A transient increase of phenylalanine ammonia-lyase transcript in kinetin-treated tobacco callus.

In tobacco cell culture (Nicotiana tabacum L. "Bright Yellow" T-13), phenylalanine ammonia-lyase (PAL) activity was induced in response to an exogenously added kinetin. RNA blot hybridization analysis showed that a single species of PAL transcript 2.9-kb in size was detected using the PAL cDNA cloned from kinetin-treated cells. The cellular content of this transcript increased transiently (2.5-fold) 4 h after the addition of kinetin followed by an increase in PAL enzyme activity at 16 h.