title: The small GTPase ROP6 interacts with NFR5 and is involved in nodule formation in Lotus japonicus.
abstract: Nod Factor Receptor5 (NFR5) is an atypical receptor-like kinase, having no activation loop in the protein kinase domain. It forms a heterodimer with NFR1 and is required for the early plant responses to Rhizobium infection. A Rho-like small GTPase from Lotus japonicus was identified as an NFR5-interacting protein. The amino acid sequence of this Rho-like GTPase is closest to the Arabidopsis (Arabidopsis thaliana) ROP6 and Medicago truncatula ROP6 and was designated as LjROP6. The interaction between Rop6 and NFR5 occurred both in vitro and in planta. No interaction between Rop6 and NFR1 was observed. Green fluorescent protein-tagged ROP6 was localized at the plasma membrane and cytoplasm. The interaction between ROP6 and NFR5 appeared to take place at the plasma membrane. The expression of the ROP6 gene could be detected in vascular tissues of Lotus roots. After inoculation with Mesorhizobium loti, elevated levels of ROP6 expression were found in the root hairs, root tips, vascular bundles of roots, nodule primordia, and young nodules. In transgenic hairy roots expressing ROP6 RNA interference constructs, Rhizobium entry into the root hairs did not appear to be affected, but infection thread growth through the root cortex were severely inhibited, resulting in the development of fewer nodules per plant. These data demonstrate a role of ROP6 as a positive regulator of infection thread formation and nodulation in L. japonicus.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Danxia
authors.initials: D
authors.lastname: Ke
authors.forename: Qing
authors.initials: Q
authors.lastname: Fang
authors.forename: Chunfen
authors.initials: C
authors.lastname: Chen
authors.forename: Hui
authors.initials: H
authors.lastname: Zhu
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Chang
authors.forename: Songli
authors.initials: S
authors.lastname: Yuan
authors.forename: Heng
authors.initials: H
authors.lastname: Kang
authors.forename: Lian
authors.initials: L
authors.lastname: Ma
authors.forename: Zonglie
authors.initials: Z
authors.lastname: Hong
authors.forename: Zhongming
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D060054:Agrobacterium / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000378:metabolism; D004789:Enzyme Activation; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D000070116:Lotus / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D059128:Mesorhizobium / Q000378:metabolism / Q000472:pathogenicity; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D010788:Photosynthesis; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology; D019441:Plant Epidermis / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D055170:Plant Root Nodulation; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D058526:Plant Vascular Bundle / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D013559:Symbiosis; D014026:Nicotiana / Q000378:metabolism / Q000382:microbiology; D020798:Two-Hybrid System Techniques
chemical_list: D010940:Plant Proteins; D049452:Green Fluorescent Proteins; D020558:GTP Phosphohydrolases; D020559:Monomeric GTP-Binding Proteins