Protein tyrosine phosphatases involved in signaling of the ABA-induced H_2O_2 generation in guard cells of Vicia faba L.

摘要

Although protein tyrosine phosphatases (PTPases) play an important role in signal transduction in animal cells, little is known about the function of PTPases in higher plants. Hydrogen peroxide (H_2O_2) and mitogen-activated protein kinases (MAPKs) are the critical components of ABA signaling pathway in guard cells. PTPase is an important regulator of MAPK, which is believed to mediate ABA-induced H_2O_2 generation in guard cells of Vicia faba L, Here, we investigate the possible role of PTPases in stomatal movement process. Phenylarsine oxide (PAO), a specific inhibitor of PTPases, could prevent ABA or H_2O_2-induced stomatal closure of View faba L; furthermore, it could promote opening of the stomata closed by ABA or H_2O_2. The activity of PTPases can be effectively inhibited by PAO and H_2O_2. DTT had no effect on the PAO-induced inhibition of PTPases activity, but it could relieve the inhibition of H_2O_2 on PTPases activity. PAO could also inhibit the ABA-induced H_2O_2 generation in guard cells of View faba L. These results suggested that PTPases is a critical signaling component in ABA-induced stomatal closure, and serve as targets for H_2O_2 lying on the signaling pathways downstream of ABA induced H_2O_2 generation.