Characterization of the structure and determination of mRNA levels of the phenylalanine ammonia-lyase gene family from Populus kitakamiensis

We isolated two new PAL genes, palg2b and palg4, from Populus kitakamiensis. palg2a and palg2b are clustered and palg2b encodes a polypeptide of 710 amino acids. The nucleotide sequence in the coding region of palg2b was 94.6% identical to that of palg2a. The promoter regions of palg1, palg2a and palg2b have several elements conserved among many phenylpropanoid biosynthetic genes. We measured the mRNA levels of the four PAL genes by S1 mapping using total RNA from stem tissues developing secondary xylem. Results showed that the transcript level of palg2b was higher than that of the other PAL genes.