The genomic sequences of the fire blight antagonists Erwinia tasmaniensis and Erwinia billingiae compared with virulence regions of other Erwinia species

The genomes of Erwinia tasmaniensis Et1/99 and E. billingiae Eb661 have been sequenced with a chromosome size of 3.8 and 5.1 Mb, respectively. They are antagonistic against Erwinia amylovora causing fire blight on rosaceous plants such as apple and pear. Major differences are the ability of E. tasmaniensis to induce HR on non-host plants, but lacks EPS synthesis and the ability to metabolize sorbitol. E. billingiae produces EPS, metabolizes sorbitol, but lacks HR and sucrose metabolism. E. tasmaniensis Et1/99 carries five plasmids from 9 to 45 kb, and Eb661 two large plasmids, which exceed 100 kb. All analyzed Erwinia species carry an EPS-encoding region with high homology to the ams-cluster of E. amylovora. The hrp/dsp region of E. tasmaniensis is highly related to the corresponding regions of E. amylovora and E. pyrifoliae, but absent in the draft genome sequence of E. billingiae.