Ethylene Signaling in Rice and Arabidopsis: Conserved and Diverged Aspects  Chao Yang, Xiang Lu, Biao Ma, Shou-Yi Chen, Jin-Song Zhang  Molecular Plant  Volume 8, Issue 4, Pages 495-505 (April 2015) DOI: 10.1016/j.molp.2015.01.003 Copyright © 2015 The Author Terms and Conditions

Figure 1 The Model of Ethylene Signaling Pathway in Arabidopsis. Ethylene is perceived in the ER by a family of receptors that show similarity to two-component histidine kinase sensors from bacteria (Chang et al., 1993; Hua et al., 1995, 1998; Sakai et al., 1998). In air, the ethylene level is low. The active receptors interact with the N-terminal region of CTR1 to form a complex (Kieber et al., 1993; Gao et al., 2003; Huang et al., 2003). CTR1 directly phosphorylates the C-terminal domain of EIN2 and then leads to the degradation of EIN2 by F-box proteins EPT1/2 to repress the downstream signaling transduction (Alonso et al., 1999; Qiao et al., 2009; Ju et al., 2012). In the nucleus, EIN3/EIL1 are degraded through ubiquitin-proteasome mediated by F-box proteins EBF1/2 (Chao et al., 1997; Guo and Ecker, 2003; Potuschak et al., 2003; Gagne et al., 2004; An et al., 2010). In the presence of ethylene, ethylene binding leads to the inactivation of ethylene receptors and CTR1, which then results in the dephosphorylation of EIN2 and thus its cleavage. The split EIN2 C-terminal fragment (CEND) transports into the nucleus and participates in the stabilization and accumulation of EIN3/EIL1 and, consequently, induces transcription of ERF1 and other ethylene-responsive genes (Solano et al., 1998; Ju et al., 2012; Qiao et al., 2012; Wen et al., 2012). Molecular Plant 2015 8, 495-505DOI: (10.1016/j.molp.2015.01.003) Copyright © 2015 The Author Terms and Conditions

Figure 2 Comparison of the Ethylene Response Phenotypes in Dark-Grown Seedlings of (A) Arabidopsis, (B) Rice, (C) Brachypodium distachyon, (D) Maize, (E) Wheat, and (F) Sorghum. Arabidopsis seedlings (Col-0) were grown on the half-strength MS medium and incubated at 23°C in the dark for 3 d in the presence and absence of ethylene. Germinated rice (cv. Nipponbare) seeds were placed on a stainless net with the water level below the seeds at 28°C in the dark for 3 d with or without ethylene treatment (described in Ma et al., 2013). Brachypodium distachyon (Brachypodium distachyon 21), maize (Zea mays L. inbred B73), wheat (Jing 411), and sorghum (Sorghum bicolor M81-E) were treated similarly with ethylene and grown for 2 d. The ethylene concentration was 10 ppm. Bars, 1 cm. Molecular Plant 2015 8, 495-505DOI: (10.1016/j.molp.2015.01.003) Copyright © 2015 The Author Terms and Conditions