Characterization of three protein phosphatase type 2C genes from the ice plant (Mesembryanthemum crystallinum)

Abstract

The common ice plant is a halophyte and a model plant for salt tolerance. We have studied on the ice plant for understanding molecular mechanisms of salt tolerance, especially focusing on genes encoding protein phosphatases type 2C (PP2C) that are thought to be negative regulators of the MAPK signal transduction pathway. In this study, we have cloned 11 PP2C genes from the ice plant and named MPC1~11. Gene expression of MPC2 and MPC8 are up-regulated and that of MPC6 is down-regulated by salt stress. Since we have not yet established a transformation method of the ice plant, we introduced MPC2, MPC6 or MPC8 genes into Arabidopsis plants under 35S promoter, allowing over-expression of these heterogous genes to investigate functions of these PP2C genes concerning the signal transduction pathways against salt tolerance.