Genome-wide identification of pathogenicity genes in Xanthomonas oryzae pv.oryzae by transposon mutagenesis

摘要

A transposon mutant library was constructed from the bacterial blight pathogen Xanthomonas oryzae pv.oryzae(Xoo)KACC10331 by Tn5 transposon mutagenesis.The susceptible rice cultivar Milyang 23 was inoculated with a total of 24 540 mutants resistant to kanamycin and 67 avirulent or reduced-pathogenicity mutant strains were selected for study.Southern hybridization verified that 84 mutant strains had single-copy insertions and their single-transposon insertion sites were identified by sequencing analysis combined with thermal asymmetric interlaced(TAIL)-PCR.The single-transposon-tagged sequences of 21 mutant strains belonged to pathogenicity-related genes previously reported in Xanthomonas species,while the other 46 single-transposon-tagged sequences included diverse functional genes encoding,five cell-wall-degrading enzymes,three fimbrial and flagella assembly regulators,five regulatory proteins,15 metabolic regulators and 18 hypothetical proteins,which were identified as novel pathogenicity genes of Xoo.