title: Heterotrimeric G-proteins in Picea abies and their regulation in response to Heterobasidion annosum s.l. infection.
abstract: BACKGROUND
  Heterotrimeric G-proteins are important signalling switches, present in all eukaryotic kingdoms. In plants they regulate several developmental functions and play an important role in plant-microbe interactions. The current knowledge on plant G-proteins is mostly based on model angiosperms and little is known about the G-protein repertoire and function in other lineages. In this study we investigate the heterotrimeric G-protein subunit repertoire in Pinaceae, including phylogenetic relationships, radiation and sequence diversity levels in relation to other plant linages. We also investigate functional diversification of the G-protein complex in Picea abies by analysing transcriptional regulation of the G-protein subunits in different tissues and in response to pathogen infection.
  
  
  RESULTS
  A full repertoire of G-protein subunits in several conifer species were identified in silico. The full-length P. abies coding regions of one Gα-, one Gβ- and four Gγ-subunits were cloned and sequenced. The phylogenetic analysis of the Gγ-subunits showed that PaGG1 clustered with A-type-like subunits, PaGG3 and PaGG4 clustered with C-type-like subunits, while PaGG2 and its orthologs represented a novel conifer-specific putative Gγ-subunit type. Gene expression analyses by quantitative PCR of P. abies G-protein subunits showed specific up-regulation of the Gα-subunit gene PaGPA1 and the Gγ-subunit gene PaGG1 in response to Heterobasidion annosum sensu lato infection.
  
  
  CONCLUSIONS
  Conifers possess a full repertoire of G-protein subunits. The differential regulation of PaGPA1 and PaGG1 indicates that the heterotrimeric G-protein complex represents a critical linchpin in Heterobasidion annosum s.l. perception and downstream signaling in P. abies.
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden. Sophie.Rommel@hhu.de.|Institute of Population Genetics, Heinrich Heine-University, Düsseldorf, Germany. Sophie.Rommel@hhu.de.
authors.forename: Sophie
authors.initials: S
authors.lastname: de Vries
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden. Miguel.Nemesiogorriz@slu.se.
authors.forename: Miguel
authors.initials: M
authors.lastname: Nemesio-Gorriz
authors.affiliation: Department of Biology, The University of Alabama at Birmingham, Birmingham, AL, USA. pbblair@uab.edu.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Blair
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden. Magnus.Karlsson@slu.se.
authors.forename: Magnus
authors.initials: M
authors.lastname: Karlsson
authors.affiliation: Department of Biology, The University of Alabama at Birmingham, Birmingham, AL, USA. smukhtar@uab.edu.
authors.forename: M Shahid
authors.initials: MS
authors.lastname: Mukhtar
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden. Malin.Elfstrand@slu.se.
authors.forename: Malin
authors.initials: M
authors.lastname: Elfstrand
mesh_terms: D000595:Amino Acid Sequence; D001487:Basidiomycota / Q000502:physiology*; D019281:Dimerization; D018506:Gene Expression Regulation, Plant; D020962:Heterotrimeric GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D028222:Picea / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D010940:Plant Proteins; D021122:Protein Subunits; D020962:Heterotrimeric GTP-Binding Proteins