title: RopGEF2 is involved in ABA-suppression of seed germination and post-germination growth of Arabidopsis.
abstract: The involvement of Rho of Plants (ROP) GTPases in abscisic acid (ABA) signalling in Arabidopsis has been demonstrated in many studies. However, the roles of RopGEFs (Rop guanine nucleotide exchange factors), which modulate ROP activities in ABA signalling, are poorly understood. Here, we demonstrate that RopGEF2 may play a negative role in ABA-suppressed seed germination and post-germination growth. We show that disruption of RopGEF2 enhances sensitivity to exogenous ABA in seed germination assays and that RopGEF2pro-GUS is mainly expressed in developing embryos and germinating seeds. Interestingly, YFP-RopGEF2 is located in both the cytoplasmic region and in mitochondria. Notably, the PRONE2 (plant-specific ROP nucleotide exchanger 2) domain of RopGEF2 is detected in mitochondria, whereas the N-terminus of RopGEF2 is shown to be in the cytosol. After ABA treatment, degradation of RopGEF2 is triggered in the cytosol through the ubiquitin-26S proteasome system. The binding of RopGEF2 to ROP2, ROP6 or ROP10, which has been demonstrated to be involved in ABA signalling, not only alters the localization of RopGEF2 but also enables RopGEF2 to escape degradation in the cell. Thus, in this study, we deduce a sophisticated mechanism of ABA-mediated RopGEF2-ROP signalling, which potentially implicates the inactivation of ROPs in responsiveness to ABA.
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
authors.forename: Shujuan
authors.initials: S
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
authors.forename: Yuxuan
authors.initials: Y
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
authors.forename: Yuqing
authors.initials: Y
authors.lastname: He
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
authors.forename: Yarui
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiong
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D003600:Cytosol / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D018525:Germination; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008928:Mitochondria / Q000378:metabolism; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism / Q000502:physiology; D000072417:Protein Domains; D059748:Proteolysis; D012639:Seeds / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D015398:Signal Transduction
chemical_list: D000040:Abscisic Acid; D029681:Arabidopsis Proteins; D019204:GTP-Binding Proteins; D020662:Guanine Nucleotide Exchange Factors; D020559:Monomeric GTP-Binding Proteins; D010937:Plant Growth Regulators; D046988:Proteasome Endopeptidase Complex; C518506:ROP6 protein, Arabidopsis; C000612241:RopGEF2 protein, Arabidopsis; C061553:ATP dependent 26S protease; C472133:ROP10 protein, Arabidopsis; C499714:AT1G20090 protein, Arabidopsis
keywords: Arabidopsis; RopGEF2; abscisic acid; mitochondria; post-germination growth; seed germination; ubiquitin-26S proteasome system