title: Negative regulation of CCaMK is essential for symbiotic infection.
abstract: One of the earliest responses of legumes to symbiotic signalling is oscillation of the calcium concentration in the nucleoplasm of root epidermal cells. Integration and decoding of the calcium-spiking signal involve a calcium- and calmodulin-dependent protein kinase (CCaMK) and its phosphorylation substrates, such as CYCLOPS. Here we describe the Lotus japonicus ccamk-14 mutant that originated from a har1-1 suppressor screen. The ccamk-14 mutation causes a serine to asparagine substitution at position 337 located within the calmodulin binding site, which we determined to be an in vitro phosphorylation site in CCaMK. We show that ccamk-14 exerts cell-specific effects on symbiosis. The mutant is characterized by an increased frequency of epidermal infections and significantly compromised cortical infections by Mesorhizobium loti and also the arbuscular mycorrhiza fungus Rhizophagus irregularis. The S337 residue is conserved across angiosperm CCaMKs, and testing discrete substitutions at this site showed that it participates in a negative regulation of CCaMK activity, which is required for the cell-type-specific integration of symbiotic signalling.
authors: Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, London, Ontario N5V 4T3, Canada.
authors: Jinqiu
authors: J
authors: Liao
authors: Sylvia
authors: S
authors: Singh
authors: Md S
authors: MS
authors: Hossain
authors: Stig U
authors: SU
authors: Andersen
authors: Loretta
authors: L
authors: Ross
authors: Dario
authors: D
authors: Bonetta
authors: Yonghong
authors: Y
authors: Zhou
authors: Shusei
authors: S
authors: Sato
authors: Satoshi
authors: S
authors: Tabata
authors: Jens
authors: J
authors: Stougaard
authors: Krzysztof
authors: K
authors: Szczyglowski
authors: Martin
authors: M
authors: Parniske
mesh_terms: D000483:Alleles; D019943:Amino Acid Substitution; D001216:Asparagine / Q000378:metabolism; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase / Q000235:genetics / Q000378:metabolism*; D002874:Chromosome Mapping; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D000070116:Lotus / Q000201:enzymology* / Q000235:genetics / Q000382:microbiology; D059128:Mesorhizobium / Q000254:growth & development; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D038821:Mycorrhizae / Q000254:growth & development; D010641:Phenotype; D010766:Phosphorylation; D019441:Plant Epidermis / Q000378:metabolism / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D012694:Serine / Q000378:metabolism; D013559:Symbiosis
chemical_list: D012694:Serine; D001216:Asparagine; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; D002118:Calcium