Identification of novel pathogenicity-related cellulase genes in Xanthomonas oryzae pv. oryzae

Twelve genes encoding cellulases, including endo- and exoglucanases, were identified from the genomic database of Xanthomonas oryzae pv. oryzae KACC10331. The genes were amplified by polymerase chain reaction (PCR) from X. oryzae pv. oryzae KACC10859 and mutated by transposon insertion; further, marker exchange was performed with the target genes of the wild type strain. Homologous recombination events were confirmed by PCR and Southern hybridization analysis. We found that the mutant strains eglXoA::Tn5, eglXoB::Tn5, and celXoB::Tn5 were completely virulence-deficient. In addition, mutants celbXoA::Tn5, bglXoC::Tn5, and bglXoF::Tn5 showed attenuated virulence, while the virulence of other mutants was not affected.

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► Twelve cellulase genes in X. oryzae pv. oryzae genome were mutated by transposon insertion.
► Pathogenicity and complementation of the mutants were assayed on rice leaves.
► eglXoA, celXoB, celbXoA, bglXoC and bglXoF were identified as novel pathogenicity-related genes.