The jasmonate pathway: the ligand, the receptor and the core signalling module

Jasmonates regulate specific developmental processes and plant adaptation to environment by controlling responses to external biotic or abiotic stimuli. The core events of jasmonate signalling are now defined. After hormone perception by SCFCOI1, JAZ (JAsmonate ZIM domain) repressors are targeted for proteasome degradation, releasing MYC2 and de-repressing transcriptional activation. JAZs are homomeric and heteromeric proteins and have been instrumental in recent advances in the field, such as the identification of COI1 as a critical component of the jasmonate receptor and the discovery of the bioactive jasmonate in Arabidopsis, (+)-7-iso-JA–Ile. Small changes in jasmonate structure result in hormone inactivation and might be the key to switching-off signalling for specific responses to stimulus and for long-distance signalling events.