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Monday, October 18, 2021

New haploid breeding methods for plants discovered

Slug: 100331_sc_Plants

Notes: There are [CQ]s in this article! Watch out!

Headline: New haploid breeding methods for plants discovered

Layercake: UC Davis researchers stumble upon procedure accidentally

By MEGAN MURPHY

Aggie News Writer

A discovery made by sheer chance may bring major changes to the future of plant reproduction.

Two UC Davis researchers accidentally uncovered a method for breeding plants that carry genes from only one parent. The method could greatly accelerate the time-consuming process of producing plants with desirable traits, such as pest resistance and drought tolerance.

Simon Chan[cq], assistant professor of plant biology at UC Davis and one of the authors of the paper outlining the technique, spoke of the merits of producing haploid plants [cq]. These plants contain the genes of only one parent, as opposed to diploid organisms, which possess genes from both parents and are the natural reproduction forms of plants and animals.

“Haploid breeding saves a huge amount of time,” Chan said in an e-mail interview. “Breeders can make a new true breeding variety in two generations instead of eight to 10.”

Haploid breeding is currently an expensive, complex process used on only a few select plant breeds. The newly discovered method does not require culture tissue which will significantly lower costs. Researchers expect this method to work on any plant breed.

“Some valuable species such as tomato and soybean completely lack haploid production, and we are trying to create methods for these crops,” Chan said.

Chan and his colleague, postdoctoral scholar Ravi Maruthachalam[cq], stumbled upon the method while studying CENH3, an essential protein, in the plant species Arabidopsis thaliana [cq]. They prepared an altered version of CENH3 marked with a fluorescent protein, and then bred this plant with a regular Arabidopsis.

Instead of producing the expected offspring with one mutant gene from the mother and one normal gene from the father, the plants contained only the normal gene. This occurred due to genome elimination, a process which can eliminate half of a plant’s genes when two different but related plants are bred.

Chan and Maruthachalam then stimulated these offspring to double their chromosomes, enabling them to reproduce. Though this new method is unique to the CENH3 protein, Chan hopes to achieve the same effect with other proteins.

In a press release, Chan described the breakthrough as a “game changer” for his laboratory, describing it as “opening up new research ideas, funding sources and recognition.”

Chan hopes to improve the frequency of haploid production, and then transfer this method to crops. In order to do this, the process of genome elimination must be studied in more detail.

“The precise mechanism of how and when one parental genome is eliminated needs to be determined,” Maruchathalam said in an e-mail interview. “Currently, we are collaborating with several groups to understand the nature of the mechanism of genome elimination.”

Ultimately, the researchers hope to utilize their new methods in important, widely used crops.

“We hope our method will democratize haploid breeding, especially in the developing world,” Chan said.

MEGAN MURPHY can be reached at campus@theaggie.org. XXX

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