Citrus variegated chlorosis (Xylella fastidiosa) can be transmitted through natural root grafts
Citrus variegated chlorosis is caused by Xylella fastidiosa (EPPO A1 quarantine pest). The bacterium can be spread over long distances by infected nursery trees and is transmitted in orchards by insect vectors. Studies have been carried out in Brazil on the distribution of X. fastidiosa within citrus roots and it was shown that the bacterium can colonize root systems. In addition, pot experiments with Citrus sinensis plants (1 inoculated and 1 non-inoculated plant per pot) showed that X. fastidiosa could be transmitted between citrus plants through natural root grafts. This is the first time that this mode of transmission is reported. Further studies are needed to evaluate the actual importance of transmission through natural root grafts in the epidemiology of the diseases caused by X. fastidiosa on its various host plants.
He, C.X.; Li, W.B.; Ayres, A.J.; Hartung, J.S.; Miranda, V.S.; Teixeira, D.C. (2000) Distribution of Xylella fastidiosa in citrus rootstocks and transmission of citrus variegated chlorosis between sweet orange plants through natural root grafts.
Plant Disease, 84(6), 622-626.