Potentiation of phytoalexin accumulation in elicitor-treated epicotyls of pea (Pisum sativum) by a diacylglycerol kinase inhibitor

When epicotyl tissues of pea were treated with a diacylglycerol (DAG) kinase inhibitor (R59022), enhanced induction of the phytoalexin accumulation occurred which was induced by fungal elicitor. The marked induction was associated with a sustained accumulation of phenylalanine ammonia-lyase (PAL)-mRNA and the consequent increase in PAL activity. These results suggest that inhibition of DAG breakdown leads to increased induction of phytoalexin accumulation and support the hypothesis that DAG kinase negatively regulates the signal transduction.