Evidence of phosphorylated phosphatidylinositols in the growth cycle of suspension cultured plant cells.

Suspension cultured cells of Catharanthus roseus rapidly consume the inorganic phosphate of the medium and incorporate about 25% of it into their phospholipids. By three different methods of analysis it was shown that from these plant cells phosphorylated phosphatidylinositol species can be extracted; the mono- and diphosphorylated species were detected in amounts of about 7 and 1%, respectively, of the phosphatidylinositol fraction. Autoradiography of 32P-labeled phospholipids showed that especially the amount of diphosphorylated species varies with the growth cycle of the suspension culture indicating that also in the higher plant cell this phospholipid turnover may play a role in the regulation of proliferation.