LONDON (Reuters) - Scientists have pinpointed two genes that protect wheat against devastating fungal diseases found worldwide, potentially paving the way to hardier wheat strains, international researchers reported on Thursday.

An Afghan farmer sifts dust out of harvested wheat in Bamiyan, about 240km (149 miles) northwest of Kabul August 26, 2005. REUTERS/Ahmad Masood

New research published in the journal Science showed how the genes provide resistance to leaf rust, stripe rust and powdery mildew, diseases responsible for millions of hectares of lost wheat yield each year.

“Improving control of fungal rust diseases in cereals through breeding varieties with durable rust resistance is critical for world food security,” Simon Krattinger of the Institute of Plant Biology in Zurich and colleagues, wrote in one of the studies.

“The most profitable and environmental friendly strategy for farmers to control wheat rust in both the developing and the developed world is to grow genetically resistant wheat varieties.”

The findings might help farmers one day protect crops without spraying them with fungicides, improve traditional plant breeding techniques and possibly help protect other crops susceptible to the diseases like barley, researchers said.

Krattinger and his team isolated a gene called Lr34 using a resistant wheat line, knocking out genes until they found the one that offered protection.

They do not know exactly what the gene does but believe it produces a protein that transports molecules in a cell that help fight off diseases, Krattinger said.

A problem for plant breeders is that other resistance genes only offer short-term protection because diseases mutate and find new ways to attack a plant. But the Lr34 gene is different because it is far more durable, Krattinger said.

“The gene has been active for more than 50 years,” he said in a telephone interview. “Breeders knew certain plants offered resistance but they didn’t know what the gene was or how it worked. We have identified that.”

In the second study, Cristobal Uauy of the John Innes Center in Britain and colleagues identified a gene called Yr36 found in wild wheat but absent in modern pasta and bread varieties. The gene confers resistance to stripe rust.

Bread wheat provides about 20 percent of the calories eaten by people across the world and is Britain’s biggest crop export, the researchers noted.

“We have recovered a gene that has been lost during domestication,” Uauy said in a telephone interview. “We now have a new tool to combat this disease.”

The researchers do not know what the gene does but believe it recognizes a lipid from a disease and somehow triggers a resistance response, he added.

Like the Lr34 gene, Yr36 appears to offer longer protection and it also seems to fight off more than one strain of stripe rust, he added.

“The idea is if you can have these genes you are buying insurance your crops will be fine and you are protecting your yield,” Uauy said.