friday the 22nd of November in Trinity’s Botany Lecture theatre, she outlined the main areas on which her work focuses. At the heart of which is research dedicated to plant disease control and stress resistance, as well as the potential influences of climate change and adaptation to disease.

Currently approximately 2332 million tonnes of cereals are used worldwide each year and they are considered to be a universal staple food in the diet of humans, making Fiona’s research all the more important.

During her talk she discussed one of the main diseases of interest to her group, “Fusarium Head Bight Disease” (FHB). This is a fungal disease affecting crops of Wheat and Barley, causing visible bleaching of the infected cereals early after infection.

The real trouble with this fungus however is that it produces a mycotoxin known as deoxynivalenol (DON) which leads to significantly reduced yields of the crop, and importantly can have toxic effects for animals and humans and as such infected crops are not allowed enter the food market, resulting in significant loss to revenue for farmers.

The big problem when attempting to control and prevent FHB is that fungicides have proven to have little effect on controlling it.

One of the big steps forward in tackling this fungus was the discovery of the significance the role of DON plays in spreading and maintaining the infection. Research has shown that if the DON toxin is knocked out early on the infection will be reduced and the bleaching symptoms do not develop. Also, without the DON toxin, there will be no adverse toxic effects for humans and animals thus removing the food safety concern.

Interestingly not all wheat is susceptible to FHB and DON; some exotic wheats are naturally resistant to the toxin and fungal disease. This has led to researchers asking what are the mechanisms and genes that lead to potential resistance to DON/FHB. Using gene expression studies to isolate possible genes associated with DON resistance, Doohan’s team have discovered several genes which they believe to be of interest, most noticeably one particular orphan gene.

Orphan genes are genes which are restricted to a certain lineage. They are particularly important in stress resistance, but are often ignored. It is on the role this orphan gene plays in DON resistance that Doohan’s team have centred their research efforts. Noting the importance not to tissue specificity per say but it’s specificity to DON, the orphan gene will not have an effect on mutant strains of DON. However, when artificially expressed in a non-exotic strain of wheat that would normally express DON when infected, the orphan gene has been shown to inhibit the expression of DON thus inhibiting the development of FHB.

Though these results are very encouraging, the true significance of this discovery and whether it can be applied practically to the production of crops is still waiting to be tested. Unfortunately due to strict European laws the first tests on genetically modified, field planted crops are likely to have to take place in the U.S.A. However Doohan’s research does offer a glimmer of hope in the rather bleak fungus covered problem FHB and it’s (g)rain of terror on stalks of wheat all over Europe.

Author: Joanna Mullen

Image Source: Wikimedia commons