Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044, China.
Int J Mol Sci. 2022 Feb 21;23(4):2347. doi: 10.3390/ijms23042347.
Grain weight, a crucial trait that determines the grain yield in rice, is influenced by grain size. Although a series of regulators that control grain size have been identified in rice, the mechanisms underlying grain development are not yet well understood. In this study, we identified OsPUB43, a U-box E3 ubiquitin ligase, as an important negative regulator determining the gain size and grain weight in rice. Phenotypes of large grain are observed in mutants, whereas overexpression of results in short grains. Scanning electron microscopy analysis reveals that modulates the grain size mainly by inhibiting cell proliferation in the spikelet hull. The OsPUB43 protein is localized in the cytoplasm and nucleus. The mutants display high sensitivity to exogenous BR, while -OE lines are hyposensitive to BR. Furthermore, the transient transcriptional activity assay shows that OsBZR1 can activate the expression of . Collectively, our results indicate that OsPUB43 negatively controls the gain size by modulating the expression of BR-responsive genes as well as MADS-box genes that are required for lemma/palea specification, suggesting that OsPUB43 has a potential valuable application in the enlargement of grain size in rice.
粒重是决定水稻产量的关键性状，受粒型的影响。尽管已经在水稻中鉴定出一系列控制粒型的调节因子，但粒发育的机制尚不清楚。在这项研究中，我们鉴定了 OsPUB43，一种 U-box E3 泛素连接酶，是决定水稻粒型和粒重的重要负调控因子。 在 突变体中观察到大粒的表型，而 的过表达导致短粒。扫描电子显微镜分析表明， 主要通过抑制小穗颖壳中的细胞增殖来调节粒型。OsPUB43 蛋白定位于细胞质和细胞核。 突变体对外源 BR 表现出高敏感性，而 -OE 系对 BR 表现出低敏感性。此外，瞬时转录活性测定表明 OsBZR1 可以激活 的表达。综上所述，我们的结果表明，OsPUB43 通过调节 BR 响应基因以及 MADS-box 基因的表达来负调控粒型，这些基因对于外稃/内稃的特化是必需的，这表明 OsPUB43 在水稻粒型增大方面具有潜在的应用价值。
