title: SPL28 encodes a clathrin-associated adaptor protein complex 1, medium subunit micro 1 (AP1M1) and is responsible for spotted leaf and early senescence in rice (Oryza sativa).
abstract: To expand our understanding of cell death in plant defense responses, we isolated a novel rice (Oryza sativa) spotted leaf mutant (spl28) that displays a lesion mimic phenotype in the absence of pathogen attack through treatment of Hwacheongbyeo (an elite Korean japonica cultivar) with N-methyl-N-nitrosourea (MNU). Early stage development of the spl28 mutant was normal. However, after flowering, spl28 mutants exhibited a significant decrease in chlorophyll content, soluble protein content, and photosystem II efficiency, and high concentrations of reactive oxygen species (ROS), phytoalexin, callose, and autofluorescent phenolic compounds that localized in or around the lesions. The spl28 mutant also exhibited significantly enhanced resistance to rice blast and bacterial blight. Using a map-based cloning approach, we determined that SPL28 encodes a clathrin-associated adaptor protein complex 1, medium subunit micro 1 (AP1M1), which is involved in the post-Golgi trafficking pathway. A green fluorescent protein (GFP) fusion protein of SPL28 (SPL28::GFP) localized to the Golgi apparatus, and expression of SPL28 complemented the membrane trafficking defect of apm1-1 Delta yeast mutants. SPL28 was ubiquitously expressed and contained a highly conserved adaptor complex medium subunit (ACMS) family domain. SPL28 appears to be involved in the regulation of vesicular trafficking, and SPL28 dysfunction causes the formation of hypersensitive response (HR)-like lesions, leading to the initiation of leaf senescence.
authors.affiliation: Department of Plant Science, Research Institute for Agriculture and Life Sciences, and Plant Genomics and Breeding Institute, Seoul National University, Seoul, 151-921, Republic of Korea.
authors.forename: Yongli
authors.initials: Y
authors.lastname: Qiao
authors.forename: Wenzhu
authors.initials: W
authors.lastname: Jiang
authors.forename: JooHyun
authors.initials: J
authors.lastname: Lee
authors.forename: BongSoo
authors.initials: B
authors.lastname: Park
authors.forename: Min-Seon
authors.initials: MS
authors.lastname: Choi
authors.forename: Rihua
authors.initials: R
authors.lastname: Piao
authors.forename: Mi-Ok
authors.initials: MO
authors.lastname: Woo
authors.forename: Jae-Hwan
authors.initials: JH
authors.lastname: Roh
authors.forename: Longzhi
authors.initials: L
authors.lastname: Han
authors.forename: Nam-Chon
authors.initials: NC
authors.lastname: Paek
authors.forename: Hak Soo
authors.initials: HS
authors.lastname: Seo
authors.forename: Hee-Jong
authors.initials: HJ
authors.lastname: Koh
mesh_terms: D033961:Adaptor Protein Complex 1 / Q000235:genetics* / Q000378:metabolism; D002462:Cell Membrane; D016922:Cellular Senescence / Q000235:genetics*; D002734:Chlorophyll / Q000378:metabolism; D003001:Cloning, Molecular; D017124:Conserved Sequence; D017343:Genes, Plant; D006056:Golgi Apparatus; D026341:Minichromosome Maintenance 1 Protein / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010788:Photosynthesis / Q000502:physiology; D045332:Photosystem II Protein Complex / Q000502:physiology; D010935:Plant Diseases / Q000235:genetics*; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D017382:Reactive Oxygen Species / Q000378:metabolism; D022161:Transport Vesicles; D015003:Yeasts
chemical_list: D033961:Adaptor Protein Complex 1; D026341:Minichromosome Maintenance 1 Protein; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D002734:Chlorophyll