title: Strigolactone-Induced Putative Secreted Protein 1 Is Required for the Establishment of Symbiosis by the Arbuscular Mycorrhizal Fungus Rhizophagus irregularis.
abstract: Arbuscular mycorrhizal (AM) symbiosis is the most widespread association between plants and fungi. To provide novel insights into the molecular mechanisms of AM symbiosis, we screened and investigated genes of the AM fungus Rhizophagus irregularis that contribute to the infection of host plants. R. irregularis genes involved in the infection were explored by RNA-sequencing (RNA-seq) analysis. One of the identified genes was then characterized by a reverse genetic approach using host-induced gene silencing (HIGS), which causes RNA interference in the fungus via the host plant. The RNA-seq analysis revealed that 19 genes are up-regulated by both treatment with strigolactone (SL) (a plant symbiotic signal) and symbiosis. Eleven of the 19 genes were predicted to encode secreted proteins and, of these, SL-induced putative secreted protein 1 (SIS1) showed the largest induction under both conditions. In hairy roots of Medicago truncatula, SIS1 expression is knocked down by HIGS, resulting in significant suppression of colonization and formation of stunted arbuscules. These results suggest that SIS1 is a putative secreted protein that is induced in a wide spatiotemporal range including both the presymbiotic and symbiotic stages and that SIS1 positively regulates colonization of host plants by R. irregularis.
authors.affiliation: 1 Division of Symbiotic Systems, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki 444-8585, Aichi, Japan; and.|2 Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Nishigonaka 38, Myodaiji, Okazaki 444-8585, Aichi, Japan.
authors.forename: Syusaku
authors.initials: S
authors.lastname: Tsuzuki
authors.affiliation: 1 Division of Symbiotic Systems, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki 444-8585, Aichi, Japan; and.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Handa
authors.affiliation: 1 Division of Symbiotic Systems, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki 444-8585, Aichi, Japan; and.|2 Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Nishigonaka 38, Myodaiji, Okazaki 444-8585, Aichi, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Takeda
authors.affiliation: 1 Division of Symbiotic Systems, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki 444-8585, Aichi, Japan; and.|2 Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Nishigonaka 38, Myodaiji, Okazaki 444-8585, Aichi, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kawaguchi
mesh_terms: D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D055785:Gene Knockdown Techniques; D055137:Glomeromycota / Q000235:genetics* / Q000502:physiology; D007783:Lactones / Q000378:metabolism; D046913:Medicago truncatula / Q000382:microbiology*; D038821:Mycorrhizae / Q000235:genetics* / Q000502:physiology; D018517:Plant Roots / Q000382:microbiology; D017423:Sequence Analysis, RNA; D013559:Symbiosis; D059467:Transcriptome
chemical_list: D005656:Fungal Proteins; D007783:Lactones; C483518:strigol