February 17, 2015

17/02/2015: US researchers develop transgenic heat-tolerant wheat

In Kansas, USA, wheat grains begin to fill out in May and June. But if the temperatures are too high — say, above 86 degrees fahrenheit — the kernels start to shrivel.

Two Kansas State University (
K-State) researchers — Harold Trick, a professor in the Department of Plant Pathology, and Allan Fritz, a wheat breeder — are developing a transgenic wheat that would tolerate hotter temperatures during the grain development stage, CJ Online reports.


Transgenic wheat contains genetic material into which DNA from an unrelated organism has been artificially introduced. In this case, the researchers added genetic material from rice to wheat.

“It’s gene therapy for hot temperatures and yield,” Mr Trick said, adding a single gene could boost the wheat’s heat tolerance and increase yields.

Mr Trick said wheat is a cool-season grass and its grain fills out best when temperatures are between 60 and 65 degrees
fahrenheit. Potentially, a 3 percent to 4 percent yield loss occurs with every 2- to 3-degree rise in temperature.

As wheat grain begins to fill, it accumulates starch. The starch, which accounts for 75 percent to 85 percent of the grain’s dry weight, is converted from sucrose by an enzyme-protein called soluble starch synthase, or SSS.

The enzyme is sensitive to elevated temperatures. At warm temperatures, the protein starts to denature, which causes the kernels to shrivel.

“This is what we’re trying to solve,” Mr Trick said.

The researchers started looking at rice because it is a tropical plant that is grown at higher temperatures, has a grain that fills out and is genetically similar to wheat. They found a single SSS gene that provides more thermo-tolerance when added into a genome.

In essence, the added gene acts as a backup generator for grain fill, taking over starch conversion only when the original wheat protein has maxed out. The result is a steady 30 percent to 35 percent yield increase.

“To get a heat-tolerant plant, it needs a lot of different traits,” he said.

“Our (SSS) gene is just one gene in the whole mix of traits needed for heat-tolerant wheat.”

Mr Trick said he and other researchers also are looking for heat-tolerant genes in other plant species, including grapes and the black cottonwood tree of the Pacific Northwest.

Mr Trick said K-State has filed a patent to protect their technology; however, patent approvals can take several years.

“Currently, there are no genetically engineered wheat on the marketplace,” he said.

The researchers are hoping a company or other entity will become a sponsor for the genetically engineered wheat and pay for the extensive regulatory process that has to be done to ensure the product is safe before it can be commercialised and planted by Kansas farmers. Mr Trick said the process can cost “tens to hundreds of millions.”

“We want the technology in hand and validated so when genetically modified wheat is allowed to be grown, the product is there for companies who see its value,” he said.

In addition to heat-tolerant wheat, the research team also is working on a genetically engineered process that would stop wheat viruses from replicating and, in turn, result in increased yields.

Mr Trick said their research is backed by the Kansas Wheat Commission and funded by Kansas farmers through the wheat check-off, which supports research and market development.

Read more HERE.

The Global Miller
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which is published by Perendale Publishers Limited.

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