Mechanistic Insights in Ethylene Perception and Signal Transduction

Abstract

The gaseous hormone ethylene profoundly affects plant growth, development, and stress responses. Ethylene perception occurs at the endoplasmic reticulum membrane, and signal transduction leads to a transcriptional cascade that initiates diverse responses, often in conjunction with other signals. Recent findings provide a more complete picture of the components and mechanisms in ethylene signaling, now rendering a more dynamic view of this conserved pathway. This includes newly identified protein-protein interactions at the endoplasmic reticulum membrane, as well as the major discoveries that the central regulator ETHYLENE INSENSITIVE2 (EIN2) is the long-sought phosphorylation substrate for the CONSTITUTIVE RESPONSE1 protein kinase, and that cleavage of EIN2 transmits the signal to the nucleus. In the nucleus, hundreds of potential gene targets of the EIN3 master transcription factor have been identified and found to be induced in transcriptional waves, and transcriptional coregulation has been shown to be a mechanism of ethylene cross talk.

Ethylene Signaling Modulates Cortical Microtubule Reassembly in Response to Salt Stress

“…The phytohormone ethylene plays a crucial role in the regulation of diverse stress 97 responses, including salt stress (Peng et al, 2014;Pan et al, 2016 EIN3-like (EIL)1 (Merchante et al, 2013;Ju et al, 2015;Yang et al, 101 2015). EIN2 is an essential positive regulator of ethylene signaling, and the null seedlings are hypersensitive to salt stress, thus suggesting that EIN3 and EIL1 are 112 positive regulators of the salt-stress response in plants (Lei et al, 2011;Peng et al, 113 2014 plants (Shi et al, 2012).…”

Ethylene promotes cadmium‐induced root growth inhibition through EIN3 controlled XTH33 and LSU1 expression in Arabidopsis

“…Ethylene is a gaseous phytohormone that plays vital roles in numerous cellular and developmental processes and also plays key roles in plant responses to biotic and abiotic stresses, triggering a wide range of physiological and morphological responses (Dubois, Van Der Broeck, & Inze, 2018;Guo & Ecker, 2004;Yoo, Cho, & Sheen, 2009). In Arabidopsis, ethylene signalling transduction signalling has been clearly investigated (Ju & Chang, 2015). It has been reported that Cd stress modulates ethylene generation in many plant species such as Arabidopsis via the increased expression of 1-aminocyclopropane-1carboxylic acid (ACC) synthase genes (ACS2 and ACS6; Schellingen et al, 2014;Schellingen et al, 2015).…”

Dynamics of Ethylene Production in Response to Compatible Nod Factor

“…Studies in Arabidopsis (Arabidopsis thaliana) have revealed that the ethylene signaling pathway is negatively and redundantly regulated by five receptors: ETHYLENE RESPONSE 1 (ETR1), ETR2, ETHYLENE RESPONSE SENSOR 1 (ERS1), ERS2, and ETHYLENE INSENSITIVE 4 (EIN4; for review, see Ju and Chang, 2015). In the absence of ethylene, these receptors maintain CONSTITUTIVE TRIPLE RESPONSE 1 (CTR1) in an active form to repress EIN2 function.…”