By Barbara Liston
ORLANDO, Fla., June 4 (Reuters) - A chemical used to treat gout in humans has been found to halt the spread of the fatal citrus greening disease that is devastating Florida's $9 billion citrus industry, according to scientists.
"We're really hopeful," University of Florida microbiologist Graciela Lorca told Reuters on Wednesday, saying the chemical impeded the spread of the disease in 80 per cent of citrus tree specimens during an experiment at the school.
As much as 70 per cent of Florida's citrus trees are believed to be infected by greening, which is caused by bacteria deposited on trees by an insect called the Asian Citrus Psyllid.
The best method now for dealing with greening calls for removing infected trees to prevent the bacteria from spreading to others in a grove.
Even if Lorca's work turns out to be the long-sought silver bullet to stop the advance of the disease, it could take five to seven years under government testing requirements for the treatment to receive federal approval for commercial use.
The research led by Lorca and her husband, University of Florida microbiologist Claudio Gonzalez, was published in late April by the online peer-reviewed journal PLOS Pathogens.
Greening is a fast-spreading disease that has cost Florida's economy an estimated $4.5 billion in lost revenues since 2006, according to the University of Florida's Institute of Food and Agriculture Sciences. Greening was also detected in 2012 in California.
University of Florida horticulturists are also testing new citrus rootstocks that appear to withstand greening. The rootstocks' resistance was discovered by chance while the scientists were testing the ability of new fruit tree cultivars to thrive in poor soil, cold temperatures and other stresses.
Lorca said the research team spent three years testing 1,200 compounds against a protein in the disease that they determined regulated genes that helped the bacteria survive in the plant.
Three compounds - phloretin, hexestrol and, particularly, benzbromarone, which is used for gout - worked best, Lorca said.
"We are actually looking at how the bacteria is dying in the plant," Lorca said.
The team next needs government approval to conduct field testing, she said.
Florida growers are eager for an answer to greening.
"Every grower I know is just hanging by their fingernails, hoping and praying for a new discovery for treatment," said Ellis Hunt Jr. of Lake Wales, quoted in a University of Florida press release and whose family has been in the citrus business since 1922. (Editing by David Adams and Peter Cooney)
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