Reducing jasmonic acid levels causes ein2 mutants to become ethylene responsive

It has previously been shown that jasmonic acid affects the ethylene signaling pathway. EIN2 is a central component of ethylene signaling that is downstream of the receptors. EIN2 has previously been shown to be required for ethylene responses. We found that reducing jasmonic acid levels, either mutationally or chemically, caused ein2 ethylene-insensitive mutants to become ethylene responsive. This effect was not seen with the ethylene-insensitive etr1-1 mutants that affect receptor function. Based upon these results, we propose a model where jasmonic acid is inhibiting ethylene signal transduction down-stream of the ethylene receptors. This may involve an EIN2-independent pathway.

► Ethylene-insensitive ein2 mutants respond to ethylene when crossed with dde2-2.
► Phenidone also causes ein2 mutants to be ethylene responsive.
► A model is presented positing that JA inhibits ethylene signaling.
► This inhibition occurs down-stream of the receptors.
► There may be an EIN2-independent pathway.