The genome sequence of Pantoea ananatis

Pantoea ananatis is a pathogen on a wide range of plants and causes opportunistic human infections. It is frequently isolated from diverse environmental sources including the plant environment and from insects. It thus has an extraordinary ability to survive in a multitude of environmental niches, under a variety of conditions and cause cross-kingdom infections. The genome of a pathogenic strain, isolated from diseased Eucalyptus tissue, was sequenced using 454 technology. The genome consists of a single circular chromosome 4.65 Mb in size with a GC content of 53.7%, encoding 4,140 protein coding sequences (CDS). Genome comparisons against closely related phytopathogens revealed the presence of an exopolysaccharide with high homology to stewartan, the major pathogenicity factor in the corn pathogen, Pantoea stewartii subsp. stewartii A Type III secretion system is absent. Three copies of a novel disease-associated Type VI secretion system are present on the genome. Further comparisons against all available genome sequences indicated a large number of CDS with distinct homology to bacteria occupying specific niches, particularly the plant, insect and animal niches frequented by P. ananatis. The genome sequence of P. ananatis thus gives an indication of an organism that is well adapted to survival in a wide range of environments and that is capable of causing disease symptoms in a number of hosts.