title: CPK3-phosphorylated RhoGDI1 is essential in the development of Arabidopsis seedlings and leaf epidermal cells.
abstract: The regulation of Rho of plants (ROP) in morphogenesis of leaf epidermal cells has been well studied, but the roles concerning regulators of ROPs such as RhoGDIs are poorly understood. This study reports that AtRhoGDI1 (GDI1) acts as a versatile regulator to modulate development of seedlings and leaf pavement cells. In mutant gdi1, leaf pavement cells showed shorter lobes in comparison with those in wild type. In GDI1-14 seedlings (GDI1-overexpression line) the growth of lobes in pavement cells was severely suppressed and the development of seedlings was altered. These results indicate that GDI1 plays an essential role in morphogenesis of epidermal pavement cells through modulating the ROP signalling pathways. The interaction between GDI1 and ROP2 or ROP6 was detected in the leaf pavement cells using FRET analysis. Dominant negative, not constitutively active, DN-rop6 could weaken the effect caused by overexpression of GDI1; because the pleiotropic phenotype of GDI1-14 plants was eliminated in the hybrid line GDI1-14 DN-rop6. GDI1 could be phosphorylated by CPK3. Three conserved Ser/Thr residues in GDI1 were determined as targeted amino acids for CPK3. Overexpression of GDI1(3D), not GDI1(3A), could rescue the abnormal growth phenotypes of gdi1-1 seedlings, demonstrating the impact of GDI1 phosphorylation in the development of Arabidopsis. In summary, these results suggest that GDI1 regulation in morphogenesis of seedlings and leaf pavement cells could be undergone through modulating the ROP signalling pathways and the phosphorylation of GDI1 by CPK3 was required for the developmental modulation in Arabidopsis.
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.forename: Shujuan
authors.initials: S
authors.lastname: Zhao
authors.forename: Han
authors.initials: H
authors.lastname: Tian
authors.forename: Yuqing
authors.initials: Y
authors.lastname: He
authors.forename: Wei
authors.initials: W
authors.lastname: Xiong
authors.forename: Lin
authors.initials: L
authors.lastname: Guo
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D010766:Phosphorylation; D019441:Plant Epidermis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D062948:rho Guanine Nucleotide Dissociation Inhibitor alpha / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D062948:rho Guanine Nucleotide Dissociation Inhibitor alpha; C516786:CPK3 protein, Arabidopsis; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002118:Calcium
keywords: CPK3; Calcium; GDI1; ROP.; pavement cells; phosphorylation