by Guest Posts on 16 May 2012 Crop plants with DNA deletions are not GMOs
by Sophien Kamoun and Eric Ward
 Bacterial blight caused by Xanthomonas can result in up to 50% yield reduction in severe epidemics. Image from the International Rice Research Institute. In 2007, Sebastian Schornack, then a freshly minted Ph.D. student from the laboratories of Thomas Lahaye and Ulla Bonas at the Martin-Luther-University Halle-Wittenberg, was fastidiously carrying out follow-up experiments to his thesis work. For the past few years he had been studying how the bacterium Xanthomonas infects its plant hosts. Specifically, he was interested in a class of “effector” proteins, called transcription activator-like (TAL) effectors, that the bacterium delivers to the nuclei of host cells to alter plant gene expression.
Ever since their discovery in the late 1980s, the unusual structure of these effector proteins has intrigued plant microbiologists. TAL effectors contain many near-perfect repeats 34 amino acids in length with two hypervariable residues, but the biological meaning of this peculiar modular structure was unknown. At the time Schornack was finishing his thesis, TAL effectors had just been discovered to bind specific DNA sequences in the genomes of their host plants, where they activated expression of host genes thought to favour colonization by the pathogen. While comparing the identity of the hypervariable amino acids in the repeats of particular TAL effectors with the corresponding DNA sequence of their binding sites, Schornack experienced a flash of insight, and noticed a defining pattern [Schornack].
Following discussions with Jens Boch and experimental work with their colleagues at Halle University, it became evident that, indeed, a “code” built into the TAL effector proteins determines their DNA binding specificity [Boch]. Not long after that, across the Atlantic, another Ph.D. student Matt Moscou, working with Adam Bogdanove at Iowa State University, independently reached a similar conclusion using clever computational analyses of TAL effector-induced expression changes in rice plants [Moscou].
Both teams immediately grasped the impact of their discoveries – synthetic TAL effectors could be custom designed to bind any target DNA sequence. Such a technological breakthrough would have far reaching implications in biotechnology.
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by Frank N. Foode™ on 15 May 2012 Hi everyone, Frank N. Foode™ here. I was hanging out, smelling some Tulips in Madison, WI, and none other than Dr. Michael Grusak stopped by from the Baylor College of Medicine to give a seminar on his nutritional research into Golden Rice. I was so excited I ended up live tweeting the whole thing on #mikegrusak! For those who aren’t big on the whole twitter thing – have no fear – I Storified it and added in some pictures and extra links, too. Now a seminar that reached dozens can now be experienced by hundreds, or thousands. (Isn’t technology wonderful?)
So does a genetically engineered variety of rice made by hundreds have the potential to help thousands, or maybe millions? Check this out!
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In England, there is an important experiment underway. A research group at the Rothamsted Research station in Harpenden, is testing a variety of wheat that has been genetically engineered to scare away aphid pests. If successful, the experiment could demonstrate the effectiveness of a novel, environmentally-friendly way to manage pests. However, a protest group is threatening the ability of the researchers to continue their project, and there have been a lot of claims made about the research. To help shed some light on this experiment, I interviewed Dr. Gia Aradottir, a biologist who is involved in the project.
KJHvM: Can you tell us a bit about yourself and how you came to work at Rothamsted and on this project? What is your role in the project?
 GA: I’m the newest member of the GM wheat team, I joined the E-β-farnesene project a year and a half ago. I did my PhD jointly at Rothamsted Research and Imperial College London where my work focused on the giant willow aphid (Tuberolachnus salignus), chemical ecology and population genetics. My PhD project was partly supervised by the chemical ecology group and when I had the opportunity to join, I jumped at the chance. We have a fantastic team of people working together, and a lot of interdisciplinary possibilities with the different departments within Rothamsted and the wider scientific community. We work on a number of projects, and my contribution to this particular project has been insect behavioural studies and analysis of the volatile profiles of the GM wheat.
KJHvM: Can you explain the experiment for our readers? What is the nature of the trait, how it works, and how it could change wheat production if it is successful? How important is this research?
GA: I like to say that we are helping plants to protect themselves against insects.
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The Frustrating Lot Of The American Sweet Corn Grower
We Americans love sweet corn – our uniquely national vegetable. We consume ~9 lbs of sweet corn per person per year (see how that compares to other vegetables in the graph above). The farmers that grow this crop for us do so on a much more local basis than for most fruit or vegetable crops. There are significant sweet corn acres in 24 states and a total of >260,000 acres nation-wide for the fresh market and >300,000 for canned and frozen corn (see graph below). Sweet corn can be difficult to grow for many reasons, and is often sprayed with insecticides. A biotech solution to this problem exists, but it is under-utilized, in part, due to campaigns by anti-GMO activists. In the end, the people most hurt by this are the American sweet corn growers.
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