Stationary-phase variation due to transposition of novel insertion elements in Xanthomonas oryzae pv. oryzae.
Xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. Spontaneous mutants which are deficient for virulence and extracellular polysaccharide (Eps) production accumulate in large numbers in stationary-phase cultures of this bacterium, a phenomenon which we have called stationary-phase variation. A clone (pSD1) carrying the Eps biosynthetic gene (gum) cluster of X. oryzae pv. oryzae restored Eps production and virulence to several spv (for stationary-phase variation) mutants. Data from localized recombination analysis, Southern hybridization, PCR amplification, and sequence analysis showed that the mutations are due to insertion of either one of two novel endogenous insertion sequence (IS) elements, namely, ISXo1 and ISXo2, into gumM, the last gene of the gum gene cluster. The results of Southern analysis indicate the presence of multiple copies of both IS elements in the genome of X. oryzae pv. oryzae. These results demonstrate the role of IS elements in stationary-phase variation in X. oryzae pv. oryzae.
Centre for Cellular and Molecular Biology, Hyderabad 500 007, India.
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D000483:Alleles; D001483:Base Sequence; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D015321:Gene Rearrangement; D005798:Genes, Bacterial; D018740:Genetic Heterogeneity; D014644:Genetic Variation; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D012275:Oryza / Q000382:microbiology; D010641:Phenotype; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D011135:Polysaccharides, Bacterial / Q000235:genetics*; D014974:Xanthomonas / Q000235:genetics* / Q000254:growth & development / Q000502:physiology
D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D011135:Polysaccharides, Bacterial; C002563:xanthan gum