PATHOGENIC PLAGUE: Stem rust fungus (Puccinia graminis, shown here on bearded wheat) has infected wheat crops for decades. Now, a new race threatens to wipe out even the most resistant strains.© NIGEL CATTLIN/SCIENCE SOURCE
Beneath a steely and frigid Minnesota sky, the warm orange glow of a greenhouse beckons me to enter. But getting inside requires special security clearance and the donning of a white Tyvek gown, and visitors must shower upon leaving. Scrambling up a snowdrift outside the glass building affords me a less encumbered peek at what’s inside: row upon row of wheat plants, riddled with a fungal pathogen that has destroyed countless hectares of the crop in Africa and, more recently, the Middle East.
“There it is, Ug99,” says Brian Steffenson, a plant pathologist at the University of Minnesota, as he taps the glass to point out the dark-red fungus flecking the leaves of the young plants. As they grow, their stems will form large pustules ...
