Regulation of polyphosphoinositide metabolism in pea plasma membranes by elicitor and suppressor from a pea pathogen, mycosphaerella pinodes

Effects of the elicitor and the suppressor from a pea pathogen, Mycosphaerella pinodes, on polyphosphoinositide metabolism in pea plasma membranes were examined in vitro. Lipid phosphorylation in the isolated pea plasma membrane was drastically stimulated by the elicitor, but markedly inhibited by the suppressor. A similar inhibitory effect was observed by the treatment with orthovanadate or K-252a that blocked pisatin production induced by the elicitor. Neomycin, an aminoglycoside antibiotic that interacts with the polyphosphoinositide metabolism, also affected the lipid phosphorylation in vitro and blocked the elicitor-induced accumulation of pisatin in vivo. These results suggest that rapid changes of polyphosphoinositide metabolism in pea plasma membranes is one of indispensable processes during the elicitation of defense responses.