First step taken toward epigenetically modified cotton

Upland cotton (right) evolved via the hybridization of two ancestral species, one similar to G. raimondii (left) along with one similar to G. arboreum (middle). Selection along with domestication yielded longer, higher quality fibers than either ancestor. Credit: Chen Laboratory/Univ. of Texas at Austin

With prices down along with weather patterns unpredictable, these are tough times for America’s cotton farmers, yet brand new research led by Z. Jeffrey Chen at The University of Texas at Austin might offer a break for the industry. He along that has a team have taken the first step toward a brand new way of breeding heartier, more productive cotton through a process called epigenetic modification.

In recent decades, scientists have discovered which many traits in living things are controlled not just by their genetics—what’s written within the code of their DNA—yet also by processes outside their DNA which determine whether, when along with how much the genes are expressed, known as epigenetics. This specific opens up the possibility of entirely brand new ways to breed plants along with animals. By selectively turning gene expression on along with off, breeders could create brand new varieties without altering the genes.

In This specific latest study, the researchers identified more than 500 genes which are epigenetically modified between wild cotton varieties along with domesticated cotton, some of which are known to relate to agronomic along with domestication traits. This specific information could aid selection for the kinds of traits which breeders want to alter, like fiber yield or resistance to drought, heat or pests. For example, varieties of wild cotton might harbor genes which help them respond better to drought, yet have been epigenetically silenced in domesticated cotton.

“This specific understanding will allow us to supplement genetic breeding with epigenetic breeding,” says Chen, the D. J. Sibley Centennial Professor of Plant Molecular Genetics within the Department of Molecular Biosciences. “Since we know currently how epigenetic improvements affect flowering along with stress responses, you could reactivate stress-responsive genes in domesticated cotton.”

In a study published today within the journal Genome Biology, Chen along with his colleagues at Texas A&M University along with Nanjing Agricultural University in China report they produced a “methylome”—a list of genes along with genetic elements which have been switched on or off through a natural process called DNA methylation. A methylome provides important clues for biotechnology firms which want to adapt crops through epigenetic modification. This specific methylome covers the most widely grown form of cotton, known as Upland or American cotton; its cousin, Pima or Egyptian cotton; along with their wild relatives, while showing how these plants changed over more than a million years.

“Knowing how the methylome changed during evolution along with domestication will help bring This specific technology one step closer to reality,” says Chen.

A partly harvested cotton field. Credit: Kimberly Vardeman

Cotton can be the top fiber crop grown within the globe, with more than 150 countries involved in cotton export along with import. Annual business revenue stimulated by cotton within the U.S. economy exceeds $100 billion, creating which America’s No. 1 value-added crop.

The researchers discovered improvements in DNA methylation occurred as wild varieties combined to form hybrids, the hybrids adapted to improvements in their environment along with finally, humans domesticated them. One key finding can be which the change which allowed cotton to go via a plant adapted to grow only within the tropics to one which grows in many parts of the globe was not a genetic change, yet an epigenetic one.

The researchers found which wild cotton contains a methylated gene which prevents which via flowering when daylight hours are long—as they are within the summer in many places, including the United States along with China. In domesticated cotton, the same gene lost This specific methylation, allowing the gene to be expressed, an epigenetic change which allowed cotton to go global.

Chen says modern breeders can modify gene methylation with chemicals or through modified gene-editing technologies such as CRISPR/Cas9. These methods could allow breeders to make targeted improvements to a plant’s epigenome along with create brand new breeds with increased traits. Epigenetic breeding could be applied not just to cotton yet to many different major crops such as wheat, canola, coffee, potatoes, bananas along with corn.

The brand new research builds on the most complete genetic sequence map of American (or Upland) cotton to date, which was also developed by Chen along with his collaborators in 2015.

Earlier research traced the origins of domesticated cotton back 1.5 million years, when two different wild species formed a hybrid which eventually gave rise to modern Upland along with Pima cotton species. Chen along with his team found which the DNA methylation improvements in a similar hybrid made today were shared with those in wild along with cultivated cottons, suggesting which these improvements have persisted through evolution, selection along with domestication. which’s not bad news for breeders who want to be sure which improvements they make today won’t quickly fade away in future generations.

Explore further:
Genetic road map may bring about better cotton crops

More information:
Qingxin Song et al, Epigenomic along with functional analyses reveal roles of epialleles within the loss of photoperiod sensitivity during domestication of allotetraploid cottons, Genome Biology (2017). DOI: 10.1186/s13059-017-1229-8

Journal reference:
Genome Biology

Provided by:
University of Texas at Austin

First step taken toward epigenetically modified cotton

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