title: Lotus japonicus ARPC1 is required for rhizobial infection.
abstract: Remodeling of the plant cell cytoskeleton precedes symbiotic entry of nitrogen-fixing bacteria within the host plant roots. Here we identify a Lotus japonicus gene encoding a predicted ACTIN-RELATED PROTEIN COMPONENT1 (ARPC1) as essential for rhizobial infection but not for arbuscular mycorrhiza symbiosis. In other organisms ARPC1 constitutes a subunit of the ARP2/3 complex, the major nucleator of Y-branched actin filaments. The L. japonicus arpc1 mutant showed a distorted trichome phenotype and was defective in epidermal infection thread formation, producing mostly empty nodules. A few partially colonized nodules that did form in arpc1 contained abnormal infections. Together with previously described L. japonicus Nck-associated protein1 and 121F-specific p53 inducible RNA mutants, which are also impaired in the accommodation of rhizobia, our data indicate that ARPC1 and, by inference a suppressor of cAMP receptor/WASP-family verpolin homologous protein-ARP2/3 pathway, must have been coopted during evolution of nitrogen-fixing symbiosis to specifically mediate bacterial entry.
authors.affiliation: Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, London, Ontario, Canada N5V 4T3.
authors.forename: Md Shakhawat
authors.initials: MS
authors.lastname: Hossain
authors.forename: Jinqiu
authors.initials: J
authors.lastname: Liao
authors.forename: Euan K
authors.initials: EK
authors.lastname: James
authors.forename: Shusei
authors.initials: S
authors.lastname: Sato
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tabata
authors.forename: Anna
authors.initials: A
authors.lastname: Jurkiewicz
authors.forename: Lene H
authors.initials: LH
authors.lastname: Madsen
authors.forename: Jens
authors.initials: J
authors.lastname: Stougaard
authors.forename: Loretta
authors.initials: L
authors.lastname: Ross
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Szczyglowski
mesh_terms: D008841:Actin Cytoskeleton / Q000235:genetics / Q000378:metabolism; D051376:Actin-Related Protein 2-3 Complex / Q000235:genetics / Q000378:metabolism; D016960:Agrobacterium tumefaciens / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005816:Genetic Complementation Test; D056426:Genetic Loci; D000070116:Lotus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000382:microbiology; D059128:Mesorhizobium / Q000254:growth & development*; D009154:Mutation; D038821:Mycorrhizae / Q000254:growth & development; D010641:Phenotype; D019441:Plant Epidermis / Q000378:metabolism / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D053204:Root Nodules, Plant / Q000254:growth & development* / Q000382:microbiology; D012639:Seeds / Q000235:genetics / Q000378:metabolism; D013559:Symbiosis
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D010940:Plant Proteins; D012333:RNA, Messenger