Cloning and expression analysis of phenylalanine ammonia-lyase (PAL) gene family and cinnamate 4-hydroxylase (C4H) from Dryopteris fragrans

Abstract

Phenylalanine ammonia-lyase (PAL) and cinnamate 4-hydroxylase (C4H) are the first and second key enzymes of the phenylpropanoid pathway. Systematic analysis of the DfPAL gene family and DfC4H have not been performed in Dryopteris fragrans (L.) Schott. To date, PAL and C4H genes have been less extensively studied in monilophytes than in angiosperms. Here we report the identification of three DfPAL and DfC4H fragments using cDNA cloning and sequencing. Bioinformatics and phylogenetic analyses showed that DfPAL1 and DfPAL2 were quite similar at the amino acid level (94.88%), whereas DfPAL3 was relatively low similar to both of the other paralogs. Some important functional domains were conserved in three DfPAL and DfC4H genes. DfPAL3 and DfC4H were highly expressed in gametophytes and petioles of D. fragrans, DfPAL1 had the highest expression in petioles, and DfPAL2 had low expression in leaves and petioles. Only DfPAL2 and DfC4H were induced with 4°C, 35°C, and UV treatments, but the time responses were different. These results suggest complexity of the DfPAL- and DfC4H-associated metabolic network in D. fragrans. The results provide a basis for elucidating the role of DfPAL and DfC4H genes in the biosynthesis of bioactive compounds.