Azospirillum lipoferum 4B was isolated from a rice field in Camargue (in the south of France) in 1982 and has been studied for its high efficiency in nitrogen fixation and for its successful properties of rice colonization and growth promotion. It exhibits mixed flagellation, i.e. it grows with a single polar flagellum in liquid medium and additional lateral flagella on a solid medium. Comparison of 2 fully sequenced Azospirillum (strain 4B plus strain B510, AZOS1) and an incomplete genome A.brasilense Sp245, suggest that horizontal gene transfer has affected nearly 50% of the Azospirillum genomes, in close association with dramatic changes in lifestyle necessary for transition from aquatic to terrestrial environments and association with plants (adapted from www.genoscope.cns.fr/spip/Azospirillum-lipoferum-a-bacterial.html?var_recherche=Azospirillum, PMIDs 10508112 and 22216014).