Erwinia amylovora CFBP1430

The genus Erwinia currently contains both pathogenic and nonpathogenic bacteria. E.amylovora is a pathogen which causes fire blight, a devastating disease of Rosaceae, which poses a major threat to apple, pear and quince. Fire blight can develop very rapidly and results in scorched symptoms which can kill an entire orchard in a year. The bacterium originated in North America and has spread to other continents; from Europe an eastward advance is threatening the native origin of apple germplasm in Central Asia. It is spread by flower-foraging insects, especially honeybees, in what is thought to be a passive association.This highly virulent strain, CFBP1430, was isolated from hawthorn (Crataegus sp.) in 1972 in France. It is over 99.99% identical to an American isolate ATCC 49946 (ERWAE), suggesting there has been minimal evolution since the global dispersion of E.amylovora. There has however been a large-scale rearrangement of the genome resulting in a position exchange of 2 large portions of the chromosome. Additionally ERWAE has a second larger plasmid (pEA72) associated with it. Interestingly 1 type III secretion system has high homology to the insect endosymbiont Sodalis glossidinius str. morsitans (SODGM) perhaps suggesting a closer insect association beyond the known passive dispersal. Comparison with pathogenic E.pyrifoliae and the epiphyte E.tasmaniensis will hopefully shed light on the mechanisms of virulence and host range and provide information to help combat this devastating pathogen (adapted from PMID 20118253 and 20192826). (HAMAP: ERWAC)