Os09g0532000
The rice gene Os09g0532000 was reported as sgr in 2007[1] by researchers from Korea.
Contents
Annotated Information
Gene Symbol
- Os09g0532000 <=> sgr(t), sgr, OsSGR
Function
- Sgr is a senescence-associated gene encoding a novel chloroplast protein.
- In senescing leaves, Sgr regulates Chl degradation by inducing LHCPII disassembly through direct interaction, leading to the degradation of Chls and Chl-free LHCPII by catabolic enzymes and proteases, respectively.
Mutation
- Transgenic rice overexpressing Sgr produces yellowish-brown leaves, and Arabidopsis thaliana pheophorbide a oxygenase–impaired mutants exhibiting a stay-green phenotype during dark-induced senescence have reduced expression of Sgr homologs, indicating that Sgr regulates Chl degradation at the transcriptional level. The researchers show that the leaf staygreenness of the sgr mutant is associated with a failure in the destabilization of the light-harvesting chlorophyll binding protein (LHCP) complexes of the thylakoid membranes, which is a prerequisite event for the degradation of Chls and LHCPs during senescence. Transient overexpression of Sgr in Nicotiana benthamiana and an in vivo pull-down assay show that Sgr interacts with LHCPII, indicating that the Sgr-LHCPII complexes are formed in the thylakoid membranes.
Figure 1. Phenotypic Characterization of sgr during Natural and Dark-Induced Senescence. [1].
Sublocalization
- The researchers introduced Pro35S:Sgr- GFP into protoplasts of Arabidopsis and showed that the green fluorescence by GFP colocalized with the red autofluorescence of Chls, indicating that Sgr is a chloroplast protein
Evolution
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Labs working on this gene
- Department of Plant Science and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul
151-921, Korea
- Graduate School of Biotechnology and Plant Metabolism Research Center, Kyung Hee University, Yongin 449-701, Korea
- Department of Biology, Chungnam National University, Daejeon 305-764, Korea
References
