Regulatory functions and molecular mechanisms of ethylene receptors and receptor-associated proteins in higher plants

The gaseous plant hormone ethylene plays crucial roles in many aspects of plant growth, development and stress responses. Ethylene signaling is initiated upon its binding to the ethylene receptors. Since the cloning of the first ethylene receptor ETR1 from Arabidopsis, efforts have been made in elucidation of ethylene receptor organization, signaling, and receptor-interacting proteins in higher plants. However, the update information about the ethylene receptors, receptor interacting proteins and their regulatory functions and molecular mechanisms has not been well scrutinized and discussed. Critical questions regarding the confusing or contradictory responses and phenotypes have been barely answered. This article gave an overview of the current progress in the identification, regulatory functions and possible molecular mechanisms of the ethylene receptors and receptor-interacting proteins in ethylene signaling and responses. The novel findings of the crosstalk between ethylene signaling and the other plant hormones were integrated into the review article. Questions and future research directions about the key components in the regulation of ethylene signaling were also proposed and emphasized. The update message may greatly facilitate comprehensive understanding of the ethylene signaling and molecular regulations in higher plants.