Première observation de la maladie de la galle du collet causée par Agrobacterium tumefaciens sur l'olivier en Tunisie
Abstract
Abstract We observed for the first time crown gall symptoms in an orchard of olive trees (Olea europaea) of the variety \textquoteleftChemlali\textquoteright \textendash the most widely grown cultivar in Tunisia \textendash in the governorate of Kairouan in central Tunisia. Isolations from symptomatic tissues yielded bacteria that were identified as members of the species complex Agrobacterium tumefaciens using molecular techniques. The isolates were then evaluated for their pathogenicity by inoculating the indicator plant Kalankoë daigremontiana. The virulence of three isolates (O7, O9 and O11) was assessed by PCR amplification of part of the vir region of the Ti-plasmid of Agrobacterium and further confirmed for the O7 isolate by inducing the formation of tumours on \textquoteleftChemlali\textquoteright olive seedlings. These results confirm the susceptibility of the olive tree to Agrobacterium tumefaciens, as previously reported by other researchers in Algeria, Jordan, Australia and Argentina.