Linnean Centre Seminar

Summary:

Plants respond to mechanical stimulations such as wind, rain, touching or wounding to safeguard their development and survival. Rapid activation of downstream Mitogen Activated Protein Kinases (MAPKs) by mechanical stimuli was already reported 25 years ago, but the upstream regulatory mechanism and function of this phenomenon has remained unknown. Here we report that mechanical stimulation activates a MAPKKK-MKK-MPK cascade within 60 seconds, which leads to the induction of nearly 800 genes, encompassing the majority of the core early touch response. Most of these genes overlap with the touch-responsive genes regulated by CAMTA transcription factors, exposing an interplay between MAPKs and CAMTA. Furthermore, we found that loss of MKKs leads to global impairment of touch-regulated protein phosphorylation, demonstrating they are crucial regulators of touch-induced phosphorylation. On the other hand, we could not find clear evidence for a role of phosphorylation in the early activation of the touch-induced jasmonic acid (JA) signalling pathway, nor did loss of JA affect the overall early touch phosphoproteome. Lastly, we found that loss of MAPKKK and MKK function reduces thigmomorphogenesis responses, underlining the importance of the identified MAPK cascade for steering plant growth during stress.