The F-Box Protein OsFBK12 Targets OsSAMS1 for Degradation and Affects Pleiotropic Phenotypes, Including Leaf Senescence, in Rice
The F-Box Protein OsFBK12 Targets OsSAMS1 for Degradation and Affects Pleiotropic Phenotypes, Including Leaf Senescence, in Rice
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DOI：
10.1104/pp.113.224527
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发表时间：
2013-12-01
期刊：
影响因子：
7.4
通讯作者：
Chong, Kang
中科院分区：
文献类型：
--
作者：
Chen, Yuan;Xu, Yunyuan;Chong, Kang
叶片衰老与籽粒灌浆速率和粒重有关。在遗传或生理水平上参与衰老调节的许多成分是已知的。然而，对分子调控机制知之甚少。在这里，我们报道了OsFBK12（一种含有Kelch重复基序的F-box蛋白）与S-ADENOSYL-L-METHIONINE SYNTHETASE1 （SAMS1）相互作用，调节水稻（Oryza sativa）叶片衰老、种子大小和籽粒数。酵母双杂交、下拉和双分子荧光互补实验表明，OsFBK12与Oryza sativa S-PHASE KINASE-ASSOCIATED PROTEIN1-LIKE蛋白和OsSAMS1相互作用。生化和生理数据表明OsFBK12能够靶向OsSAMS1进行降解。OsFBK12-RNA干扰系和OsSAMS1过表达系乙烯水平升高，OsFBK12-OX系和OsSAMS1- rna干扰株乙烯水平降低。表型上，OsFBK12的过表达导致叶片衰老和发芽延迟，种子大小增加，而OsFBK12或OsSAMS1的敲低均促进了衰老程序。我们的研究结果表明，OsFBK12通过与Oryza sativa S-PHASE KINASE-ASSOCIATED PROTEIN1-LIKE PROTEIN相互作用参与26S蛋白酶体途径，并针对底物OsSAMS1进行降解，引发乙烯水平的变化，从而调节叶片衰老和晶粒大小。这些数据在水稻分子育种中具有潜在的应用价值。
Leaf senescence is related to the grain-filling rate and grain weight in cereals. Many components involved in senescence regulation at either the genetic or physiological level are known. However, less is known about molecular regulation mechanisms. Here, we report that OsFBK12 (an F-box protein containing a Kelch repeat motif) interacts with S-ADENOSYL-L-METHIONINE SYNTHETASE1 (SAMS1) to regulate leaf senescence and seed size as well as grain number in rice (Oryza sativa). Yeast two-hybrid, pull-down, and bimolecular fluorescence complementation assays indicate that OsFBK12 interacts with Oryza sativa S-PHASE KINASE-ASSOCIATED PROTEIN1-LIKE PROTEIN and with OsSAMS1. Biochemical and physiological data showed that OsFBK12 targets OsSAMS1 for degradation. OsFBK12-RNA interference lines and OsSAMS1 overexpression lines showed increased ethylene levels, while OsFBK12-OX lines and OsSAMS1-RNA interference plants exhibited decreased ethylene. Phenotypically, overexpression of OsFBK12 led to a delay in leaf senescence and germination and increased seed size, whereas knockdown lines of either OsFBK12 or OsSAMS1 promoted the senescence program. Our results suggest that OsFBK12 is involved in the 26S proteasome pathway by interacting with Oryza sativa S-PHASE KINASE-ASSOCIATED PROTEIN1-LIKE PROTEIN and that it targets the substrate OsSAMS1 for degradation, triggering changes in ethylene levels for the regulation of leaf senescence and grain size. These data have potential applications in the molecular breeding of rice.