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Cytochrome P450 mono-oxygenases (P450s) are a superfamily of heme-dependent enzymes which play important roles in almost all of organisms. Based on rice genome database, a gene encoding a rice cytochrome P450 mono-oxygenase was cloned and sequenced (GenBank accession no. AY579214). The coding region of the gene was 1530 nucleotides in length and encoding a protein with 510 amino acid residues in length. Sequence analyses indicated that the cytochrome P450 corresponds to an ent-kaurene oxidase (KO) like protein, which is likely to be involved in phytoanticipins/phytoalexins biosynthesis. Southern blots analysis suggested that there are at least four similar genes encoding ent-kaurene oxidase or ent-kaurene oxidase like proteins in rice genome. Therefore, the gene reported in this paper was named OsKOS1. RT-PCR analysis showed that OsKOS1 was expressed in vegetative organs and reproductive organs, but at a higher level in vegetative organs. The expression level of OsKOS1 in RDV (rice dwarf virus)-infected plants was much lower than that in healthy plants, indicating that OsKOS1 is likely to be involved in defending RDV. |
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Keywords:cytochrome P450, ent-kaurene oxidase like protein, phytoanticipin/phytoalexin, rice |
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