New perspective in ethylene signaling

Key steps in understanding ethylene signaling have come from studying Arabidopsis mutants. The mechanisms of receptor signal output are still poorly understood and the discovery of new components has increased the apparent complexity. Not all receptors are equivalent and some appear to have unique functions. There are multiple CTR-like proteins in tomato, which interact with more than one receptor. Focusing on mutants of the Arabidopsis triple response, which is primarily a growth response, may not uncover the complete range of components involved in developmental responses to ethylene and it is also possible there are real differences between species.