A while back, Jason blogged briefly on a New Scientists article about the rise of a new Puccinia graminis strain, Ug99, that is spreading through West African wheat fields at an enormous rates. It looks like this story is growing in the scientific conciousness, as Science is now running an article on the spread of this wheat pandemic.
The article has a nice bit of background regarding the rise of the disease. It seems that it is spreading so quickly for due to its relatively broad host range compared to other strains. While scientists have been working to derive resistant wheat varieties, Puccinia has successfully foiled their recent attempts by mutating to acheive resistance to the plant expressed Sr24.
To boot, this strain has been found in Yemen, allowing its spores to hitch a ride along the winds that blow north along the Indian Ocean, putting much of the global bread basket at risk (I imagine that the last thing the middle east needs right now is a wheat shortage). The last time a rust spread through this area, it caused 1 billion dollars in damage. Given the extensive host range of this variety, experts predict that damages will exceede at least three times this amount.
Fortunately, researchers in Ethiopian have derived two wheat strains that may be resistant to Ug99. However, it can take several years to get these wheat strains in the ground and, ultimately, no one is certain that Ug99 won’t cleverly find a way to adapt resistance. We should keep our ears to the rail on this one: it could be a big problem.