Elevation of Diacylglycerol during the Early Stage of Elicitor-signal Transduction in Pea(Pisum sativum).

Potentiation of Phytoalexin Accumulation in Elicitor-treated Epicotyls of Pea (Pisum sativum) by a Diacylglycerol Kinase Inhibitor

“…Recent reports from the authors' laboratory have indi-cated that the key events in signal transduction for phytoalexin accumulation in pea tissues exposed to fungal elicitor include ion¯uxes (Amano et al, 1997), an activation of protein kinases (Shiraishi et al, 1990) and phosphorylation of phosphatidylinositols and the subsequent activation of phospholipase C (PLC) (Toyoda et al, 1992(Toyoda et al, , 1993. Furthermore, the elicitor induced increased levels of diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP 3 ) within a few minutes of the start of the elicitor treatment in pea epicotyls (Toyoda et al, 1993(Toyoda et al, , 1998, followed by a marked accumulation of phenylalanine ammonia-lyase (PAL), a key enzyme in the biosynthetic pathway to the pea phytoalexin pisatin (Yamada et al, 1989). However, an inhibitor of PLC, neomycin, appreciably prevented the elicitor-induced increase in DAG and IP 3 , resulting in inhibition of phytoalexin accumulation in pea tissues, and also conditioned the tissues to be susceptible even against avirulent pathogens (Toyoda et al, 1993).…”

Potentiation of Phytoalexin Accumulation in Elicitor‐treated Epicotyls of Pea (Pisum sativum) by a Diacylglycerol Kinase Inhibitor

“…Recent reports from the authors' laboratory have indicated that the key events in signal transduction for phytoalexin accumulation in pea tissues exposed to fungal elicitor include ion fluxes (Amano et al., 1997), an activation of protein kinases (Shiraishi et al., 1990) and phosphorylation of phosphatidylinositols and the subsequent activation of phospholipase C (PLC) (Toyoda et al., 1992, 1993). Furthermore, the elicitor induced increased levels of diacylglycerol (DAG) and inositol 1,4,5‐trisphosphate (IP 3 ) within a few minutes of the start of the elicitor treatment in pea epicotyls (Toyoda et al., 1993, 1998), followed by a marked accumulation of phenylalanine ammonia‐lyase (PAL), a key enzyme in the biosynthetic pathway to the pea phytoalexin pisatin (Yamada et al., 1989). However, an inhibitor of PLC, neomycin, appreciably prevented the elicitor‐induced increase in DAG and IP 3 , resulting in inhibition of phytoalexin accumulation in pea tissues, and also conditioned the tissues to be susceptible even against avirulent pathogens (Toyoda et al., 1993).…”