title: Spotted leaf11, a negative regulator of plant cell death and defense, encodes a U-box/armadillo repeat protein endowed with E3 ubiquitin ligase activity.
abstract: The rice (Oryza sativa) spotted leaf11 (spl11) mutant was identified from an ethyl methanesulfonate-mutagenized indica cultivar IR68 population and was previously shown to display a spontaneous cell death phenotype and enhanced resistance to rice fungal and bacterial pathogens. Here, we have isolated Spl11 via a map-based cloning strategy. The isolation of the Spl11 gene was facilitated by the identification of three additional spl11 alleles from an IR64 mutant collection. The predicted SPL11 protein contains both a U-box domain and an armadillo (ARM) repeat domain, which were demonstrated in yeast and mammalian systems to be involved in ubiquitination and protein-protein interactions, respectively. Amino acid sequence comparison indicated that the similarity between SPL11 and other plant U-box-ARM proteins is mostly restricted to the U-box and ARM repeat regions. A single base substitution was detected in spl11, which results in a premature stop codon in the SPL11 protein. Expression analysis indicated that Spl11 is induced in both incompatible and compatible rice-blast interactions. In vitro ubiquitination assay indicated that the SPL11 protein possesses E3 ubiquitin ligase activity that is dependent on an intact U-box domain, suggesting a role of the ubiquitination system in the control of plant cell death and defense.
authors.affiliation: Department of Plant Pathology, Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Li-Rong
authors.initials: LR
authors.lastname: Zeng
authors.forename: Shaohong
authors.initials: S
authors.lastname: Qu
authors.forename: Alicia
authors.initials: A
authors.lastname: Bordeos
authors.forename: Chengwei
authors.initials: C
authors.lastname: Yang
authors.forename: Marietta
authors.initials: M
authors.lastname: Baraoidan
authors.forename: Hongyan
authors.initials: H
authors.lastname: Yan
authors.forename: Qi
authors.initials: Q
authors.lastname: Xie
authors.forename: Baek Hie
authors.initials: BH
authors.lastname: Nahm
authors.forename: Hei
authors.initials: H
authors.lastname: Leung
authors.forename: Guo-Liang
authors.initials: GL
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016923:Cell Death / Q000502:physiology*; D032461:Chromosomes, Plant; D017931:DNA Primers; D004331:Drosophila melanogaster; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation; D012275:Oryza; D020161:Physical Chromosome Mapping; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D010940:Plant Proteins; D044767:Ubiquitin-Protein Ligases