Citrus greening is a plant disease which leads to the death of citrus plants. It is spread through a small bug called the Asian citrus psyllid; the disease leaves a devastating impact on trees at times even killing them. Trees under the impact of citrus greening produce bitter, misshapen, inedible fruit. Citrus greening is also called Huanglongbing (HLB) or yellow dragon disease. This disease appeared for the first time in Florida in 1998 and has till now affected crop industry worth $9 billion in Florida alone. It was cited in California in 2008.
The Yellow Dragon disease is so dangerous that it was feared to wipe out the entire industry in the next decade. Many attempts were made by researchers to find a successful cure for this devastating disease, but got very little success. Cutting down infected trees to keep the bacterium from spreading to healthy trees, was the only known successful remedy for citrus greening, until last week when a team scientists from the University of Florida announced a potential solution.
Scientists at University of Florida analyzed the genome -chemical benzbromarone — which is normally used to treat gout in humans sequences of 10 diverse citrus varieties for the first time. Scientists found that the genome was extremely effective in halting the spread of the bacteria in infected tree shoots. Basically this chemical binds to a protein called LdtR in the bacterium. Once the protein is deactivated, it disrupts a key process that the bacterium needs to survive inside the tree, stopping the virus to spread further. They analyzed and compared the genome sequences of sweet and sour oranges, along with several important mandarin and pummelo varieties.
Although the Scientists tested two other chemicals along with benzbromarone : Hexestrol, which is a carcinogenic synthetic estrogen compound; and Phloretin, which presents the absorption of glucose into the small intestine which had some efficacy toward stopping the spread of citrus greening, but neither of them were as effective as the gout medication on the bacteria.
“Citrus has incestuous genes – nothing is pure. Now that we understand the genetic structure of sweet orange, for example, we can imagine reproducing early citrus domestication using modern breeding techniques that could draw from a broader pool of natural variation and resistance.” said a Faculty member at UF Institute of Food and Agricultural Sciences. Researchers are also trying to trace the cultivation history which traces back to more than 5 million years, all the way to two wild citrus species from Southeast Asia., as they believe it can help in finding the cure of the plant disease.