title: Spontaneous symbiotic reprogramming of plant roots triggered by receptor-like kinases.
abstract: Symbiosis Receptor-like Kinase (SYMRK) is indispensable for the development of phosphate-acquiring arbuscular mycorrhiza (AM) as well as nitrogen-fixing root nodule symbiosis, but the mechanisms that discriminate between the two distinct symbiotic developmental fates have been enigmatic. In this study, we show that upon ectopic expression, the receptor-like kinase genes Nod Factor Receptor 1 (NFR1), NFR5, and SYMRK initiate spontaneous nodule organogenesis and nodulation-related gene expression in the absence of rhizobia. Furthermore, overexpressed NFR1 or NFR5 associated with endogenous SYMRK in roots of the legume Lotus japonicus. Epistasis tests revealed that the dominant active SYMRK allele initiates signalling independently of either the NFR1 or NFR5 gene and upstream of a set of genes required for the generation or decoding of calcium-spiking in both symbioses. Only SYMRK but not NFR overexpression triggered the expression of AM-related genes, indicating that the receptors play a key role in the decision between AM- or root nodule symbiosis-development.
authors.affiliation: Faculty of Biology, Ludwig Maximilians University Munich, Munich, Germany.
authors.forename: Martina Katharina
authors.initials: MK
authors.lastname: Ried
authors.affiliation: Faculty of Biology, Ludwig Maximilians University Munich, Munich, Germany.
authors.forename: Meritxell
authors.initials: M
authors.lastname: Antolín-Llovera
authors.affiliation: Faculty of Biology, Ludwig Maximilians University Munich, Munich, Germany.
authors.forename: Martin
authors.identifier: http://orcid.org/0000-0001-8561-747X
authors.initials: M
authors.lastname: Parniske
mesh_terms: D004843:Epistasis, Genetic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D000070116:Lotus / Q000201:enzymology* / Q000235:genetics / Q000382:microbiology / Q000502:physiology*; D038821:Mycorrhizae / Q000502:physiology; D010770:Phosphotransferases / Q000378:metabolism*; D010940:Plant Proteins; D055170:Plant Root Nodulation / Q000235:genetics; D018517:Plant Roots / Q000201:enzymology* / Q000382:microbiology / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D053204:Root Nodules, Plant / Q000235:genetics / Q000382:microbiology; D015398:Signal Transduction / Q000235:genetics; D013559:Symbiosis / Q000235:genetics
chemical_list: D010940:Plant Proteins; D011956:Receptors, Cell Surface; D010770:Phosphotransferases
keywords: Lotus japonicus; gene regulation; plant biology; plant development; plant root symbiosis; receptor-like kinases; signal transduction