show Abstracthide AbstractGenomic Analysis of Xanthomonas oryzae from US Rice Reveals Substantial Divergence from Known X. oryzae Pathovars L.R. Triplett, J.P. Hamilton, C.R. Buell, N.A. Tisserat, V. Verdier, F. Zink, and J.E. Leach The species Xanthomonas oryzae is comprised of two designated pathovars, both of which cause economically significant diseases of rice in Asia and Africa. Although X. oryzae is not considered endemic to the United States, an X. oryzae-like bacterium was isolated from US rice and southern cutgrass in the late 1980s. The US strains were weakly pathogenic and genetically distinct from characterized X. oryzae pathovars. In the current study, draft genome sequence from two US Xanthomonas strains revealed that the US strains form a novel clade within the X. oryzae species, distinct from all strains known to cause significant yield loss. Comparative genome analysis revealed several putative gene clusters specific to the US strains, and supported previous reports that the US strains lack Transcriptional Activator Like (TAL) effectors. In addition to phylogenetic and comparative analyses, the genome sequence was used for designing robust US strain-specific primers, demonstrating the usefulness of draft genome sequence in the rapid development of diagnostic tools. Appl. Environ. Microbiol. 2011 0: AEM.00028-11