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dimanche, 19 février 2017

MOLECULAR SCISSORS

NON-TRANSGENIC CORN, RICE AND MAIZE RESITANT TO MILDEW. NEXT…. THE VINE?


Claude Gilois

In an article published at the end of August 2016, I was describing a new revolutionary technique that you be applied to improve the resistance of the vine. I was not aware that a Chinese geneticist, Goa Gaixia, was working on modification of the genome of rice, corn and maize to improve their resistance and this a brought the prestigious American Science magazine Nature to select her among the best of a dozen of Chinese top scientists. Admittedly, she did not work with the vine, but her work has led to creation of new varieties of rice, corn and maize resistant to mildew, and with this discovery, we are not too far from our beloved Vitis vinifera, which is battling, more and more against a variety of crippling diseases.

 

ciseaux-moleculaire_orig.jpg

 

Read the complete article on this new technology

 

Reminder: The discovery of a fourth generation of these enzymes called CRISPR-Cas9[1] has constituted a true innovation. The only thing that is required is the RNA {2) guide to identify where the modification has to be made on the genome and it is very easy to produce these RNA guides using robots. When the RNA guide finds its target on the genome, Cas9 cuts the DNA. The genome can then modify as required by removing, inserting or modifying a gene (mutation or correction of a mutation). Cas9 can also be used within the epigenetics’ [3] environment of the gene and, if coupled with the correct enzyme, it can amplify or tone down the activity of the gene. What is revolutionary is that this technique works with all living organisms (plants, mammals, yeasts and amphibians).

 

What has been achieved is quite a feast as a corn is far more complex plant than a vine. It is a polyploïde plant and each cell contains 3 genomes. She had to isolate and neutralise the appropriate gene in the 3 genomes. And the icing on the cake, the new variety is not in the true sense of the term a transgene as no external gene was added to the DNA sequence. If you were to carry out a DNA sequencing on the new plant, it would be impossible to detect any difference with a non modify plant. All I did says Goa Gaixia: ‘ was to inactivate the gene which inhibited the immune response to the corn to mildew”. It is very much like mutations that have occurred naturally for millions of years within the animal and plant kingdom. That may be so, but how will the authorities view these new seeds? Will they be classified as GMO or not? The European Union was supposed to give its verdict in 2016. but we are still waiting for it and if it takes 25 years as it has taken the Union to start tackling endocrine disrupters, there could be a very long legal vacuum. If the EU classifies the products of this new technology as chemical substances, they will fall under the ‘REACh’[4] program of the EU, which is attempting to control the diffusion of all chemical substances more tightly within the Union. The US ministry of agriculture has not considered these new modify seeds as GMO, but other federal bodies have yet to rule of this. In China, where GMO cultures are forbidden, we eagerly await the position of the authorities on the new plants created with this new technology and which have propelled one of its scientists to the forefront of research in this domain.

Patenting of the discovery is also an issue that has significantly evolved since last August. Two patents had been filed by two universities, the Californian Berkeley and the prestigious MIT (Massachusetts Institute of Technology). The later has recently won a significant battle in court, but the war is certainly not over. However, both universities have taken the view that the discovery would be made available free of charge to the academic world.

 

[1] ‘Clustered Regularly Interspaced Short Palindromic Repeats’

[2] Its primary function is to convert the information stored in DNA into proteins.

 

[3] Epigenetic: the different ways that a gene can manifest itself without the sequence of the DNA being changed. A gene can have a different ‘strength’ of expression from one plant or from one individual to another.

[4] Control system of the European Union for chemical substances which covers fields such as genetic toxicity, toxicity by repeated administration, toxicity on the foetus, toxicity on reproduction, carcinogenic effects, long- term aquatic toxicity, biodegradation and bioaccumulation.

 

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