Molecular association of Arabidopsis RTH with its homolog RTE1 in regulating ethylene signaling

Abstract

The plant hormone ethylene affects many biological processes during plant growth and development. Ethylene is perceived by ethylene receptors at the endoplasmic reticulum (ER) membrane. The ETR1 ethylene receptor is positively regulated by the transmembrane protein RTE1, which localizes to the ER and Golgi apparatus. The RTE1 gene family is conserved in animals, plants, and lower eukaryotes. In Arabidopsis, RTE1-HOMOLOG (RTH) is the only homolog of the Arabidopsis RTE1 gene family. The regulatory function of the Arabidopsis RTH in ethylene signaling and plant growth is largely unknown. The present study shows Arabidopsis RTH gene expression patterns, protein co-localization with the ER and Golgi apparatus, and the altered ethylene response phenotype when RTH is knocked out or overexpressed in Arabidopsis. Compared with rte1 mutants, rth mutants exhibit less sensitivity to exogenous ethylene, while RTH overexpression confers ethylene hypersensitivity. Genetic analyses indicate that Arabidopsis RTH might not directly regulate the ethylene receptors. RTH can physically interact with RTE1, and evidence supports that RTH might act via RTE1 in regulating ethylene responses and signaling. The present study advances our understanding of the regulatory function of the Arabidopsis RTE1 gene family members in ethylene signaling.

The regulatory module MdPUB29‐MdbHLH3 connects ethylene biosynthesis with fruit quality in apple

“…In addition to the ethylene biosynthetic pathway, the ethylene signaling pathway has also been extensively studied for decades, and novel components are being unceasingly uncovered (Merchante et al, 2013;Zheng & Zhu, 2016;Zheng et al, 2017). The linear ethylene signal transduction pathway starts with the perception of ethylene by its receptors (Chang et al, 1993), and the signal is delivered downstream through several components, including CONSTITUTIVE TRIPLE RESPONSE1 (CTR1) and ETHYLENE INSENSITIVE2 (EIN2; Kieber et al, 1993;Alonso et al, 1999).…”

Amplification and Adaptation in the Ethylene Signaling Pathway

“…[135] Phylogenetic and functional analyses indicate that plants contain families of proteins related to RTE1/GR, although these appear to have variable roles in regulation of the ethylene response (Figure 6B). [135,138,139,143,144] The Arabidopsis genome also encodes RTE1-HOMOLOG (RTH), which like RTE1 localizes to the ER and the Golgi apparatus. [143] However, RTH loss-offunction and overexpression phenotypes are the opposite of what are found with RTE1; RTH LOF mutants exhibit slightly reduced ethylene sensitivity and GOF mutants slightly increased ethylene sensitivity (i.e.…”

“…[135,138,139,143,144] The Arabidopsis genome also encodes RTE1-HOMOLOG (RTH), which like RTE1 localizes to the ER and the Golgi apparatus. [143] However, RTH loss-offunction and overexpression phenotypes are the opposite of what are found with RTE1; RTH LOF mutants exhibit slightly reduced ethylene sensitivity and GOF mutants slightly increased ethylene sensitivity (i.e. RTH appears to be a positive regulator of ethylene responses).…”

“…[143] The effect on ethylene sensitivity may be indirect due to a physical association with RTE1. [143] Unlike RTE1, RTH is not a direct target for EIN3 based on ChIP-Seq analysis, [113] consistent with it not being involved in the primary response to ethylene (Figure 6C). The tomato genome encodes two homologues to GR, Green Ripe Like1 (GRL1) and Green Ripe Like2 (GRL2).…”

Arabidopsis CPR5 plays a role in regulating nucleocytoplasmic transport of mRNAs in ethylene signaling pathway

“…Among the ve ethylene receptors in Arabidopsis, ETR1 was believed to play a predominant role in ethylene signaling (Hua et al, 1995;Hall and Bleecker, 2003;Qu et al, 2007;Liu et al, 2010). To explore the regulation mechanism of the ETR1 receptor, we and colleagues previously reported the isolation of the ETR1 receptor-associated protein RTE1 and CPR5 based on their regulatory functions in the ETR1 receptor signaling (Resnick et al, 2006;Zhou et al, 2007;Dong et al, 2008;Dong et al, 2010;Wang et al, 2017;Zheng et al, 2017).…”