( Researchers have found a gene they susp...)Researchers find gene that may be at root of potato blight

And the pathogen that contains this gene still causes massive amounts of agricultural damage throughout the modern world?on the order of billions of dollars each year.

The scientists describe the gene, called Avr3a, in a study that appears online in the early edition of the Proceedings of the National Academy of Sciences.

Researchers call Avr3a an avirulence gene. This gene is the first avirulence gene identified from the plant pathogen that causes late blight, a devastating disease that can destroy fields of potato and tomato plants. Plant pathogens contain a diverse set of such avirulence genes which, depending on the plant variety, can either facilitate disease or trigger resistance.

Avr3a scouts a potato plant on the cellular level to determine whether the plant is a likely victim.

"This avirulence gene is kind of like a weapon that triggers a metal detector," said Sophien Kamoun, a study co-author and an associate professor of plant pathology at Ohio State University 's Ohio Agricultural Research and Development Center in Wooster .

"If you take a gun through the metal detector at an airport, the alarms go off," he said. "This gene (Avr3a) sends a signal alerting the plant that it is infected by the pathogen."

Phytophthora infestans is the pathogen that causes late blight. For decades, controlling this disease has involved regular applications of agrochemicals, Kamoun said.

But some experts fear that the pathogen is making a comeback.

"Given the recent widespread occurrence of new fungicide-resistant strains of this pathogen, it could be considered a reemerging threat to global food security," Kamoun said. "Disturbing reports predict that potato late blight could cause food shortages and hunger in several parts of the world."

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Source:Ohio State University