Transient expression in electroporated pea protoplasts: Elicitor responsiveness of a phenylalanine ammonia-lyase promoter.

High yields of viable pea protoplasts were produced from suspension cultured cells and the conditions for the optimum transient expression of the chloramphenicol acetyltransferase (CAT) gene fused to the CaMV 35S promoter after electroporation were investigated. Conditions for elicitor induction of a member of the phenylalanine ammonia-lyase (PAL) gene family in pea was also investigated using a chimeric gene carrying 480 bp of the putative promoter region of gPAL1 connected to bacterial cat gene and nos terminator. CAT activity was considerably induced by the treatment with fungal elicitor (>100 μg/ml glucose equivalent) isolated from Mycosphaerella pinodes, a pea pathogen.