Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, China.
The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
Mol Plant. 2021 Oct 4;14(10):1699-1713. doi: 10.1016/j.molp.2021.06.027. Epub 2021 Jun 30.
G-protein signaling and ubiquitin-dependent degradation are both involved in grain development in rice, but how these pathways are coordinated in regulating this process is unknown. Here, we show that Chang Li Geng 1 (CLG1), which encodes an E3 ligase, regulates grain size by targeting the Gγ protein GS3, a negative regulator of grain length, for degradation. Overexpression of CLG1 led to increased grain length, while overexpression of mutated CLG1 with changes in three conserved amino acids decreased grain length. We found that CLG1 physically interacts with and ubiquitinats GS3which is subsequently degraded through the endosome degradation pathway, leading to increased grain size. Furthermore, we identified a critical SNP in the exon 3 of CLG1 that is significantly associated with grain size variation in a core collection of cultivated rice. This SNP results in an amino acid substitution from Arg to Ser at position 163 of CLG1 that enhances the E3 ligase activity of CLG1 and thus increases rice grain size. Both the expression level of CLG1 and the SNP CLG1 may be useful variations for manipulating grain size in rice.
G 蛋白信号转导和泛素依赖性降解都参与了水稻籽粒发育，但这些途径如何协调调节这一过程尚不清楚。在这里，我们发现编码 E3 连接酶的 Chang Li Geng 1 (CLG1) 通过靶向 GS3 进行降解来调节粒长，GS3 是籽粒长度的负调控因子。CLG1 的过表达导致粒长增加，而改变三个保守氨基酸的突变型 CLG1 的过表达导致粒长减小。我们发现 CLG1 与 GS3 相互作用，并泛素化 GS3，随后通过内体降解途径降解，导致粒长增加。此外，我们在 CLG1 的外显子 3 中鉴定出一个关键 SNP，该 SNP 与栽培稻核心群体的粒长变异显著相关。该 SNP 导致 CLG1 第 163 位的氨基酸从精氨酸突变为丝氨酸，增强了 CLG1 的 E3 连接酶活性，从而增加了水稻粒长。CLG1 的表达水平和 SNP CLG1 可能是操纵水稻粒长的有用变异。
