March 13, 2012

Making Wheat Salt Tolerant

Australian scientists have bred a variety of durum wheat that can grow up to 25% better in salty soils.

Scientists from the CSIRO Plant Industry discovered a salt tolerant gene and, using non-GM breeding techniques, implemented this gene into a commercial durum wheat. The field tests of this crop show remarkable results. Researchers from the University of Adelaide´s Waite Research Institute are leading the effort to understand how this specific gene lends the wheat the ability to withstand saline conditions.

From the research in the lab to the implementation in the field, this is the first research of its kind to explain and identify the salt tolerance of an agricultural crop.

The senior author of the paper is Dr. Matthew Gilliham from the University´s Waite Research Institute and the ARC Centre of Excellence in Plant Energy Biology. Lead authors are CSIRO Plant Industry scientists Dr. Rana Munns and Dr Richard James and University of Adelaide student Bo Xu. Together, the team posted their results in the journal Nature Biotechnology.

“This work is significant as salinity already affects over 20% of the world´s agricultural soils, and salinity poses an increasing threat to food production due to climate change,” Dr. Munns says.

Australia in particular is facing its own severe issues of dry land salinity. However, the researchers know that their findings will have global benefit.

Dr. Gilliham says: “Salinity is a particular issue in the prime wheat-growing areas of Australia, the world´s second-largest wheat exporter after the United States. With global population estimated to reach nine billion by 2050, and the demand for food expected to rise by 100% in this time, salt-tolerant crops will be an important tool to ensure future food security.”

Durum wheat is often used for making foodstuffs like pasta and couscous. The effects of breeding and domestication has created fewer species of the wheat, thereby making it more susceptible to environmental stresses, such as dry land salinity.

While the gene pool for durum wheat is shrinking, researchers decided to take a look back at some of durum´s ancestors for some genetic insights. What they found was a significant source for genetic traits, including a trait for tolerance to salinity.

“Salty soils are a major problem because if sodium starts to build up in the leaves it will affect important processes such as photosynthesis, which is critical to the plant´s success,” Dr. Gilliham says.

“The salt-tolerant gene (known as TmHKT1;5-A) works by excluding sodium from the leaves. It produces a protein that removes the sodium from the cells lining the xylem, which are the ℠pipes´ plants use to move water from their roots to their leaves,” he says.

Field trials of the new, non-GM versions of durum wheat were lead by Dr James. This study is the first to every confirm a salt tolerant gene in actual saline soils as opposed to testing in a greenhouse.

The trials were conducted at sites all over Australia, as well as a commercial farm in New South Wales.

The farmers and researchers were quite pleased with their results. Dr. James said in their paper “Under standard conditions, the wheat containing the salt-tolerance gene performed the same in the field as durum that did not have the gene. But under salty conditions, it outperformed its durum wheat parent, with increased yields of up to 25%”.

The researchers are taking what they have learned from durum wheat and are now trying to breed a version of salt-tolerant bread wheat.


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