title: Conservation in function of a SCAR/WAVE component during infection thread and root hair growth in Medicago truncatula.
abstract: Nitrogen-fixing symbioses of plants are often associated with bacterially infected nodules where nitrogen fixation occurs. The plant host facilitates bacterial infection with the formation of infection threads, unique structures associated with these symbioses, which are invaginations of the host cell with the capability of traversing cellular junctions. Here, we show that the infection thread shares mechanistic similarities to polar-growing cells, because the required for infection thread (RIT) locus of Medicago truncatula has roles in root-hair, trichome, and infection-thread growth. We show that RIT encodes the M. truncatula ortholog of NAP1, a component of the SCAR/WAVE (suppressor of cAMP receptor/WASP-family verprolin homologous protein) complex that regulates actin polymerization, through the activation of ARP2/3. NAP1 of Arabidopsis thaliana functions equivalently to the M. truncatula gene, indicating that the mode of action of NAP1 is functionally conserved across species and that legumes have not evolved a unique functionality for NAP1 during rhizobial colonization. This work highlights the surprising commonality between polar-growing cells and a polar-growing cellular intrusion and reveals important insights into the formation and maintenance of infection-thread development.
authors: Department of Disease and Stress Biology, John Innes Centre, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, UK.
authors: Akira
authors: A
authors: Miyahara
authors: Jennifer
authors: J
authors: Richens
authors: Colby
authors: C
authors: Starker
authors: Giulia
authors: G
authors: Morieri
authors: Lucinda
authors: L
authors: Smith
authors: Sharon
authors: S
authors: Long
authors: J Allan
authors: JA
authors: Downie
authors: Giles E D
authors: GE
authors: Oldroyd
mesh_terms: D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D046913:Medicago truncatula / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D055170:Plant Root Nodulation / Q000502:physiology*; D018517:Plant Roots / Q000254:growth & development* / Q000502:physiology; D013559:Symbiosis
chemical_list: D010940:Plant Proteins