Endophytic bacterial community in yellows infected and recovered grapevine plants

Flavescence dorée (FD) and Bois Noir (BN) are grapevine yellows (GY) diseases that cause severe crop losses. FD is caused by “Candidatus Phytoplasma vitis”, transmitted by the leafhopper Scaphoideus titanus and BN is caused by “Candidatus Phytoplasma solani” and transmitted by Hyalesthes obsoletus. Up to now, FD control is based on chemical treatments against the insect vector and eradication of diseased plants. Recently, great importance has been placed on recovery, the spontaneous remission of symptoms in GY-diseased grapevines. Its causes are still little known although cytochemical and biochemical studies suggest that systemic acquired resistance (SAR) might be involved. Also, it is known that some species of bacteria are able to protect plants against pathogens. This work has aimed to identify the endophytic bacterial community present in Vitis vinifera L. and to examine the possible correlation between recovery and endophytic microrganisms. Endophytic bacteria were identified and characterized by screening the 16S rDNA library. The sequence data showed the presence of bacterial species belonging to the Gamma-proteobacteria, family Enterobacteriaceae. Among them, Pantoea agglomerans, Pantoea ananatis, Ewingella americana and Erwinia persicina were frequently identified. In the same samples,Bacillus, Enterococcus and Curtobacterium were obtained using cultivation-based methods. Further studies done to examine their possible involvement in phytoplasma recovery in grapevine.