Are Polyphosphoinositides Involved in Signal Transduction of Elicitor-Induced Phytoalexin Synthesis in Cultured Plant Cells?

The phospholipids of cultured parsley and soybean cells were labelled with myo-[2-3H]inositol, [2-3H]glycerol or [32P]orthophosphate. By oneand two-dimensional chromatographic compari­ son of the labelled phospholipids with reference substances, the presence of l-(3-sn-phosphatidyl)-D-myo-inositol 4-phosphate and l-(3-sn-phosphatidyl)-D-myo-inositol 4,5-bisphosphate was demonstrated in these cultures. These results were corroborated by analysis of the deacylation products. Cells were labelled with either myo-[2-3H]inositol, [2-3H]glycerol or [32P]orthophosphate and subsequently challenged with elicitor for various lengths of time. Radioactivity in individual phosphoinositides from these cells was determined. No significant influence of elicitorchallenge of either soybean or parsley cells on incorporation of 3H or 32P into polyphospho­ inositides was found between 0.5 and 20 min after elicitor addition.