1. Self-regulation of a new pathogenicity-related gene encoding leucine-rich protein LrpX in Xanthomonas oryzae pv. oryzae.
- Author
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Islam, Md. Rashidul, Hirata, Hisae, Tsuge, Seiji, and Tsuyumu, Shinji
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RICE diseases & pests , *XANTHOMONAS , *PLANT diseases , *MUTAGENESIS , *CULTIVARS - Abstract
Xanthomonas oryzae pv. oryzae ( Xoo) is the causal agent of bacterial leaf blight, a serious disease of rice. Here, we isolated a pathogenicity-deficient mutant of Xoo strain T7174R [a rifampicin-resistant derivative of T7174 (MAFF311018)] produced by in vivo insertion mutagenesis using the EZ::TNâ„¢ transposon system. This mutant, 74M2, was significantly reduced in virulence on rice cultivar IR24. From sequence analyses, the region with the EZ::TN transposon insertion was found to be in ORF XOO1662, one of the leucine-rich proteins found in the genome database for MAFF311018, which we have named lrpX. In planta growth of 74M2 was also slower than that of the wild type. A complementation construct for 74M2 restored both virulence and in planta growth to wild-type levels. The promoter region of lrpX contained a consensus plant-inducible promoter (PIP)-box (i.e., TTCGC-N15-TTCGC) commonly found in HrpX (an AraC-type transcriptional regulator)-regulon in xanthomonads. The HrpXo (HrpX of Xoo)-dependent expression of lrpX was confirmed using the fusion construct with lrpX:: GUS in hrp-inducing minimal medium (XOM2). The expression of lrpX was predicted to be self-regulated by its own translation product by directly binding to its own promoter. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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