The Roles Of Phospholipase C And D In Xylanase-Induced Defense Responses In Suspension-Cultured Rice Cells

The paper studied the roles of phospholipase C (PLC) and phospholipase D (PLD) in the resistance to xylanase in suspension-cultured rice cells.We used suspension-cultured rice cells which were trained for 3 to 5 days for materials, and then treated with xylanase(final concentration 100μg/ml) and the concentration of cells was 0.05g/ml. Then we found that the activity of PLDa and PLDβwere both activated at 1h after treatment. And the activity of PLDa was activated at 2h again, and then back to normal level. But the activity of PLDβgradually reduced with the extension of treatment time and even below the normal level. In the RT-PCR experiments, we found that the expression of OsPLDal didn't change when cells were treated with xylanase, and was similar with the control team. But the variation tendency of the OsPLDal expression was the same as its activity, which expressed quickly at early process and then gradually reduced. Furthermore, the expression of OsPI-PLC1 gradually increased and was significantly higher than the controls.Then we detected the changes of reactive oxygen species(ROS) in xylanase-treated cells. The results showed the content of H2O2 and O2 were both changed. The content of H2O2 had two peaks obviously, and the accumulation of O2 went up constently, but the growth rate of O2 also had two peaks which appeared at lh and 4h after treatment. Next, we treated cells with different concentrations of PA, and the results indicated the content of ROS gradually went up with the increasing of concentration of PA. These indicated that the xylanase-induced oxidative burst was related to the activity of PLC and PLD. Soon afterwards we did disproof. Before we treated cells with xylanase, we added 1-Butanol(the inhibitor of PLD) and Neomycin Sulfate(the inhibitor of PLC) respectively, Oxidative burst of inhibitor-treated cells was inhibited.We used RT-PCR technic to study the relation between the expression of disease resistance genes PRIOa and OsChit-1 and the activity of PLD and PLC. Xylanase could induce the expression of PRIOa and OsChit-1. But PLC and PLD could only control and regulate the expression of PR 10a, but had no relation to OsChit-1.Xylanase could induce hypersensitive cell death and programmed cell death(PCD). But they were both eased off when the activity of PLC and PLD were inhibited.1-Butanol could suppress the biosynthesis of xylanase-induced sakuranetin, but not Neomycin Sulfate. It meant PLD could control and regulate the biosynthesis of phytoalexin, but not PLC.From the above, xylanase could induce the activity of PLDa and PLDβand the expression of OsPLDβ1 and OsPI-PLC1, but had no effect on the expression of OsPLDal; PLC and PLD controlled and regulated the xylanase-induced ROS burst by PA; PLC and PLD had effect on the expression of partial disease resistance genes; Inhibited the activity of PLC and PLD could anesis the xylanase-induced hypersensitive cell death and programmed cell death(PCD); PLD participated in controlling the biosynthesis of phytoalexin(sakuranetin).