title: Bacterial-induced calcium oscillations are common to nitrogen-fixing associations of nodulating legumes and nonlegumes.
abstract: Plants that form root-nodule symbioses are within a monophyletic 'nitrogen-fixing' clade and associated signalling processes are shared with the arbuscular mycorrhizal symbiosis. Central to symbiotic signalling are nuclear-associated oscillations in calcium ions (Ca(2+) ), occurring in the root hairs of several legume species in response to the rhizobial Nod factor signal. In this study we expanded the species analysed for activation of Ca(2+) oscillations, including nonleguminous species within the nitrogen-fixing clade. We showed that Ca(2+) oscillations are a common feature of legumes in their association with rhizobia, while Cercis, a non-nodulating legume, does not show Ca(2+) oscillations in response to Nod factors from Sinorhizobium fredii NGR234. Parasponia andersonii, a nonlegume that can associate with rhizobia, showed Nod factor-induced calcium oscillations to S. fredii NGR234 Nod factors, but its non-nodulating sister species, Trema tomentosa, did not. Also within the nitrogen-fixing clade are actinorhizal species that associate with Frankia bacteria and we showed that Alnus glutinosa induces Ca(2+) oscillations in root hairs in response to exudates from Frankia alni, but not to S. fredii NGR234 Nod factors. We conclude that the ability to mount Ca(2+) oscillations in response to symbiotic bacteria is a common feature of nodulating species within the nitrogen-fixing clade.
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
authors.forename: Emma
authors.initials: E
authors.lastname: Granqvist
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
authors.forename: Jongho
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Plant Science, Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, the Netherlands.
authors.forename: Rik
authors.initials: R
authors.lastname: Op den Camp
authors.affiliation: Ecologie Microbienne, Centre National de la Recherche Scientifique UMR 5557, Université Lyon I, Université Lyon, Villeurbanne, France.
authors.forename: Petar
authors.initials: P
authors.lastname: Pujic
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
authors.forename: Lionel
authors.initials: L
authors.lastname: Hill
authors.affiliation: Ecologie Microbienne, Centre National de la Recherche Scientifique UMR 5557, Université Lyon I, Université Lyon, Villeurbanne, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Normand
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Morris
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
authors.forename: J Allan
authors.initials: JA
authors.lastname: Downie
authors.affiliation: Department of Plant Science, Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, the Netherlands.
authors.forename: Rene
authors.initials: R
authors.lastname: Geurts
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
authors.forename: Giles E D
authors.initials: GE
authors.lastname: Oldroyd
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism; D020013:Calcium Signaling; D007887:Fabaceae / Q000378:metabolism* / Q000382:microbiology*; D040161:Frankia / Q000502:physiology; D008845:Microinjections; D009586:Nitrogen Fixation; D010802:Phylogeny; D055170:Plant Root Nodulation
chemical_list: D001426:Bacterial Proteins
keywords: Frankia; Parasponia; actinorhizal; calcium oscillations; legumes; nitrogen-fixing clade; nodulation; symbiotic signalling