Differential regulation of phenylalanine ammonia‐lyase genes during anthocyanin synthesis and by transfer effect in carrot cell suspension cultures

Phenylalanine ammonia‐lyase (PAL; EC 4.3.1.5) catalyses the first step in the phenylpropanoid pathway and is induced during differentiation and by various stimuli. In carrot ( Daucus carota L. cv. Kurodagasun) suspension culture cells, PAL is slowly induced during anthocyanin synthesis which occurs in a medium lacking 2,4‐dichlo‐rophenoxyacetic acid and is also induced rapidly and transiently by transferring and diluting cells to fresh medium. Analyses of nucleotide sequences derived from PAL cDNAs revealed that the PAL mRNAs induced by transfer were transcribed from different carrot PAL genes than the PAL mRNAs induced during anthocyanin synthesis. Northern blotting using probes derived from 3’non‐coding regions for PAL cDNAs confirmed that different PAL genes were induced during anthocyanin synthesis and after transfer. Induction of different PAL genes occurs in response to differences in the induction trigger.