Nicotiana attenuata protein kinases mediate plant growth and resistance to insect herbivores Protein kinases modulate developmental and adaptation processes in the plant kingdom. While MAPK signaling has been intensively studied for the involvement in growth defense and growth regulation more and more studies have shown that CDPKs also function in these physiological processes. N. attenuata is an annual solanaceous plant which germinates only after fire. In its natural habitat in the Great Basin Desert in Utah USA after being attacked by the specialist tobacco hornworm Manduca sexta N. attenuata has developed many specific and fine tuned responses to cope with herbivore challenges. It has been shown that two MAPKs NaSIPK and NaWIPK are involved in defense against M. sexta attack by controlling the plant hormone jasmonic acid (JA). The burst of JA after herbivore recognition is important to induce defense responses such as the production of small secondary metabolites (e.g. nicotine) and defensive proteins – trypsin proteinase inhibitor (TPI). MAPKs are the last element in a MAPK cascade: MAPKKKs activate MAPKKs which in turn phosphorylate MAPKs. In order to investigate the function of MAPK cascades in plant herbivore interactions using N. attenuata and M. sexta as the model system I studied the function of five MAPKKs in plant defense against herbivores.