Spotted leaf11, a negative regulator of plant cell death and defense, encodes a U-box/armadillo repeat protein endowed with E3 ubiquitin ligase activity.
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.
Zeng
Li-Rong
LR
Department of Plant Pathology, Ohio State University, Columbus, Ohio 43210, USA.
Qu
Shaohong
S
Bordeos
Alicia
A
Yang
Chengwei
C
Baraoidan
Marietta
M
Yan
Hongyan
H
Xie
Qi
Q
Nahm
Baek Hie
BH
Leung
Hei
H
Wang
Guo-Liang
GL
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*
D017931:DNA Primers; D010940:Plant Proteins; D044767:Ubiquitin-Protein Ligases