SCF(SLF)-mediated cytosolic degradation of S-RNase is required for cross-pollen compatibility in S-RNase-based self-incompatibility in Petunia hybrida
Autor: | Junhui Li, Qun Li, Yongbiao Xue, Yanzhai Song, Yue Zhang, Wei Liu, Jiangbo Fan |
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Rok vydání: | 2013 |
Předmět: |
Gynoecium
Pollination lcsh:QH426-470 Plant Science Biology medicine.disease_cause self-incompatibility Pollen Skp1 medicine Genetics cross-pollen compatibility Original Research Article Genetics (clinical) food and beverages SCFSLF Compartmentalization (psychology) biology.organism_classification Ubiquitin ligase Cell biology lcsh:Genetics S-RNase localization biology.protein self-pollen incompatibility Molecular Medicine Pollen tube ubiquitin/26S proteasome system Solanaceae |
Zdroj: | Frontiers in Genetics Frontiers in Genetics, Vol 5 (2014) |
ISSN: | 1664-8021 |
Popis: | Many flowering plants adopt self-incompatibility (SI) to maintain their genetic diversity. In species of Solanaceae, Plantaginaceae and Rosaceae, SI is genetically controlled by a single S-locus with multiple haplotypes. The S-locus has been shown to encode S-RNases expressed in pistil and multiple SLF (S-locus F-box) proteins in pollen controlling the female and male specificity of SI, respectively. S-RNases appear to function as a cytotoxin to reject self-pollen. In addition, SLFs have been shown to form SCF (SKP1/Cullin1/F-box) complexes to serve as putative E3 ubiquitin ligase to interact with S-RNases. Previously, two different mechanisms, the S-RNase degradation and the S-RNase compartmentalization, have been proposed as the restriction mechanisms of S-RNase cytotoxicity allowing compatible pollination. In this study, we have provided several lines of evidence in support of the S-RNase degradation mechanism by a combination of cellular, biochemical and molecular biology approaches. First, both immunogold labeling and subcellular fractionation assays showed that two key pollen SI factors, PhSLF-S3L and PhSSK1 (SLF-interacting SKP1-like1) from Petunia hybrida, a Solanaceous species, are co-localized in cytosols of both pollen grains and tubes. Second, PhS3L-RNases are mainly detected in the cytosols of both self and non-self pollen tubes after pollination. Third, we found that both PhS3-RNases and PhS3L-RNases directly interact with PhSLF-S3L by yeast two-hybrid and co-immunoprecipitation assays. Fourth, S-RNases are specifically degraded in compatible pollen tubes by non-self SLF action. Taken together, our results demonstrate that SCFSLF-mediated non-self S-RNase degradation occurs in the cytosol of pollen tube through the ubiquitin/26S proteasome system serving as the major mechanism to neutralize S-RNase cytotoxicity during compatible pollination in P. hybrida. |
Databáze: | OpenAIRE |
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