Research Programs |
Citrus Canker Resistance
The production of citrus has become imperiled by the unabated spread of the bacterial disease citrus canker. The United States is the third largest citrus producer in the world, with the greatest citrus production occurring in Florida, valued at more than $9 billion. Severe economic consequences from citrus canker have occurred from the loss of marketability of fruit, reduction in fruit production and tree vigor, extra control measures, and the substantial cost incurred by eradication efforts. Unsuccessful attempts to eliminate the disease between 1996 and 2006 by eradication resulted in a cost of $1.2 billion and the destruction of 7 million commercial and 5 million nursery and residential trees, the largest plant-pest eradication effort ever carried out in the U.S.
Citrus canker is characterized by specific symptoms, most notably raised lesions, and is caused by the bacterial pathogen Xanthomonas citri subsp. citri (Xc). Like other bacterial pathogens, all citrus canker strains produce proteins known as effectors that are injected into their plant hosts to help in the establishment of infection.
2Blades is developing effective citrus canker resistance based on a specific class of effectors known as Transcription Activator Like (TAL) effectors. Bacteria use these proteins to ramp up the expression of host genes that will improve conditions for establishing disease, however, some plants have evolved the means of activating resistance genes by the same mechanism. Our project uses this mechanism to engineer new disease resistance genes that are induced by the specific TAL effectors present in all Xc strains.
