New research may help protect citrus from an exotic disease called huanglongbing or citrus greening.

Citrus' Huanglongbing Disease Voted Top Research Proposal

By Marcia Wood
November 9, 2006

Huanglongbing, an exotic citrus disease that’s also known as citrus greening, is the focus of the top-ranked research proposal in the Agricultural Research Service's (ARS) 2007 Postdoctoral Research Award Program.

California-based ARS plant physiologist Hong Lin wrote the proposal, which received the highest score in the agency’s annual in-house competition. He will receive the agency's T.W. Edminster Award and $120,000 to fund a two-year postdoctoral position in his laboratory at the ARS San Joaquin Valley Agricultural Sciences Center near Parlier, Calif. Lin also will be honored at the ARS annual awards ceremony in 2007.

The postdoc that Lin hires will work with him to develop a fast, reliable test to detect the microbe that causes Huanglongbing, or HLB, in oranges, lemons and other familiar citrus. Early and reliable detection of the microbe—a bacterium known to scientists as Candidatus Liberibacter—is essential to stopping its spread, according to Lin. The new diagnostic test will be based on analysis of samples of the culprit microbe's genetic material, or DNA.

The bacterium was detected in the United States for the first time in 2005, in Florida. It can weaken or kill citrus trees or cause them to stop bearing fruit. Tiny, winged insects known as psyllids spread the microbe. Huanglongbing also occurs in the tropics and subtropics of Asia, India, Africa and South America.

Also under the ARS 2007 Postdoctoral Research Award Program, another 49 ARS scientists from around the country will receive $100,000 to fund two-year postdoc positions. Their investigations will cover such subjects as determining the effectiveness of fruit and vegetable compounds in preventing cancer and other diseases, improving corn plants' ability to withstand drought, finding genetic markers that predict pork quality, and exploring a high-tech approach to detecting pathogens on food.

ARS is the U.S. Department of Agriculture's chief scientific research agency.