First and seventh authors: Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto Prefectural University, Kyoto 606-8522, Japan; second, third, and sixth authors: National Institute of Agrobiological Sciences, Tsukuba 305-8602, Japan; fourth author: Laboratory of Molecular Plant Pathology, School of Bioresources, Hiroshima Prefectural University, Shobara 727-0023 Japan; and fifth author: Faculty of Agriculture, Miyazaki University, Miyazaki 889-2155, Japan
Go to article:
Accepted for publication 11 January 2004.
Xanthomonas oryzae pv. oryzae, the causal agent of bacterial leaf blight of rice, was subjected to transposon mutagenesis to generate mutants defective in pathogenicity. A novel mutant 74M913 was attenuated in virulence but retained its ability to cause the hypersensitive response in leaf blight-resistant rice and tomato. Cloning and sequence analysis revealed that the transposon in 74M913 was inserted in a gene homologous to the phosphoglucose isomerase (pgi) gene of X. axonopodis pv. citri. Growth of the mutant in a synthetic medium containing fructose or xylose as a sole carbohydrate source was much reduced, indicating the transposon disrupted pgi function. The interaction between expression of pgi and hypersensitive response and pathogenicity (hrp) genes was investigated because we had demonstrated previously that expression of hrp genes of X. oryzae pv. oryzae is induced in a synthetic medium containing xylose. However, pgi and the hrp gene (hrcU) were expressed independently. This study suggests that PGI is involved in pathogenicity of X. oryzae pv. oryzae.
© 2004 The American Phytopathological Society