Cinnamyl-alcohol dehydrogenase, a molecular marker specific for lignin synthesis: cDNA cloning and mRNA induction by fungal elicitor.
Cinnamyl-alcohol dehydrogenase (CAD; EC 1.1.1.195) catalyzes the final step in a branch of phenylpropanoid synthesis specific for production of lignin monomers. We have isolated a full-length cDNA clone encoding CAD, as a molecular marker specific for lignification, by immunoscreening a lambda gt11 library containing cDNAs complementary to mRNA from elicitor-treated cell cultures of bean (Phaseolus vulgaris L.). The clone comprises a single long open reading frame of 1767 base pairs, 31 base pairs of 5' leader, and 152 base pairs of 3' untranslated sequence. The deduced 65-kDa CAD polypeptide has several features that are strongly conserved in alcohol dehydrogenases. Addition of fungal elicitor to cell cultures stimulates CAD transcription, which leads to a remarkably rapid, but transient, accumulation of CAD mRNA, with no detectable lag and maximal levels after 1.5 hr. Southern blot analysis of bean genomic DNA indicates that elicitor-induced CAD is encoded by a single gene. The regulatory significance of the rapid activation of this CAD gene and the possible existence of a second, divergent CAD gene involved in lignification during xylogenesis are discussed.
D000429:Alcohol Oxidoreductases / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D007887:Fabaceae; D005656:Fungal Proteins / Q000494:pharmacology; D005786:Gene Expression Regulation; D008031:Lignin / Q000096:biosynthesis*; D003904:Mitosporic Fungi; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010946:Plants, Medicinal; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic
D005656:Fungal Proteins; D012333:RNA, Messenger; D008031:Lignin; D004247:DNA; D000429:Alcohol Oxidoreductases; C018656:cinnamyl alcohol dehydrogenase