DIFFERENTIAL PROTEIN ACCUMULATION IN ZEATIN-AND 2,4-D-TREATED CELLS OF CATHARANTHUS-ROSEUS - CORRELATION WITH INDOLE ALKALOID BIOSYNTHESIS

In order to identify molecular markers of the inhibiting action of aux in and those of the promotive action of cytokinin on indole alkaloid a ccumulation in a 2,4-D-dependent Catharanthus roseus cell line, protei n changes were analyzed by two-dimensional polyacrylamide gel electrop horesis. Cells were grown either on hormone-free medium or in media in which 2,4-dichlorophenoxyacetic acid (2,4-D), zeatin or 2,4-D plus ze atin were added on the 3rd day; die total polypeptide patterns were co mpared at the end of the 1st, 2nd and 4th day of hormonal treatments. The patterns were very similar, but a few polypeptides appeared to be hormone-regulated; they were classified in six groups, according to th eir expression patterns. Emphasis has been set on a group of polypepti des, die levels of which were negatively controlled by 2,4-D and posit ively controlled by zeatin, which might be implicated in the regulatio n of alkaloid metabolism. These polypeptides were not modified in a fu lly-hormone independent line which did not accumulate alkaloid after t reatment by zeatin.