Timing of Changes in Protein Synthesis Pattern in Elicitor-Treated Cell Suspension Cultures of Parsley ( Petroselinum crispum)

The timing o f changes in the protein synthesis pattern o f elicitor-treated, [35S]methioninelabelled parsley cells ( Petroselinum crispum) was analyzed by two-dimensional gel electropho­ resis. Five groups were distinguished from a large number o f elicitor-responsive as well as un­ responsive proteins. Two groups were synthesized de novo either early or late after elicitor ap­ plication; two other groups were strongly reduced in their rates o f synthesis either early or late after elicitor application; and one group was not appreciably affected at all. The elicitor-induced changes altered the total protein composition considerably. A few selected, induced pro­ teins were functionally identified. These included two early induced enzymes, phenylalanine ammonia-lyase (PAL) and 4-coumarate:CoA ligase (4CL), and a late induced enzyme, a bergaptol O-methyltransferase (BMT) which is specifically involved in the biosynthesis o f furanocoumarin phytoalexins. The biological significance o f the observed differential timing o f changes in protein synthesis rates is discussed.