Department Details Ohio Pavement Striping Transportation


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Department Details Ohio Pavement Striping Transportation

Department Details Ohio Pavement Striping Transportation

Four newly identified strains of the deadly grain fungus, Puccinia graminis were reported this June at a meeting of the Borlaug Global Rust Initiative (BGRI) hosted by Cornell University and held in St. Petersburg, Russia. The experts concluded that the evolving pathogens may be an even greater threat to global wheat production than the original TTKSK pathotype, more commonly known as Ug99, which was discovered in southwestern Uganda in 1998.

Wheat at Risk from Both Invading and Mutating Fungi

Two of the new stem rust variants have been DNA fingerprinted by Botma Visser and colleagues at the University of the Free State in Bloemfontein, South Africa and the University of Sydney in Camden, Australia. The TTKSP strain has a fingerprint identical to TTKSF which is common in South Africa, whereas PTKST is similar to TTKSP but differs in the lines of wheat it can infect.

This difference suggests that TTKSP is a local mutation whereas the PTKST strain was exotically introduced into South Africa, “and highlights the vulnerability of the wheat industry to foreign invasions of these pathogens,” says Visser who stresses that “P. graminis is highly adapted to long-distance migration through wind dispersal and rain deposition of its urediniospores,” adding that accidental transport of spores on contaminated clothing or goods contributes to fungal spread.

Ninety Percent of the World's Wheat in Danger

There are now seven known Ug99 mutations able to defeat stem rust (Sr) resistance genes and 90 percent of the world’s wheat has little or no protection against them. This is important, say Ravi P. Singh and Arun Kumar Joshi from the International Maize and Wheat Improvement Center in El Batan, Mexico and Kathmandu, Nepal respectively, because wheat alone provides nearly 55 percent of the carbohydrates and 20 percent of the food calories consumed globally. According to BGRI, wheat represents approximately 30 percent of the global grain crop each year and at last count, which was in 2007, 607 million tons were produced; nearly half of which harvested in developing countries.

Notably, since its discovery, Ug99 or its variants have spread to Kenya, Ethiopia, Sudan, Yemen and Iran. Rust fungi within the Ug99 lineage have also been spotted in South Africa and Zimbabwe. Scientists are concerned that one or more of these strains will enter Punjab, one of the world's great bread baskets.

Scientists Armed and Ready to Attack Evolving Mutants

“Because of its destructiveness and the economic importance of its cereal hosts - which include barley, oats and rye in addition to wheat - P. graminis is one of the most widely studied of all plant pathogens,” according to Les J. Szabo from the US Department of Agriculture’s Cereal Disease Laboratory at the University of Minnesota in St. Paul.

The St Paul facility is one of the two research centers in the world legally permitted to work with exotic cereal rust pathogens and where experiments with live culture are allowed (only during December through February each year). The other lab is in Winnipeg, Manitoba; both are purposely located in frigid climates so if fungal spores escape it is unlikely they would survive the icy, barren neighboring fields.