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Newly Explored Rice Gene Could Help "Blast" Killer Fungus
By Erin Peabody
August 12, 2004
Rice plants could soon be getting their own version of "caller ID." Agricultural Research Service scientists are providing plants of this important world crop with the genetic tools needed to recognize and identify incoming attacks from the damaging pathogen known as rice blast. The fungus, Magnaporthe grisea, causes rice yield losses of up 30 percent each year worldwide.
Two-thirds of the global population relies on rice. And while many farmers around the world are growing record amounts of the staple grain--thanks to new rice varieties and advances in nutrient and pest management--they can't compete with the blast fungus' will to survive.
According to ARS chemist Sally Leong, blast is so adaptable that it can defeat a rice cultivar, specially bred to resist the fungus, after just one growing season. Leong works at the agency's Cereal Crops Research Unit in Madison, Wis.
Trying to escape the tug-of-war scenario that rice breeders find themselves in when searching for new, blast-resistant plants every one to three years, Leong is working to arm important rice varieties with more certain, long-lasting genetic advantages.
She's been studying two key genes--one from a resistant rice cultivar and one from the M. grisea pathogen--to understand precisely how hardy rice plants defend themselves when confronted with infectious spores of the blast fungus. Early recognition of the fungal perpetrator is key to successful plant protection.
Having evolved alongside each other in many parts of the world, rice and its blast pathogen possess genes with a unique history. As such, a rice plant will launch a strong defense response against M. grisea if its resistance gene matches a related, counter-resistance gene in the fungus.
Leong is developing rice plants with the resistance gene. She and colleagues are also researching how to optimally apply the M. griseaa gene to already-resistant rice plants to achieve even greater blast-readiness in rice.
Read more about the research in the August issue of Agricultural Research magazine, available online at:
ARS is the U.S. Department of Agriculture's chief scientific research agency.
