Selection for favorable inflorescence architecture to improve yield is one of the crucial targets in crop breeding. Different tomato varieties require distinct inflorescence-branching structures to enhance productivity. While a few important genes for tomato inflorescence-branching development have been identified, the regulatory mechanism underlying inflorescence branching is still unclear. Here, we confirmed that SISTER OF TM3 (STM3), a homolog of Arabidopsis SOC1, is a major positive regulatory factor of tomato inflorescence architecture by map-based cloning. High expression levels of STM3 underlie the highly inflorescence-branching phenotype in ST024. STM3 is expressed in both vegetative and reproductive meristematic tissues and in leaf primordia and leaves, indicative of its function in flowering time and inflorescence-branching development. Transcriptome analysis shows that several floral development-related genes are affected by STM3 mutation. Among them, FRUITFULL1 (FUL1) is downregulated in stm3cr mutants, and its promoter is bound by STM3 by ChIP-qPCR analysis. EMSA and dual-luciferase reporter assays further confirmed that STM3 could directly bind the promoter region to activate FUL1 expression. Mutation of FUL1 could partially restore inflorescence-branching phenotypes caused by high STM3 expression in ST024. Our findings provide insights into the molecular and genetic mechanisms underlying inflorescence development in tomato.

中文翻译：

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TM3 SISTER 激活 FRUITFULL1 调节番茄的花序分枝

选择有利的花序结构以提高产量是作物育种的关键目标之一。不同的番茄品种需要不同的花序分支结构来提高生产力。虽然已经确定了一些番茄花序分枝发育的重要基因，但花序分枝的调控机制仍不清楚。在这里，我们确认了 SISTER OF TM3 (STM3)，拟南芥SOC1 是基于图谱克隆的番茄花序结构的主要正调控因子。的高表达水平STM3是 ST024 中高度花序分枝表型的基础。STM3在营养和生殖分生组织以及叶原基和叶片中表达，表明其在开花时间和花序分枝发育中的功能。转录组分析表明，几个与花发育相关的基因受STM3突变。他们之中，FRUITFULL1(FUL1) 被下调stm3cr突变体，其启动子通过 ChIP-qPCR 分析与 STM3 结合。EMSA 和双荧光素酶报告基因分析进一步证实 STM3 可以直接结合启动子区域以激活FUL1表达。的突变FUL1可以部分恢复由高STM3ST024 中的表达式。我们的研究结果为番茄花序发育的分子和遗传机制提供了见解。