Erwinia tasmaniensis Et1/99

The genus Erwinia currently contains both pathogenic and nonpathogenic bacteria. E.tasmaniensis are nonpathogenic Erwinia isolated from fruit trees; strain Et1/99, the type strain, was isolated from apple flowers in Tasmania, Australia. It consists of a 3.9 Mb circular chromosome and five plasmids. Strain Et1/99 represents an epiphytic plant bacterium related to E.amylovora and E.pyrifoliae, which are responsible for the important plant diseases fire blight and Asian pear shoot blight, respectively. Strain Et1/99 is thought to compete with these and other bacteria when occupying the same habitat during initial colonization and may represent a strategy for controlling the early steps of fire blight. Secretion systems include the hypersensitive response type III pathway present in many pathogens. Differences or missing parts within the virulence-related factors distinguish strain Et1/99 from pathogens such as Pectobacterium atrosepticum and the related Erwinia spp. Strain Et1/99 completely lacks the sorbitol operon, which may also affect its inability to invade fire blight host plants. Erwinia amylovora in contrast depends for virulence on utilization of sorbitol, the dominant carbohydrate in rosaceous plants (modified from PubMed 18462403). (EBI Integr8)