MiR408 Regulates Grain Yield and Photosynthesis via a Phytocyanin Protein
MiR408 Regulates Grain Yield and Photosynthesis via a Phytocyanin Protein
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MiR408 通过植物青素蛋白调节谷物产量和光合作用
DOI：
10.1104/pp.17.01169
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发表时间：
2017-11-01
期刊：
影响因子：
7.4
通讯作者：
Chen, Yue-Qin
中科院分区：
文献类型：
--
作者：
Zhang, Jin-Ping;Yu, Yang;Chen, Yue-Qin
提高粮食产量是作物育种的首要目标。在这里，我们报道了一种保守的microRNA OsmiR408的表达上调，可以通过增加穗部分枝和粒数来正向调节水稻的产量。我们进一步证明，OsmiR408通过下调其下游靶基因OsUCL8来调节粮食产量，OsUCL8是藻蓝蛋白家族的一个uclacyanin(UCL)基因。OsUCL8基因的敲除或敲除也增加了籽粒产量，而OsUCL8基因的过度表达导致了相反的表型。时空表达分析表明，OsUCL8在雌蕊、幼穗、发育中的种子和花序分生组织中高表达，与OsmiR408几乎互补。有趣的是，OsUCL8蛋白定位于细胞质，与大多数定位于质膜的藻蓝蛋白不同。进一步的研究表明，miR408对OsUCL8的切割影响了植物细胞中铜的动态平衡，进而影响了水稻叶绿体蛋白的丰度和光合作用。据我们所知，这是首次报道miR408-OsUCL8对水稻光合作用和产量的调节作用。我们的研究进一步拓宽了microRNAs和UCLs的研究前景，为利用基因工程培育高产作物提供了重要信息。
Increasing grain yield is the most important object of crop breeding. Here, we report that the elevated expression of a conserved microRNA, OsmiR408, could positively regulate grain yield in rice (Oryza sativa) by increasing panicle branches and grain number. We further showed that OsmiR408 regulates grain yield by down-regulating its downstream target, OsUCL8, which is an uclacyanin (UCL) gene of the phytocyanin family. The knock down or knock out of OsUCL8 also increases grain yield, while the overexpression of OsUCL8 results in an opposite phenotype. Spatial and temporal expression analyses showed that OsUCL8 was highly expressed in pistils, young panicles, developing seeds, and inflorescence meristem and was nearly complementary to that of OsmiR408. Interestingly, the OsUCL8 protein was localized to the cytoplasm, distinct from a majority of phytocyanins, which localize to the plasma membrane. Further studies revealed that the cleavage of OsUCL8 by miR408 affects copper homeostasis in the plant cell, which, in turn, affects the abundance of plastocyanin proteins and photosynthesis in rice. To our knowledge, this is the first report of the effects of miR408-OsUCL8 in regulating rice photosynthesis and grain yield. Our study further broadens the perspective of microRNAs and UCLs and provides important information for breeding high-yielding crops through genetic engineering.