Researchers Reconstruct Genome of Wild Wheat – Sci-News.com

An international research team led by Tel Aviv University scientist Dr. Assaf Distelfeld has reconstructed the genome of the wild wheat Triticum turgidum, the original form of nearly all the domesticated wheat in the world.

Triticum turgidum. Image credit: Stan Shebs / CC BY-SA 3.0.

Wheat is one of the founder crops that likely drove the Neolithic transition to agrarian societies in the Fertile Crescent more than 10,000 years ago.

Its domestication caused a shift in traits, which mostly relate to seed dormancy, spike morphology, and grain development.

For example, while the spikes of wild wheat shatter at maturity, all domesticated wheat spikes remain intact, which enables easier harvest.

From a biological and historical viewpoint, we have created a time tunnel we can use to examine wheat from before the origins of agriculture, Dr. Distelfeld said.

To reconstruct the 14 chromosomes of Triticum turgidum, Dr. Distelfeld and co-authors used 3D genetic sequencing data and software.

The wheat genome is much more complex than most of the other crops and has a genome three times the size of a human genome, said co-author Dr. Gil Ronen, CEO of NRGene Ltd, Israel.

Still, the computational technology we developed has allowed us to quickly assemble the very large and complex genome found in wild wheats 14 chromosomes, to a standard never achieved before in genomic studies.

Our ability to generate the wild wheat genome sequence so rapidly is a huge step forward in genomic research, added co-author Dr. Curtis Pozniak, from the University of Saskatchewan.

Wheat accounts for almost 20% of the calories humans consume worldwide, so a strong focus on improving the yield and quality of wheat is essential for our future food supply.

In order to understand genetic changes underlying the evolutionary transition to a non-shattering state, the researchers compared genes responsible for shattering in domesticated wheat to the corresponding genes in wild wheat.

They identified two clusters of genes in domesticated wheat that have lost their function.

When they engineered strains of wheat with one of these gene clusters restored, the wheat exhibited unique spikes where the upper part was brittle and the lower part was not brittle.

These results suggest that the two gene clusters play a part in the transforming the brittle qualities of wild wheat.

Our comparison to modern wheat has enabled us to identify the precise genes that allowed domestication the transition from wheat grown in the wild to modern day varieties, Dr. Distelfeld said.

While the seeds of wild wheat readily fall off the plant and scatter, a change in two genes meant that in domesticated wheat, the seeds remained attached to the stalk; it is this trait that enabled humans to harvest wheat.

This research is a synergistic partnership among public and private entities, said co-author Dr. Daniel Chamovitz, of Tel Aviv University.

Ultimately, this research will have a significant impact on global food security.

The research is published in the journal Science.

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Raz Avni et al. 2017. Wild emmer genome architecture and diversity elucidate wheat evolution and domestication. Science 357 (6346): 93-97; doi: 10.1126/science.aan0032

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Researchers Reconstruct Genome of Wild Wheat - Sci-News.com