'Landmark' in wheat research

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Agriculture Canada’s Mark Jordan says cracking the wheat genome is encouraging but a lot of work on the data lies ahead. (WAYNE.GLOWACKI@FREEPRESS.MB.CA)

British scientists have decoded the genetic sequence of wheat -- one of the world's oldest and most important crops -- a development they hope could help the global staple meet the challenges of climate change, disease and population growth.

Wheat is grown across more farmland than any other cereal, and researchers said they're posting its genetic code on the Internet in the hope scientists can use it as a tool to improve harvests. One academic in the field called the discovery "a landmark."

"The wheat genome is the holy grail of plant genomes," said Nick Talbot, a professor of bio-sciences at the University of Exeter, who wasn't involved in the research. "It's going to really revolutionize how we breed it."

In Winnipeg, scientists said the development will trigger a global race to apply the new genetic information. The farmers in countries that employ the genome information first will have a competitive advantage.

That could put pressure on Canada to invest in its premium wheats like Canada Western Red Spring to stay ahead of other countries, the researchers say.

University of Liverpool scientist Neil Hall, whose team cracked the code, said the information could eventually help breeders of varieties of wheat better identify genetic variations responsible for disease resistance, drought tolerance and yield. Although the genetic sequence remains a rough draft and additional strains of wheat need to be analyzed for the work to be useful, Hall predicted it wouldn't take long for his work to make an impact in the field.

"Hopefully the benefit of this work will come through in the next five years," he said.

Strands of genetic information -- DNA -- are the building blocks of life, and an organism's genetic sequence is like an instruction book spelling out which block goes where. Decoding the entire sequence, known as the genome, gives unparalleled insight into how an organism is formed, develops, and dies.

What makes this accomplishment so extraordinary is the complexity of wheat. Its genome is five times the length of the one carried by humans, comprising 17 billion pieces of genetic information.

Wheat is a relative latecomer to the world of genetic sequencing. This year marks the 10th anniversary of the date the human genome was laid bare. Many crops with much smaller genomes have had their DNA sequenced for some time -- rice in 2005, corn in 2009, and soybeans earlier this year.

Wheat is so complicated partly because it is the hybridization of three ancestral species of wild grass.

"That's been one of the challenges. The genome is so huge," said Anita Brule-Babel, plant geneticist at the University of Manitoba. "There's a lot of repetition. There seems to be a lot of wheat DNA that doesn't have a purpose, not that we understand anyway."

But sequencing techniques have improved dramatically over the past decade. The process used in this case is called pyrosequencing, which Hall said allowed his team to monitor a million strands of DNA at a time. He said the sequence took about a year to compile.

Although the code may yet see use by genetic engineers hoping to craft artificial strains of wheat, Hall was at pains to stress the conventional applications of his work. Until now, breeders seeking to combine the best traits of two strains of wheat would cross the pair, grow the hybrid crop and hope for the best.

Although farmers have used that process since wheat was first cultivated 10,000 years ago, Talbot described it as laborious and inefficient.

"Very often we were talking about 10 to 15 years of intensive breeding programs," he said. "We're talking now about doing things in less than five."

But a lot of work needs to be done before that can happen.

"It's very raw data right now. It's like buying this complicated thing from Ikea and dumping it on the floor and realizing you don't have instructions or that little tool they give you to put it together," said Mark Jordan, research scientist in cereal genetics with Agriculture Canada.

For example, wheat has 42 chromosomes (compared to 23 in humans), but researchers don't know yet which DNA belongs to which chromosome, Jordan said.

The first task will be trying to recognize what the genes do, like which genes promote higher yields. The same way researchers look for molecular markers in humans that make some people susceptible to a certain disease, researchers will be looking for markers associated with better yields, Jordan said.

In Brule-Babel's case, she'll be looking for a gene that increases starch content. She is breeding for high starch content to develop a biofuel type of wheat at the U of M.

Some of that information could come from more advanced research in other crops like rice and soybeans. Genes recognized to generate traits in other crops can be recognized and applied in wheat now that the genome is known.

Talbot noted rice cultivation had already benefited from the publication of its genetic code -- and led to the development of vitamin-enriched and drought-resistant strains.

Another positive to come out of the British discovery is scientists will release their information online for the use of scientists around the world. Wheat is one of the last major crops whose research is still in the public domain, said Brule-Babel.

"Most Canadian wheat breeding is publicly funded. It allows us to share information. With other crops, there's no more sharing because it's proprietary information. Or there's no sharing without lawyers writing contracts, and that can take years," she said.

The cracking of wheat's code comes at a time when prices have shot up in the wake of crop failures in Russia, highlighting how the vagaries of world food production can hit import-dependent countries such as Egypt.

Concerns over climate change, water shortages and population growth have loomed in the background for years. New risks include a mutant form of stem rust. The reddish, wind-borne fungus -- known to scientists as Ug99 -- has devastated wheat crops in places such as Kenya, where up to 80 per cent of the wheat in afflicted farmers' fields has been ruined.

Alexander Evans, an expert in resource-scarcity issues at New York University, welcomed the announcement as something that would be "very helpful" in getting farmers to grow "food that will meet those challenges."

bill.redekop@freepress.mb.ca

-- With files from The Associated Press

Republished from the Winnipeg Free Press print edition August 28, 2010 B4