Domestication converts perennial and photoperiodic ancestral cotton to day-neutral cotton varieties, and the selection of short-season cotton varieties is one of the major objectives of cotton breeding. However, little is known about the mechanism of flowering time in cotton. Here, we report a cotton HD-ZIP I-class transcription factor (GhHB12) specifically expressed in axillary buds, which antagonisticlly interacts with GhSPL10/13 to repress the expression of GhFT, GhFUL, and GhSOC1, resulting in bushy architecture and delayed flowering under long-day conditions. We found that GhHB12-mediated ancestral upland cotton phenotypes (bushy architecture and delayed flowering) could be rescued under short-day conditions. We showed that overexpressing of GhrSPL10 partially rescues the bushy architecture and delayed flowering phenotypes, while overexpression of GhmiR157 reinforced these phenotypes in GhHB12-overexpressing plants. This study defines a regulatory module which regulates cotton architecture, phase transition and could be applied in the breeding of early maturing cotton varieties.

中文翻译：

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棉花HD-Zip转录因子GhHB12通过GhmiR157-GhSPL途径调节开花时间和植物结构。

驯化将多年生和光周期祖先的棉花转化为日中性棉花品种，选择短季节的棉花品种是棉花育种的主要目标之一。但是，关于棉花开花时间的机制知之甚少。在这里，我们报告了一个专门在腋芽中表达的棉花HD-ZIP I类转录因子（GhHB12），它与GhSPL10 / 13拮抗相互作用，以抑制GhFT，GhFUL和GhSOC1的表达，从而导致灌木丛状结构和在开花下延迟开花长期的条件。我们发现，GhHB12介导的祖先陆地棉表型（繁忙的结构和延迟的开花）可以在短日条件下得到挽救。我们表明，GhrSPL10的过表达部分拯救了茂密的建筑并延缓了开花表型，而过表达GhmiR157可以增强过表达GhHB12的植物的这些表型。这项研究定义了一个调节模块，该模块可调节棉花的结构，相变，并可用于早期成熟的棉花品种的育种。