Doomsday Is Only A Calamity Away.
By Brendan I. Koerner, Wired | March 2010
Riding the winds, Ug99 has breached the best defenses science can offer. Photo: Gallery Stock
As they queue to fill water jugs from a rusty communal tap, the women of Njoro can't help but gawk at the odd scene across the road. In a wheat field ringed by barbed wire, a dozen men wearing white polyethylene jumpsuits stand in a tight huddle, eyes fixed on the green-and-amber stalks that graze their knees. They chat in foreign tongues— Urdu, Farsi, Chinese— that are rarely heard here amid the acacia trees and donkey carts of Kenya's Rift Valley. The men's hazmat-style safety gear suggests they might be hunting down one of the infamous viruses that flourish in this part of the world— Ebola, perhaps, or Marburg.
Then the leader of the huddle, Harbans Bariana, a rotund Australian in an undersize safari hat, begins reading aloud from his clipboard: "Wylah"? he asks. His colleagues bend down to examine some flaccid plants flecked with red splotches. A lanky Pakistani with a salt-and-pepper beard rakes a finger along one of the mottled stalks; an iodine-like residue rubs off on his skin. "40 S," he calls out.
The men move three steps right to a slightly more robust clump of wheat. The Australian asks: "Yandanooka"? "25 MR"? comes the tentative reply from a mustachioed Nepali in a green baseball cap. They slide over to inspect another stalk, and then another. To the women at the tap, faces scrunched in puzzlement, the call-and-response sounds like gibberish— and to most of the world, it is. But to the jumpsuited strangers in East Africa— a group of elite plant pathologists— these codenames and numbers are a lingua franca, describing just how badly a crop has been ravaged by disease.
These specialists have come to Njoro on this autumn afternoon to study a scourge that is destroying acres of Kenyan fields. The enemy is Ug99, a fungus that causes stem rust, a calamitous disease of wheat. Its spores alight on a wheat leaf, then work their way into the flesh of the plant and hijack its metabolism, siphoning off nutrients that would otherwise fatten the grains.
The pathogen makes its presence known to humans through crimson pustules on the plant's stems and leaves. When those pustules burst, millions of spores flare out in search of fresh hosts. The ravaged plant then withers and dies, its grains shriveled into useless pebbles. Stem rust is the polio of agriculture, a plague that was brought under control nearly half a century ago as part of the celebrated Green Revolution. After years of trial and error, scientists managed to breed wheat that contained genes capable of repelling the assaults of Puccinia graminis, the formal name of the fungus.
But now it's clear: The triumph didn't last. While languishing in the Ugandan highlands, a small population of P. graminis evolved the means to overcome mankind's most ingenious genetic defenses. This distinct new race of P. graminis, dubbed Ug99 after its country of origin (Uganda) and year of christening (1999), is storming east, working its way through Africa and the Middle East and threatening India and China. More than a billion lives are at stake. "It's an absolute game-changer," says Brian Steffenson, a cereal-disease expert at the University of Minnesota who travels to Njoro regularly to observe the enemy in the wild. "The pathogen takes out pretty much everything we have."
Indeed, 90 percent of the world's wheat has little or no protection against the Ug99 race of P. graminis. If nothing is done to slow the pathogen, famine could soon become the norm— from the Red Sea to the Mongolian steppe— as Ug99 annihilates a crop that provides a third of our calories. China and India, the world's biggest wheat consumers, will once again face the threat of mass starvation, especially among their rural poor. The situation will be particularly grim in Pakistan and Afghanistan, two nations that rely heavily on wheat for sustenance and are in no position to bear added woe. Their fragile governments may not be able to survive the onslaught of Ug99 and its attendant turmoil.
The pathogen has already been detected in Iran and may now be headed for South Asia's most important breadbasket, the Punjab, which nourishes hundreds of millions of Indians and Pakistanis. What's more, Ug99 could easily make the transoceanic leap to the United States. All it would take is for a single spore, barely bigger than a red blood cell, to latch onto the shirt of an oblivious traveler.
The toll from that would be ruinous. The US Department of Agriculture estimates that more than 40 million acres of wheat would be at serious risk if Ug99 came to these shores, where the grain is the third most valuable crop, trailing only corn and soybeans. The economic loss might easily exceed $10 billion. A simple loaf of bread could become a luxury.
"If this stuff gets into the Western Hemisphere," Steffenson says, "God help us all." He and his fellow scientists around the world are scrambling to halt the pathogen. To do so, they must figure out a way to reach deep within the wheat genome and create genetic barriers that Ug99 cannot overcome. And they must do so quickly, before the pestilence moves on to the next continent, and then the one after that— wreaking havoc on the world's food supply.
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Important cereals: A. Oats (Avena sativa); B. Barley (Hordeum vulgare); C. Bread Wheat (Triticum aestivum); D. Rye (Secale cereale). Wheat and rye are crossed together to produce the hybrid triticale.
Rice (Oryza sativa) is one of the most important crop plants, and feeds more people than any other single plant species on earth. According to Simson and Ogarzaly (Economic Botany: Plants in Our World, 1995), it has been estimated that 1.7 billion people depend on rice. ]
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