title: Functional analysis of duplicated Symbiosis Receptor Kinase (SymRK) genes during nodulation and mycorrhizal infection in soybean (Glycine max).
abstract: Association between legumes and rhizobia results in the formation of root nodules, where symbiotic nitrogen fixation occurs. The early stages of this association involve a complex of signalling events between the host and microsymbiont. Several genes dealing with early signal transduction have been cloned, and one of them encodes the leucine-rich repeat (LRR) receptor kinase (SymRK; also termed NORK). The Symbiosis Receptor Kinase gene is required by legumes to establish a root endosymbiosis with Rhizobium bacteria as well as mycorrhizal fungi. Using degenerate primer and BAC sequencing, we cloned duplicated SymRK homeologues in soybean called GmSymRKα and GmSymRKβ. These duplicated genes have high similarity of nucleotide (96%) and amino acid sequence (95%). Sequence analysis predicted a malectin-like domain within the extracellular domain of both genes. Several putative cis-acting elements were found in promoter regions of GmSymRKα and GmSymRKβ, suggesting a participation in lateral root development, cell division and peribacteroid membrane formation. The mutant of SymRK genes is not available in soybean; therefore, to know the functions of these genes, RNA interference (RNAi) of these duplicated genes was performed. For this purpose, RNAi construct of each gene was generated and introduced into the soybean genome by Agrobacterium rhizogenes-mediated hairy root transformation. RNAi of GmSymRKβ gene resulted in an increased reduction of nodulation and mycorrhizal infection than RNAi of GmSymRKα, suggesting it has the major activity of the duplicated gene pair. The results from the important crop legume soybean confirm the joint phenotypic action of GmSymRK genes in both mycorrhizal and rhizobial infection seen in model legumes.
authors.affiliation: Centre for Integrative Legume Research, School of Agriculture and Food Sciences, The University of Queensland, St Lucia, Brisbane 4072, QLD, Australia.
authors.forename: Arief
authors.initials: A
authors.lastname: Indrasumunar
authors.affiliation: Centre for Integrative Legume Research, School of Agriculture and Food Sciences, The University of Queensland, St Lucia, Brisbane 4072, QLD, Australia.
authors.forename: Julia
authors.initials: J
authors.lastname: Wilde
authors.affiliation: Centre for Integrative Legume Research, School of Agriculture and Food Sciences, The University of Queensland, St Lucia, Brisbane 4072, QLD, Australia.
authors.forename: Satomi
authors.initials: S
authors.lastname: Hayashi
authors.affiliation: Centre for Integrative Legume Research, School of Agriculture and Food Sciences, The University of Queensland, St Lucia, Brisbane 4072, QLD, Australia.
authors.forename: Dongxue
authors.initials: D
authors.lastname: Li
authors.affiliation: Centre for Integrative Legume Research, School of Agriculture and Food Sciences, The University of Queensland, St Lucia, Brisbane 4072, QLD, Australia. Electronic address: p.gresshoff@uq.edu.au.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Gresshoff
mesh_terms: D000595:Amino Acid Sequence; D022202:Chromosomes, Artificial, Bacterial; D002999:Clone Cells; D018506:Gene Expression Regulation, Plant; D020131:Genes, Duplicate; D017343:Genes, Plant; D008969:Molecular Sequence Data; D038821:Mycorrhizae / Q000502:physiology*; D059372:Nucleotide Motifs / Q000235:genetics; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D055170:Plant Root Nodulation / Q000235:genetics*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D020794:Receptor Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013025:Glycine max / Q000201:enzymology / Q000235:genetics* / Q000382:microbiology*; D013559:Symbiosis / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D010940:Plant Proteins; D021382:Protein Sorting Signals; D020794:Receptor Protein-Tyrosine Kinases
keywords: Gene duplication; Glycine max; Symbiosis; Symbiosis receptor kinase