Phosphatidylinositol 3-phosphate is required for abscisic acid-induced hydrogen peroxide production in rice leaves

Rice leaves produce H2O2 in response to abscisic acid (ABA), which results in induction of senescence and accumulation of NH4+. The upstream steps of the ABA-induced H2O2 production pathway in rice leaves remain largely unclear. In animal cells, H2O2 production in neutrophils is activated by phosphatidylinositol 3-phosphate (PI3P), a product of phosphatidylinositol 3-knase (PI3K). In the present study, we examined whether PI3P plays a role in H2O2 production in rice leaves exposed to ABA. We found that PI3K inhibitors LY 294002 (LY) or wortmannin (WM) inhibited ABA-induced H2O2 production, senescence and NH4+ accumulation. Hydrogen peroxide almost completely rescued the inhibitory effect of LY or WM. It appears that PI3P plays a role in ABA-induced H2O2 production, senescence, and NH4+ accumulation in rice leaves.