Transcriptional silencer and copy number variants (CNVs) are associated with gene expression. However, their roles in generating phenotypes have not been well studied. Here we identified a rice quantitative trait locus, SGDP7 (Small Grain and Dense Panicle 7). SGDP7 is identical to FZP (FRIZZY PANICLE), which represses the formation of axillary meristems. The causal mutation of SGDP7 is an 18-bp fragment, named CNV-18bp, which was inserted ~5.3 kb upstream of FZP and resulted in a tandem duplication in the cultivar Chuan 7. The CNV-18bp duplication repressed FZP expression, prolonged the panicle branching period and increased grain yield by more than 15% through substantially increasing the number of spikelets per panicle (SPP) and slightly decreasing the 1,000-grain weight (TGW). The transcription repressor OsBZR1 binds the CGTG motifs in CNV-18bp and thereby represses FZP expression, indicating that CNV-18bp is the upstream silencer of FZP. These findings showed that the silencer CNVs coordinate a trade-off between SPP and TGW by fine-tuning FZP expression, and balancing the trade-off could enhance yield potential.

中文翻译：

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重复使用FZP的上游消音器可提高水稻的籽粒产量。

转录沉默子和拷贝数变异体（CNV）与基因表达相关。但是，它们在产生表型中的作用尚未得到很好的研究。在这里，我们确定了水稻的数量性状基因座SGDP7（小粒和密集穗7）。SGDP7与FZP（FRIZZY PANICLE）相同，后者可抑制腋生分生组织的形成。SGDP7的因果突变是一个18 bp的片段，称为CNV-18bp，该片段在FZP上游〜5.3 kb处插入，并导致传代品种Chuan 7发生串联复制。CNV-18bp的复制抑制FZP表达，从而延长了穗部。通过显着增加每穗小穗数（SPP）并略微降低1,000粒重（TGW），使分枝期和谷物产量提高了15％以上。转录阻遏物OsBZR1结合CNV-18bp中的CGTG基序，从而抑制FZP表达，表明CNV-18bp是FZP的上游沉默子。这些发现表明，消音器CNV通过微调FZP表达来协调SPP和TGW之间的折衷，平衡折衷可以提高产量潜力。