Abstract
PSK is a secreted peptide originally found in plant cell culture. This peptide induces the plant cell proliferation and/or differentiation in vitro, but their function in intact plants remains to be elucidated. A 120-kD leucine-rich repeat receptor kinase, specifically interacting with PSK, has been purified from carrot plasma membranes using ligand-based affinity chromatography. Three orthologs of this LRR-RLK named AtPSKR1, AtPSKR2 and AtPSKR3 have been identified in Arabidopsis. We observed a significant increase in PSK binding activity in the membrane fractions of the transgenic callus overexpressing AtPSKR1, confirming that AtPSKR1 actually interacts with PSK. Growth of AtPSKR1 knockout plants is comparable to WT in vitro but is suppressed in soil culture, indicating that AtPSKR1 knockout plants are sensitive to the environmental stress. PSK signaling may be involved in the re-construction of the tissue in response to wounding caused by the environmental stress.
