UCR graduate student discovers, names bacterium linked to psyll...( RIVERSIDE Calif. To make a discover...)

RIVERSIDE, Calif. To make a discovery and get to name it is just about every scientist's dream. For one graduate student at UC Riverside that dream already has come true.

Allison Hansen, a doctoral student in entomology, has discovered and named a new bacterial pathogen that could be responsible for "psyllid yellows," a disease that infects and kills tomato and potato plants. The disease is spread from plant to plant by the psyllid, a sap-sucking insect. This psyllid commonly is called potato psyllid or tomato psyllid, depending on the plant affected.

Hansen, who joined UCR in 2005 and expects to graduate next year, discovered the bacterium serendipitously through her research on the "symbionts" of the tomato psyllid. (A symbiont is an organism that has an intimate relationship with another organism of a different species.)

She named the pathogen "Candidatus Liberibacter psyllaurous." Liberibacter, she explained, is the genus a category of biological classification in which the bacterium is nested; psyllaurous means psyllid yellows in Latin.

"Allison has a special gift of looking at questions from new perspectives and recognizing relationships that others have either overlooked or missed all together," said Timothy Paine, Hansen's advisor and a professor of entomology. "This ability has enabled her to make a couple of key breakthroughs as a graduate student that have stumped other scientists for decades."

In tomato alone, psyllid yellows resulted in yield losses up to 85 percent and 50 percent in commercial tomato crops in western North America during 2001 and 2004, respectively.

"One symptom of an infected tomato or potato plant with this bacterium is yellowing of the foliage," said Hansen, whose co-adv
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