University of Florida researchers say they have developed genetically modified citrus trees that resist the greening disease that threatens to destroy the industry. Citrus greening, spread by the tiny psyllid lice, causes misshapen fruit and eventually kills most infected trees. The disease was first confirmed in Florida in 2005.
Professor Jude Grosser and research assistant scientist Manjul Dutt isolated a gene from the Arabidopsis plant, a member of the mustard family, to create the new trees, says a U-Florida release. The work resulted in trees that “exhibited enhanced resistance to greening, reduced disease severity and even several trees that remained disease-free after 36 months of planting in a field with a high number of diseased trees.”
Grosser and Dutt worked with two lines of sweet orange cultivars to create trees that produce anti-pathogen proteins. “The next steps include transferring this gene into additional commercial varieties and rootstocks that are commonly grown in Florida. In addition, researchers must ‘stack’ this gene with another transgene that provides resistance to the greening bacterium by a completely different mechanism,” says U-Florida. “That will prevent the pathogen from overcoming the resistance in the field. It will still be several years before such trees will be available for commercial use.”