Role of the pepper cytochrome P450 gene CaCYP450A in defense responses against microbial pathogens.
Plant cytochrome P450 enzymes are involved in a wide range of biosynthetic reactions, leading to various fatty acid conjugates, plant hormones, or defensive compounds. Herein, we have identified the pepper cytochrome P450 gene CaCYP450A, which is differentially induced during Xanthomonas campestris pv. vesicatoria (Xcv) infection. CaCYP450A contains a heme-binding motif, PXFXXGXRXCXG, located in the C-terminal region and a hydrophobic membrane anchor region at the N terminal. Knock-down of CaCYP450A by virus-induced gene silencing (VIGS) led to increased susceptibility to Xcv infection in pepper. CaCYP450A-overexpressing Arabidopsis plants exhibited lower pathogen growth and reduced disease symptoms, and they were more resistant to Pseudomonas syringae pv. tomato (Pst) and Hyaloperonospora arabidopsidis than wild-type plants. Overexpression of CaCYP450A also enhanced H(2)O(2) accumulation and cell death. However, CaCYP450A Arabidopsis ortholog CYP94B3 mutants showed enhanced susceptibility to virulent Pst DC3000, but not to avirulent Pst DC3000 avrRpm1 or virulent H. arabidopsidis infection. Taken together, these results suggest that CaCYP450A is required for defense responses to microbial pathogens in plants. The nucleotide sequence data reported here has been deposited in the GenBank database under the accession number HM581974.
Hwang
In Sun
IS
Laboratory of Molecular Plant Pathology, School of Life Sciences and Biotechnology, Korea University, Anam-dong, Sungbuk-ku, Seoul, 136-713, Korea.
Hwang
Byung Kook
BK
D000595:Amino Acid Sequence; D002212:Capsicum / Q000201:enzymology* / Q000235:genetics / Q000382:microbiology; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000235:genetics*; D055785:Gene Knockdown Techniques; D017343:Genes, Plant; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D016959:Xanthomonas campestris / Q000472:pathogenicity*
D003577:Cytochrome P-450 Enzyme System