title: The μ Subunit of Arabidopsis Adaptor Protein-2 Is Involved in Effector-Triggered Immunity Mediated by Membrane-Localized Resistance Proteins.
abstract: Endocytosis has been suggested to be important in the cellular processes of plant immune responses. However, our understanding of its role during effector-triggered immunity (ETI) is still limited. We have previously shown that plant endocytosis, especially clathrin-coated vesicle formation at the plasma membrane, is mediated by the adaptor protein-2 (AP-2) complex and that loss of the μ subunit of AP-2 (AP2M) affects plant growth and floral organ development. Here, we report that AP2M is required for full-strength ETI mediated by the disease resistance (R) genes RPM1 and RPS2 in Arabidopsis. Reduced ETI was observed in an ap2m mutant plant, measured by growth of Pseudomonas syringae pv. tomato DC3000 strains carrying the corresponding effector genes avrRpm1 or avrRpt2 and by hypersensitive cell death response and defense gene expression triggered by these strains. In contrast, RPS4-mediated ETI and its associated immune responses were not affected by the ap2m mutation. While RPM1 and RPS2 are localized to the plasma membrane, RPS4 is localized to the cytoplasm and nucleus. Our results suggest that AP2M is involved in ETI mediated by plasma membrane-localized R proteins, possibly by mediating endocytosis of the immune receptor complex components from the plasma membrane.
authors.affiliation: 1 Department of Plant Biology, Microbial and Plant Genomics Institute, University of Minnesota, 1500 Gortner Ave., St. Paul, MN 55108, U.S.A.; and.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Hatsugai
authors.affiliation: 1 Department of Plant Biology, Microbial and Plant Genomics Institute, University of Minnesota, 1500 Gortner Ave., St. Paul, MN 55108, U.S.A.; and.
authors.forename: Rachel
authors.initials: R
authors.lastname: Hillmer
authors.affiliation: 2 Department of Botany, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Yamaoka
authors.affiliation: 2 Department of Botany, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Ikuko
authors.initials: I
authors.lastname: Hara-Nishimura
authors.affiliation: 1 Department of Plant Biology, Microbial and Plant Genomics Institute, University of Minnesota, 1500 Gortner Ave., St. Paul, MN 55108, U.S.A.; and.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Katagiri
mesh_terms: D033962:Adaptor Protein Complex 2 / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death; D002462:Cell Membrane / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D009154:Mutation; D018515:Plant Leaves; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D021122:Protein Subunits; D021381:Protein Transport / Q000502:physiology*; D017382:Reactive Oxygen Species
chemical_list: D033962:Adaptor Protein Complex 2; D029681:Arabidopsis Proteins; D010940:Plant Proteins; D021122:Protein Subunits; C095014:RPM1 protein, Arabidopsis; C405209:RPT2 protein, Arabidopsis; D017382:Reactive Oxygen Species; C097421:rps4 protein, plant