Résumé
Agrobacterium tumefaciens is a well studied phytopathogen given its various applications for deciphering host-pathogen interactions, bacterial communication, and capacity to transfer DNA fragments into host cells via a membrane protein system, the type IV secretion system (T4SS). T4SS mechanism is similar to the one responsible for antibiotic resistance gene transmission, and new knowledge gained could be applied to other organisms using such a mechanism. As well, A. tumefaciens is of economic importance in biotechnology due to its capacity to generate genetically modified plants. Agrobacterium tumefaciens harbours a plasmid known as Ti plasmid encoding T4SS function genes used for transferring genetic information and plant colonization. In this review, the authors describe the molecular basis of infection, from detection of host signals, to the description of different regions of Ti plasmid key to infection, ending with substrate transfer through bacterial wall. [Journal translation]