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Molecular characterization and functional expression of dihydroxypterocarpan 6a‐hydroxylase, an enzyme specific for pterocarpanoid phytoalexin biosynthesis in soybean ( Glycine max L.)
Author(s) -
Schopfer Christel R,
Kochs Georg,
Lottspeich Friedrich,
Ebel Jürgen
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00866-7
Subject(s) - phytoalexin , elicitor , isoflavonoid , biochemistry , enzyme , complementary dna , biology , glycine , inducer , cytochrome p450 , biosynthesis , microbiology and biotechnology , gene , amino acid , flavonoid , resveratrol , antioxidant
Four cytochrome P450‐dependent enzymes, among them dihydroxypterocarpan 6a‐hydroxylase (D6aH), are specifically involved in the elicitor‐inducible biosynthesis of glyceollins, the phytoalexins of soybean. Here we report that CYP93A1 cDNA, which we isolated previously from elicitor‐induced soybean cells, codes for a protein with D6aH activity. Analysis of the catalytic properties of recombinant CYP93A1 expressed in yeast, its NADPH dependency, stereoselectivity and high substrate affinity confirmed that D6aH is the physiological function of CYP93A1. It thus represents the first isoflavonoid‐specific CYP to be characterized at the molecular level. In elicitor‐treated soybean cells producing phytoalexins, increases in D6aH activity were correlated with elevated transcript levels which indicates that expression of the enzyme is regulated at the level of transcription. Therefore, CYP93A1 cDNA can be used as a specific molecular marker for the inducible defense response against pathogen attack.