title: Type B Heterotrimeric G Protein γ-Subunit Regulates Auxin and ABA Signaling in Tomato.
abstract: Heterotrimeric G proteins composed of α, β, and γ subunits are central signal transducers mediating the cellular response to multiple stimuli in most eukaryotes. Gγ subunits provide proper cellular localization and functional specificity to the heterotrimer complex. Plant Gγ subunits, divided into three structurally distinct types, are more diverse than their animal counterparts. Type B Gγ subunits, lacking a carboxyl-terminal isoprenylation motif, are found only in flowering plants. We present the functional characterization of type B Gγ subunit (SlGGB1) in tomato (Solanum lycopersicum). We show that SlGGB1 is the most abundant Gγ subunit in tomato and strongly interacts with the Gβ subunit. Importantly, the green fluorescent protein-SlGGB1 fusion protein as well as the carboxyl-terminal yellow fluorescent protein-SlGGB1/amino-terminal yellow fluorescent protein-Gβ heterodimer were localized in the plasma membrane, nucleus, and cytoplasm. RNA interference-mediated silencing of SlGGB1 resulted in smaller seeds, higher number of lateral roots, and pointy fruits. The silenced lines were hypersensitive to exogenous auxin, while levels of endogenous auxins were lower or similar to those of the wild type. SlGGB1-silenced plants also showed strong hyposensitivity to abscisic acid (ABA) during seed germination but not in other related assays. Transcriptome analysis of the transgenic seeds revealed abnormal expression of genes involved in ABA sensing, signaling, and response. We conclude that the type B Gγ subunit SlGGB1 mediates auxin and ABA signaling in tomato.
authors.affiliation: Plant Genetic Engineering Laboratory (G.S., Y.T., J.R.B.) and Centre for Integrative Legume Research (S.H., J.B.), School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland 4072, Australia; andInstituto de Horticultura Subtropical y Mediterranea La Mayora, Consejo Superior de Investigaciones Científicas, Universidad de Malaga, Experimental Station La Mayora, 29750 Algarrobo-Costa, Malaga, Spain (C.L.-E.).
authors.forename: Gayathery
authors.initials: G
authors.lastname: Subramaniam
authors.affiliation: Plant Genetic Engineering Laboratory (G.S., Y.T., J.R.B.) and Centre for Integrative Legume Research (S.H., J.B.), School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland 4072, Australia; andInstituto de Horticultura Subtropical y Mediterranea La Mayora, Consejo Superior de Investigaciones Científicas, Universidad de Malaga, Experimental Station La Mayora, 29750 Algarrobo-Costa, Malaga, Spain (C.L.-E.).
authors.forename: Yuri
authors.initials: Y
authors.lastname: Trusov
authors.affiliation: Plant Genetic Engineering Laboratory (G.S., Y.T., J.R.B.) and Centre for Integrative Legume Research (S.H., J.B.), School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland 4072, Australia; andInstituto de Horticultura Subtropical y Mediterranea La Mayora, Consejo Superior de Investigaciones Científicas, Universidad de Malaga, Experimental Station La Mayora, 29750 Algarrobo-Costa, Malaga, Spain (C.L.-E.).
authors.forename: Carlos
authors.identifier: http://orcid.org/0000-0001-5002-5626
authors.initials: C
authors.lastname: Lopez-Encina
authors.affiliation: Plant Genetic Engineering Laboratory (G.S., Y.T., J.R.B.) and Centre for Integrative Legume Research (S.H., J.B.), School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland 4072, Australia; andInstituto de Horticultura Subtropical y Mediterranea La Mayora, Consejo Superior de Investigaciones Científicas, Universidad de Malaga, Experimental Station La Mayora, 29750 Algarrobo-Costa, Malaga, Spain (C.L.-E.).
authors.forename: Satomi
authors.initials: S
authors.lastname: Hayashi
authors.affiliation: Plant Genetic Engineering Laboratory (G.S., Y.T., J.R.B.) and Centre for Integrative Legume Research (S.H., J.B.), School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland 4072, Australia; andInstituto de Horticultura Subtropical y Mediterranea La Mayora, Consejo Superior de Investigaciones Científicas, Universidad de Malaga, Experimental Station La Mayora, 29750 Algarrobo-Costa, Malaga, Spain (C.L.-E.).
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Batley
authors.affiliation: Plant Genetic Engineering Laboratory (G.S., Y.T., J.R.B.) and Centre for Integrative Legume Research (S.H., J.B.), School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland 4072, Australia; andInstituto de Horticultura Subtropical y Mediterranea La Mayora, Consejo Superior de Investigaciones Científicas, Universidad de Malaga, Experimental Station La Mayora, 29750 Algarrobo-Costa, Malaga, Spain (C.L.-E.) j.botella@uq.edu.au.
authors.forename: José Ramón
authors.identifier: http://orcid.org/0000-0002-4446-3432
authors.initials: JR
authors.lastname: Botella
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism / Q000494:pharmacology*; D053898:Biosynthetic Pathways / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D005638:Fruit / Q000033:anatomy & histology / Q000187:drug effects; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D020868:Gene Silencing / Q000187:drug effects; D017343:Genes, Plant; D018525:Germination / Q000187:drug effects; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism* / Q000494:pharmacology; D018551:Solanum lycopersicum / Q000187:drug effects / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D030821:Plants, Genetically Modified; D011485:Protein Binding / Q000187:drug effects / Q000235:genetics; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism*; D012639:Seeds / Q000033:anatomy & histology / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D007210:Indoleacetic Acids; D010940:Plant Proteins; D021122:Protein Subunits; D000040:Abscisic Acid; D020962:Heterotrimeric GTP-Binding Proteins