GRAIN SIZE AND NUMBER1 Negatively Regulates the OsMKKK10-OsMKK4-OsMPK6 Cascade to Coordinate the Trade-off between Grain Number per Panicle and Grain Size in Rice
GRAIN SIZE AND NUMBER1 Negatively Regulates the OsMKKK10-OsMKK4-OsMPK6 Cascade to Coordinate the Trade-off between Grain Number per Panicle and Grain Size in Rice
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DOI：
10.1105/tpc.17.00959
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发表时间：
2018-04-01
期刊：
影响因子：
11.6
通讯作者：
Lin, Hong-Xuan
中科院分区：
文献类型：
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作者：
Guo, Tao;Chen, Ke;Lin, Hong-Xuan
籽粒数量和大小是决定粮食产量的互作农艺性状。然而，负责协调这些性状之间权衡的分子机制仍然难以捉摸。在这里，我们描述了水稻(Oryza Sativa)的粒大小和1号(Gsn1)突变体，它比野生型的籽粒更大，但由于细胞分化和增殖的无序定位，穗子更稀疏。GSN1编码丝裂原活化蛋白激酶磷酸酶OsMKP1，这是一种功能未知的双特异性磷酸酶。GSN1表达降低会导致颗粒变大变少，而GSN1表达增加则会导致颗粒增多但颗粒尺寸变小。GSN1通过去磷酸化直接与丝裂原激活的蛋白激酶OsMPK6相互作用并使其失活。与这一发现一致的是，分别抑制有丝分裂原激活蛋白激酶基因OsMPK6、OsMKK4和OsMKKK10导致更致密的圆锥花序和更小的颗粒，从而挽救了突变的gsN1表型。因此，OsMKKK10-OsMKK4-OsMPK6参与了水稻的穗部形态发生，并通过共同的途径发挥作用。我们证实GSN1是决定穗构型的OsMKKK10-OsMKK4-OsMPK6级联反应的负调控因子。GSN1-MAPK模块通过整合局部细胞分化和增殖来协调颗粒数量和颗粒大小之间的权衡。这些发现为了解穗的发育可塑性和提高作物产量的潜在手段提供了重要的见解。
Grain number and size are interactive agronomic traits that determine grain yield. However, the molecular mechanisms responsible for coordinating the trade-off between these traits remain elusive. Here, we characterized the rice ( Oryza sativa) grain size and number1 (gsn1) mutant, which has larger grains but sparser panicles than the wild type due to disordered localized cell differentiation and proliferation. GSN1 encodes the mitogen-activated protein kinase phosphatase OsMKP1, a dual-specificity phosphatase of unknown function. Reduced expression of GSN1 resulted in larger and fewer grains, whereas increased expression resulted in more grains but reduced grain size. GSN1 directly interacts with and inactivates the mitogen-activated protein kinase OsMPK6 via dephosphorylation. Consistent with this finding, the suppression of mitogen-activated protein kinase genes OsMPK6, OsMKK4, and OsMKKK10 separately resulted in denser panicles and smaller grains, which rescued the mutant gsn1 phenotypes. Therefore, OsMKKK10-OsMKK4-OsMPK6 participates in panicle morphogenesis and acts on a common pathway in rice. We confirmed that GSN1 is a negative regulator of the OsMKKK10-OsMKK4-OsMPK6 cascade that determines panicle architecture. The GSN1-MAPK module coordinates the trade-off between grain number and grain size by integrating localized cell differentiation and proliferation. These findings provide important insights into the developmental plasticity of the panicle and a potential means to improve crop yields.