Abstract
From a cDNA library of cultured Glycyrrhiza echinata L. (Fabaceae) cells treated with yeast extract (YE) elicitor, eight cytochrome P450 (P450) fragments (Ge-1 to 8) were isolated using the PCR method based on conserved sequences of P450s. Comparison of amino acid sequences revealed that two of the fragments (Ge-1 and 2) belong to the CYP73 family encoding trans-cinnamic acid 4-hydroxylase. Ge-4 had 63% identity with the sequence included in CYP93, which has recently been reported to be induced by methyl jasmonate in soybean cells (Suzuki et al., FEBS Lett., 383 (1996) 83–86), and Ge-6 and 7 were highly homologous to the partial sequence of CYP84 encoding ferulic acid 5-hydroxylase of Arabidopsis thaliana (Meyer et al., Proc. Natl. Acad. Sci. USA, 93 (1996) 6869–6874). Others (Ge-3, 5 and 8) displayed homology less than 43% with known plant P450s. A full-length cDNA (CYP73A14) containing Ge-1 sequence was isolated from the cDNA library, and its amino acid sequence showed 91–93% identity with CYP73 of other leguminous plant species. Northern blot analysis of mRNAs of G. echinata cells indicated that CYP73 (Ge-1 and 2) genes were transcribed at the early stages post-elicitation (<10 h). The transcription level of the Ge-1 gene was much higher than that of Ge-2. Transcription of Ge-3, 5, 6 and 7 was also activated by elicitation, but no clear signal from Ge-4 and 8 was observed. When total RNAs of cultured cells of Medicago sativa were analyzed by Northern blotting, transcripts hybridized with G. echinata cDNA clones containing Ge-1, 3, 5 and 6 sequences could be detected. Possible involvement of cloned P450s in elicitor-induced phenylpropanoid/flavonoid biosynthesis is discussed.
Published Version
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