Researchers genetically alter wheat to make it nearly free of gluten

Phys.org ^ | 11-27-2012 | Staff

[Red Badger]

—An international team of researchers has succeeded in genetically altering wheat seeds to prevent the production of gluten in subsequent plants. The effort focused, the team writes in their paper published in the Proceedings of the National Academy of Sciences, on disabling the enzyme responsible for activating genes responsible for the development of gluten protein.

The research team is part of an effort by many groups to solve the problem of celiac disease, which is an autoimmune disorder triggered by gluten. The current treatment for patients with the disorder is to instruct them to avoid foods with gluten in it. The problem with that approach of course is that it leads to a difficult to maintain, severely restricted diet.

Recent research has centered around trying to isolate certain types of grains that don't produce gluten and switching over to them. That effort has run into trouble however as thus far none have been found that are safe for celiac patients. Another approach has been to try to develop a substance that could be added to the diet to aid in the digestion of gluten. But such efforts on that front have failed as well.

This latest research has taken a different approach: altering current grains to cause them to not produce gluten in the first place. To alter samples of wheat seeds, the researchers focused on the enzyme DEMETER which is responsible for activating a group of genes that result in the production of gluten. Using several genetic engineering techniques they managed to suppress the DENMETER enzyme by 85.6 percent which resulted in a 76.4 percent reduction of gluten in the seeds that were produced. The researchers acknowledge that more work lies ahead to reach the ultimate goal of removing gluten from the wheat seeds altogether, but they say their results so far have given them confidence that they will be able to soon meet their objective. They also note that flour made with the seeds they've altered thus far appears to still be suitable for making bread. They also add that even as their attempts move forward to remove gluten altogether from grains, other research will commence to determine if such grains will allow for use in foods by those that suffer from celiac disease, with tests being conducted on mice and gluten sensitive apes.

More information:

Structural genes of wheat and barley 5-methylcytosine DNA glycosylases and their potential applications for human health, PNAS, Published online before print November 26, 2012, doi: 10.1073/pnas.1217927109 Abstract Wheat supplies about 20% of the total food calories consumed worldwide and is a national staple in many countries. Besides being a key source of plant proteins, it is also a major cause of many diet-induced health issues, especially celiac disease.

The only effective treatment for this disease is a total gluten-free diet. The present report describes an effort to develop a natural dietary therapy for this disorder by transcriptional suppression of wheat DEMETER (DME) homeologs using RNA interference. DME encodes a 5-methylcytosine DNA glycosylase responsible for transcriptional derepression of gliadins and low-molecular-weight glutenins (LMWgs) by active demethylation of their promoters in the wheat endosperm. Previous research has demonstrated these proteins to be the major source of immunogenic epitopes.

In this research, barley and wheat DME genes were cloned and localized on the syntenous chromosomes. Nucleotide diversity among DME homeologs was studied and used for their virtual transcript profiling. Functional conservation of DME enzyme was confirmed by comparing the motif and domain structure within and across the plant kingdom. Presence and absence of CpG islands in prolamin gene sequences was studied as a hallmark of hypo- and hypermethylation, respectively. Finally the epigenetic influence of DME silencing on accumulation of LMWgs and gliadins was studied using 20 transformants expressing hairpin RNA in their endosperm. These transformants showed up to 85.6% suppression in DME transcript abundance and up to 76.4% reduction in the amount of immunogenic prolamins, demonstrating the possibility of developing wheat varieties compatible for the celiac patients.

Journal reference: Proceedings of the National Academy of Sciences

[muawiyah]

Missed this one back in november ~ yes, you are correct, what is wrong here is human DNA. Wheat has not been a universal staple ~ it isn't grown everywhere, and although widely available, it isn't available everywhere.

Not every variety of human can get along with wheat. The number usually tossed out is 1% for Europeans. Many other groups we just don't know about because they don't consume wheat and have no idea what it is. There are other grain allergies. For example 10% of Japanese can't get along with rice!

Then there are Americans! We got everybody here, but not all in equal measure. 3.5% (app) of adult Americans are intolerant of wheat according to the Celiac researchers at University of Maryland. Virtually no black people have that problem, and then there's an equally large number who haven't been studied because they use corn as their primary staple ~ (raises hand).

Part of the reason for the increased level of gluten intolerance arises from the 'founder effect' ~ and we have that in spades. The Scandinavian Sa'ami people appear to have been isolated from the rests of Europe for a good 18,000 years ~ they've become a genetic isolate and they retain many genetic components common in the European Cro-Magnon ancestry that arrived 35,000 years ago.

The Cro-Magnon hunter gatherers, and the Sa'ami up to 1,000 years ago, simply had no contact with wheat. We do know humans have to genetically adapt around a new food like wheat ~ and that's not yet happened with the Sa'ami.

Thanks to the Swedish Empire the Sapma where the Sa'ami live, was almost depopulated as they were shipped to America! Being among the first European settlers in this country they had more time to adapt and spread and become a far larger percentage of the new American nation than would otherwise be expected.

3.5% means there are at least 9,000,000 folks here with the genes for Celiac ~ but not all people with those genes express the disease in their younger years. On the other hand, that means the Sa'ami ~ or part-Sa'ami ~ people in this country are a large minority ethnic group which is virtually invisible due to the large percentage of blonds among them.