The devastating disease Huonglongbing, or citrus greening, looms darkly over the United States, threatening to wipe out the nation's citrus industry, whose fresh fruit alone was valued at more than $3.4 billion in 2012.
Recently, however, a research team led by a University of California, Davis, plant scientist used DNA sequencing technologies to paint a broad picture of how citrus greening impacts trees before they even show signs of infection, offering hope for developing diagnostic tests and treatments for the currently incurable disease.
"Florida is seemingly in the death grip of citrus greening, and many experts believe it is just a matter of time before the disease appears full force in California," said plant molecular biologist Abhaya Dandekar, lead author on the study.
The new findings indicate that the bacterial disease interferes with starch and sugar metabolism in young and matures leaves and fruit, while also wreaking havoc with hormonal networks that are key to the trees' ability to fend of infections. Study results will be reported Sept. 25 in the journal PLOS ONE.
"Because the disease has a long latent phase during which there are no symptoms of infection and the bacteria are resistant to being grown in the laboratory, the only option for halting transmission of citrus greening has been to apply chemical pesticides to control the insect that spreads the bacteria," Dandekar said.
About citrus greening:
HLB, or citrus greening, is the most destructive citrus disease worldwide. It is caused by three species of the Candidatus Liberibacter bacteria, including Candidatus Liberibacter asiaticus, which is known by the acronym CaLas. These bacteria are carried from tree to tree by two species of the citrus psyllid, a winged insect that is about one-eighth inch long and attaches itself to the underside of the trees' leaves.
As the citrus psyllid feeds on a leaf, it c
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University of California - Davis