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Leaves are the primary structures responsible for photosynthesis, making leaf morphology one of the most important traits of rice plant architecture. Both plant architecture and nutrient utilization jointly affect rice yield, however, their molecular association is still poorly understood. We identified a rice mutant, leaf width 5 (lw5), that displayed small grains and wide leaves and possesses characteristics typical of a small “sink” and a large “source”. Map-based cloning and CRISPR-Cas9 gene editing indicated that LW5 affects both the plant architecture and yield. It is an allele of D1, encoding the rice G protein α subunit. The loss of LW5 functioning leads to an increase in the rate of photosynthesis, vascular bundles, and chlorophyll content. However, the grain-straw ratio and the rate of grain filling decreased significantly. The detection results of 15N-ammonium nitrate and an expression analysis of genes associated with nitrogen demonstrated that LW5 serves an important role in nitrate uptake and transport. LW5 affects plant architecture and grain size by regulating nitrogen transfer. These results provide a theoretical foundation for further research surrounding the molecular mechanism of “source-sink” balance in rice and suggest novel methods of molecular design for the cultivation of breeding super rice in ideal plant types. https://www./science/article/pii/S0981942820305477  版权作品，未经PaperRSS书面授权，严禁转载，违者将被追究法律责任。 PaperRSS，关注生命科学，高校院所科研进展。 |
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叶片是光合作用的主要结构，叶片形态是水稻植株结构的重要特征之一。植株结构和养分利用共同影响水稻产量，但它们之间的分子联系仍不清楚。我们鉴定了一个水稻突变体，叶宽5(Lw5)，表现出小粒宽叶，具有典型的小“库”和大“源”的特征。图位克隆和CRISPR-Cas9基因编辑表明，LW5对植株构型和产量均有影响。它是D1的等位基因，编码水稻G蛋白α亚基。LW5功能的丧失导致光合作用速率、维管束和叶绿素含量的增加。而籽粒/秸秆比和灌浆速率则显著下降。15N-硝酸铵的检测结果和与氮相关的基因表达分析表明，LW5在硝酸盐的吸收和运输中起着重要的作用。LW5通过调节氮素转运影响植株结构和籽粒大小。这些结果为进一步研究水稻“源库”平衡的分子机制提供了理论基础，并为培育理想株型超级稻提供了新的分子设计方法。
