Abiotic stresses activate a MAPkinase in the model grass species Lolium temulentum

Forage and turf grasses are utilized in diverse environments that expose them to a variety of abiotic stresses, however very little is known concerning the perception or molecular responses to these various stresses. In the model grass species Lolium temulentum, a 46 kDa mitogen-activated protein kinase (MAPK) was activated in the leaf within 10 min of exposing the roots to salt stress. When plants were subjected cold stress, no significant activation of the MAPK was observed. However, the 46 kDa MAPK was rapidly activated in the leaves of plants within 3 min of exposure to heat stress. Previously, mechanical wounding has been shown to rapidly activate a 46 kDa and a 44 kDa MAPK in L. temulentum. The wound activation of the MAPKs was delayed and diminished in plants undergoing cold treatment. In plants subjected simultaneously to 40 °C and wounding, the activation of the 46 kDa MAPK was enhanced. However if plants were subjected to heat and cold stress for more than 2 h or exposed to 300 mM NaCl for 24 h prior to wounding, the wound activation of the 46 kDa and a 44 kDa MAPKs were significantly inhibited. These results suggest that the 46 kDa MAPK plays a role in the response to various environmental stimuli.