Mitochondria-Associated Pyruvate Kinase Complexes Regulate Grain Filling in Rice1
Mitochondria-Associated Pyruvate Kinase Complexes Regulate Grain Filling in Rice1
复制标题
线粒体相关丙酮酸激酶复合物调节水稻籽粒灌浆
DOI：
10.1104/pp.20.00279
复制
发表时间：
2020-07-01
期刊：
影响因子：
7.4
通讯作者：
Li, Shigui
中科院分区：
文献类型：
--
作者：
Hu, Li;Tu, Bin;Li, Shigui
水稻籽粒灌浆是一个复杂的农艺性状，直接决定着水稻的粒重和品质。然而，影响籽粒灌浆的关键因素仍然知之甚少。在这里，我们确定了一个灌浆基因，OsPK 3，编码丙酮酸激酶（PK）。OsPK 3在水稻中组成型表达，但在叶片和发育中的颖果中表达量相对较高，在Suc转运和卸载相关组织中特异表达信号，支持其通过影响Suc转运调控籽粒灌浆的生物学功能。OsPK 3的亚细胞定位分析显示其与线粒体的关联，并且OsPK 3在体内与另外两种PK同工酶OsPK 1和OsPK 4物理相互作用并形成异二聚体。OsPK 1和OsPK 4定位于线粒体和胞质溶胶，并被OsPK 3募集到线粒体。尽管OsPK 1和OsPK 4具有高度的序列相似性，但它们具有不同的表达模式。OsPK 1的破坏导致多效缺陷，OsPK 4的功能丧失导致严重的垩白粒，而没有其他明显的缺陷。总的来说，我们发现，两个水稻相关的丙酮酸激酶复合物，OsPK 3-OsPK 1/OsPK 4，参与调节籽粒灌浆的阶段特异性微调Suc易位。
Mitochondrial complexes regulate grain filling by fine-tuning sucrose translocation in rice.Grain filling is a complex agronomic trait that directly determines grain weight and quality in rice (Oryza sativa). Nevertheless, key factors affecting grain filling remain poorly understood. Here, we identified a grain filling gene,OsPK3, encoding a pyruvate kinase (PK). The loss of function ofOsPK3caused reduced PK activity and Suc translocation defects from source to sink in rice, which led to compromised grain filling.OsPK3was constitutively expressed but had relatively higher expression levels in leaf and developing caryopsis and specific expression signals in tissues involved in Suc transport and unloading, supporting its biological function in regulation of grain filling by affecting Suc translocation. Subcellular localization analysis of OsPK3 revealed its association with mitochondria, and OsPK3 physically interacted and formed heterodimers in vivo with two other PK isozymes, OsPK1 and OsPK4. Both OsPK1 and OsPK4 localized to the mitochondria and cytosol and were recruited to the mitochondria by OsPK3. Despite their high sequence similarity, OsPK1 and OsPK4 had distinct expression patterns. As observed forospk3, disruption ofOsPK1caused pleiotropic defects, whileOsPK4loss of function led to severely chalky grains without other obvious defects. Collectively, we revealed that two mitochondria-associated pyruvate kinase complexes, OsPK3-OsPK1/OsPK4, are involved in regulation of grain filling by stage-specific fine-tuning of Suc translocation.