Variation in the regulatory region of FZP causes increases in secondary inflorescence branching and grain yield in rice domestication
Variation in the regulatory region of FZP causes increases in secondary inflorescence branching and grain yield in rice domestication
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DOI：
10.1111/tpj.14062
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发表时间：
2018-11-01
期刊：
影响因子：
7.2
通讯作者：
Zhu, Zuofeng
中科院分区：
文献类型：
--
作者：
Huang, Yongyu;Zhao, Shuangshuang;Zhu, Zuofeng
花序分枝是决定水稻产量的重要农艺性状。普通野生稻（Oryza rufipogon Griff.）由于最小的二次分枝，很少有谷粒。相比之下，水稻品种已被选择产生大圆锥花序与更多的二次分枝。本研究表明，与FZP基因相同的COS1基因在野生稻二次分枝数少到栽培稻二次分枝数多的关键转变中起着重要作用。FZP基因上游约2.7kb处的一个4bp串联重复序列缺失可能影响生长素反应因子与FZP启动子的结合活性，降低FZP基因的表达水平，显著提高栽培稻二次分枝数和产量。功能分析表明，窄叶1（NAL1），胰蛋白酶样丝氨酸和半胱氨酸蛋白酶，与FZP相互作用，并促进其降解。因此，下调FZP表达或上调NAL1表达均能增加中花17的穗二次分枝数、穗粒数和单株产量。本研究不仅为水稻驯化过程中粒数和产量增加的分子机制提供了新的认识，而且为水稻产量的改良提供了有利基因。
Inflorescence branching is a key agronomic trait determining rice yield. The primary branch of the ancestral wild rice (Oryza rufipogon Griff.) bears few grains, due to minimal secondary branching. By contrast, Oryza sativa cultivars have been selected to produce large panicles with more secondary branches. Here we showed that the CONTROL OF SECONDARY BRANCH 1 (COS1) gene, which is identical to FRIZZY PANICLE (FZP), plays an important role in the key transition from few secondary branches in wild rice to more secondary branches in domesticated rice cultivars. A 4-bp tandem repeat deletion approximately 2.7 kb upstream of FZP may affect the binding activities of auxin response factors to the FZP promoter, decrease the expression level of FZP and significantly enhance the number of secondary branches and grain yield in cultivated rice. Functional analyses showed that NARROW LEAF 1 (NAL1), a trypsin-like serine and cysteine protease, interacted with FZP and promoted its degradation. Consistently, downregulating FZP expression or upregulating NAL1 expression in the commercial cultivar Zhonghua 17 increased the number of secondary branches per panicle, grain number per panicle and grain yield per plant. Our findings not only provide insights into the molecular mechanism of increasing grain number and yield during rice domestication, but also offer favorable genes for improving the grain yield of rice.