Abstract

Cloning, sequencing, and characterization of the isoflavone synthase gene (2-hydroxyisoflavone synthase;IFS) from Pueraria candollei var. mirifica were carried out in this study. The full-length open reading frame (ORF) of the P. candollei var. mirifica IFS gene or PcmIFS was obtained by reverse transcription polymerase chain reaction (RT-PCR). Nucleotide sequence of PcmIFS was 1,566 bp long, encoded for 521 amino acid residues with the relative molecular mass of 58.9 kDa. The pI value of the PcmIFS gene product was 8.9 and all of the main conserved motifs that are essential for IFS activities were found. The deduced amino acid sequence of the PcmIFS-encoded protein showed high degree of identity to those of IFS proteins fromPueraria montana var. lobata, Glycine max, Glycine soja, and Pisum sativum. Southern blot analysis indicated that the PcmIFS gene belonged to a multigene family. The expression of PcmIFS was detected in leaf, stem, and root of the plant and its expression levels was induced by both low and high temperature stresses as well as by UV-B and wounding treatments.

Key words: Isoflavone synthase, isoflavones, Pueraria candollei var. mirifica, molecular cloning.