Resistance to canker disease in transgenic pineapple sweet orange plants by dermaseptin expression.

FURMAN N., KOBAYASHI K., GARCIA M.L., MENTABERRY A

Congreso; SAIB; 2011

Orange production has significant contribution to regional economies of Argentina. Citrus canker disease, caused by the bacterium Xanthomonas axonopodis pv. citri (Xac) is the most important diseases of citrus causing important economic losses worldwide. No natural resistance was found in commericial orange cultivars or feedstock plants. Disease control is limited to agronomical practices and/or eradication of infected individuals. We developed a biotechnological strategy based on the expression of the dermaseptine antimicrobial peptide in transgenic Pineapple sweet orange plants. Pineapple sweet orange and N. benthamiana plants were transformed by Agrobacterium tumefaciens method to express constitutively the dermaseptine and the signal peptide sequence targeting to the apoplastic space. Bacterial growth inhibition assays were performed in vitro using extracts from transgenic N. benthamiana plants, observing a clear inhibition of Xac growth. In planta assays performed using two selected transgenic Pineapple sweet orange lines, Xac suspended solution was sprayed on the surface of punctured leaves (6 punctures per leaf) and the canker developments were followed up to 50 days and evaluated under dissecting microscope. Analysis of 70 to 100 punctures per/plant showed consistently a lower frequency of the of severe canker symptoms in transgenic citrus lines compared to control plant.