Genome Sequence of Xanthomonas oryzae pv. oryzae Suggests Contribution of Large Numbers of Effector Genes and Insertion Sequences to Its Race Diversity

Abstract

The plant-pathogenic prokaryote Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight, one of the most important diseases of rice. The bacterium is a model organism for the analysis of plant-pathogen interaction, because more than 30 races differing in virulence and 25 resistance genes in rice have been reported to date. We present here the complete genome sequence of Xoo strain MAFF 311018. The size of the genome was 4,940,217 bp, in a single circular chromosome. The genome structure of Xoo MAFF 311018 was characterized by large numbers of effector (avr) genes of the avrBs3/pth family and insertion sequences (ISs). RFLP analysis of diverse strains using ISXo1 as a probe suggests that the prevalence of mobile elements in this species, which can bring about genome inversions and rearrangement, may have played a major role in generating the high degree of genetic diversity and race differentiation characteristic of this pathogen. The Xoo MAFF 311018 sequence was also highly similar to those of X. axonopodis pv. citri and X. campestris pv. campestris with the exception of the large number of effectors and IS elements, and numerous inversions and rearrangements.

Activation of the Indole-3-Acetic Acid–Amido Synthetase GH3-8 Suppresses Expansin Expression and Promotes Salicylate- and Jasmonate-Independent Basal Immunity in Rice

“…In addition, R gene-mediated Xoo resistance accompanies the suppression of auxin signaling. A search of the amino acid sequences of Pseudomonas syringae pv syringae iaaH and iaaM (Mazzola and White, 1994) against the putative encoding products of the Xoo (strains KACC10331 and MAFF311018) whole genome sequence (Lee et al, 2005;Ochiai et al, 2005) did not reveal any homologous sequence. We then searched databases and found that Xoo carries NIT proteins (National Center for Biotechnology Information protein database accession numbers AAW74756, AAW74754, and YP_200139), which may contribute to the accumulation of IAA.…”

Host and Pathogen Factors Controlling the Rice-Xanthomonas oryzae Interaction

“…The genomic sequences are available for three strains of Xoo and one strain of Xoc (Lee et al, 2005;Ochiai et al, 2005;Lu et al, 2008;Salzberg et al, 2008). The full complement of TAL T3 effectors are now known for two strains of Xoo and one strain of Xoc, and both pathogens are unusual due to the high number of TAL effector genes within their individual genomes.…”

“…At the same time, two lines of evidence indicate that strains of Xoo could defeat Xa27. First, avrXa27 is present in a single copy, at least in the two strains that have been examined; therefore, simple loss or mutation of the gene converts incompatible strains to compatible strains on plants with Xa27 (Gu et al, 2005;Ochiai et al, 2005). Second, mutation of avrXa27 in the strain PXO99 A converts PXO99…”

“…A and MAFF311018 (also named T7174) have 19 and 17 genes, respectively, organized in nine and eight regions of their respective genomes (Ochiai et al, 2005;Salzberg et al, 2008;Fig. 5).…”

Development of a Database of Plant Diseases in Japan and a System for Making Microorganism Genetic Resources and their DNA Sequence Data Available to the Research Community

“…The genetic resources available for distribution to researchers include strains of Xanthomonas oryzae pv. oryzae 4 and Mesorhizobium loti 3 , the entire genome sequences of which have been determined.…”