Inter‐relationships between the heterotrimeric Gβ subunit AGB1, the receptor‐like kinase FERONIA, and RALF1 in salinity response

Abstract

Plant heterotrimeric G proteins modulate numerous developmental stress responses. Recently, receptor-like kinases (RLKs) have been implicated as functioning with G proteins and may serve as plant G-protein-coupled-receptors. The RLK FERONIA (FER), in the Catharantus roseus RLK1-like subfamily, is activated by a family of polypeptides called rapid alkalinization factors (RALFs). We previously showed that the Arabidopsis G protein β subunit, AGB1, physically interacts with FER, and that RALF1 regulation of stomatal movement through FER requires AGB1. Here, we investigated genetic interactions of AGB1 and FER in plant salinity response by comparing salt responses in the single and double mutants of agb1 and fer. We show that AGB1 and FER act additively or synergistically depending on the conditions of the NaCl treatments. We further show that the synergism likely occurs through salt-induced ROS production. In addition, we show that RALF1 enhances salt toxicity through increasing Na accumulation and decreasing K accumulation rather than by inducing ROS production, and that the RALF1 effect on salt response occurs in an AGB1-independent manner. Our results indicate that RLK epistatic relationships are not fixed, as AGB1 and FER display different genetic relationships to RALF1 in stomatal versus salinity responses.

The Role of Gβ Protein in Controlling Cell Expansion via Potential Interaction with Lipid Metabolic Pathways

“…The most elaborate data are available from Arabidopsis where G-protein mutants exhibit altered phenotypes in response to almost all plant hormones at the physiological and molecular (large-scale omics) level (Pandey and Assmann, 2004;Pandey et al, 2006Pandey et al, , 2008Pandey et al, , 2009Pandey et al, , 2010Fan et al, 2008;Zhao et al, 2010;Alvarez et al, 2011;Chakravorty et al, 2011;Jin et al, 2013;Tsugama et al, 2013;Wang et al, 2017;Peng et al, 2018;Zhang et al, 2018b). Similarly, G-protein mutants in Arabidopsis (and other plants) show altered sensitivity to multiple abiotic stresses such as drought, temperature, salt, redox, ultraviolet, and high light (Zhang et al, 2011;He et al, 2013;Torres et al, 2013;Subramaniam et al, 2016;Lee et al, 2017;Kaur et al, 2018;Yu and Assmann, 2018). G-proteins also mediate regulation of defense responses against host and nonhost bacterial pathogens, a variety of biotrophic and necrotrophic fungi and viruses (Liu et al, 2013;Lorek et al, 2013;Aranda-Sicilia et al, 2015;Cheng et al, 2015;Maruta et al, 2015;Meng et al, 2015;Liang et al, 2016Liang et al, , 2018Yuan et al, 2017;Bi et al, 2018;Wang et al, 2018).…”

FERONIA regulates auxin‐mediated lateral root development and primary root gravitropism

“…Apart from affecting auxin and ABA responses, FER was shown to inhibit ethylene synthesis and signaling and to control ethylene and BR-regulated hypocotyl elongation [8,10]. Additional functions of FER include cell growth, sensing and maintaining cell wall integrity, and salt stress tolerance [14][15][16][17][18]. Additional functions of FER include cell growth, sensing and maintaining cell wall integrity, and salt stress tolerance [14][15][16][17][18].…”

“…Recent studies of the Rapid Alkalinization Factor-FER pathway indicate that FER may modulate immune signaling [11][12][13]. Additional functions of FER include cell growth, sensing and maintaining cell wall integrity, and salt stress tolerance [14][15][16][17][18].…”

FERONIA cytoplasmic domain: node of varied signal outputs

“…Currently, 14 of the 17 CrRLK1Ls in Arabidopsis thaliana and 5 of the 17 CrRLK1Ls in Oryza sativa have been investigated using genetic techniques (Table 1). Shih et al 2014;Li et al 2015;Kessler et al 2010;Haruta et al 2014;Hansen et al 2018;Ngo et al 2014;Huck et al 2003;Escobar-Restrepo et al 2007;Stegmann et al 2017;Keinath et al 2010;Deslauriers and Larsen 2010;Yang et al 2015;Huang et al 2013;Chen et al 2016;Mao et al 2015;Duan et al 2010;Yu 2014;Feng et al 2018;Yu and Assmann 2018;Xu 2019;Zhu et al 2020;Zhao et al 2018;Kessler et al 2015;Haruta et al 2018;Chakravorty et al 2018;Du 2016;Hansen et al 2019;Dunser et al 2019;Dong et al 2019;Yu et al 2018;Yin et al 2018 have recently been identified as one of the ligands of CrRLK1L family (Haruta et al 2014;Gonneau et al 2018;Ge et al 2017;Stegmann et al 2017). RALFs belongs to a group of cysteine-rich small peptides found in various plant species, and participate in pathogen response, plant growth regulation, and PT generation and growth (Haruta et al 2014;Gonneau et al 2018;Ge et al 2017;Stegmann et al 2017;…”

“…Studies on the roles that FER play in these processes suggest that FER has functional diversity, complexity, and that its activity may depend on the cell type and/or the growth environment. FER regulates cell sizes and modulates cell shape Duan et al 2010;Yu et al 2014;), regulates flowering time (Wang et al 2020a), regulates biotic responses during stress and defense response Masachis et al 2016;Guo et al 2018), as well as mediating the abiotic response during root mechanical (Shih et al 2014) and salinity stresses (Chen et al 2016;Feng et al 2018;Yu and Assmann 2018). Besides these functions, FER modulates cellulose and starch content, carbon/nitrogen (C/N) responses Yeats et al 2016;Xu et al 2019) and cell-wall integrity (Feng et al 2018).…”