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RESEARCH PRODUCT

Changes in lipid composition in tobacco cells treated with cryptogein , an elicitor from Phytophthora cryptogea

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Abstract Changes in lipid composition occurred when tobacco cells (Nicotiana tabacum var. Xanthi) were treated with cryptogein, a proteinaceous elicitor from Phytophthora cryptogea. The most striking change was an increase in acylated steryl glycosides and steryl esters levels, certainly resulting from the glycosylation and/or esterification of free sterols. Moreover, in vivo pulse-labelling experiments with [14C]acetate also showed that a progressive decline in the incorporation rate of [14C]acetate into free sterols started with the induction of sesquiterpenoid synthesis and lasted when sesquiterpenoid synthesis stops. This phenomenon was accompanied by a significant increase in the synthesis rate of phosphatidylethanolamine occuring after a period of 12 h (80% of [14C]incorporated into lipids was found in PE). These pulse-labelling experiments also indicated a transient neosynthesis of high levels of acylated steryl glycosides and steryl esters in elicited cells. These results demonstrated that glycosylation and/or esterification of sterols (preexistent or neosynthetised) is an initial event among plant cell responses associated with the hypersensitive reaction.