• TaVrn1, encoding a MADS-box transcription factor (TF), is the central regulator of wheat vernalization-induced flowering. Considering that the MADS-box TF usually works by forming hetero- or homodimers, we conducted yeast-two-hybrid screening and identified an SVP-like MADS-box protein TaVrt2 interacting with TaVrn1. However, the specific function of TaVrt2 and the biological implication of its interaction with TaVrn1 remained unknown.
• We validated the function of TaVrt2 and TaVrn1 by wheat transgenic experiments and their interaction through multiple protein-binding assays. Population genetic analysis also was used to display their interplay. Transcriptomic sequencing and chromatin immunoprecipitation assays were performed to identify their common targets.
• TaVrt2 and TaVrn1 are flowering promoters in the vernalization pathway and interact physically in vitro, in planta and in wheat cells. Additionally, TaVrt2 and TaVrn1 were significantly induced in leaves by vernalization, suggesting their spatio-temporal interaction during vernalization. Genetic analysis indicated that TaVrt2 and TaVrn1 had significant epistatic effects on flowering time. Furthermore, native TaVrn1 was up-regulated significantly in TaVrn1-OE (overexpression) and TaVrt2-OE lines. Moreover, TaVrt2 could bind with TaVrn1 promoter directly.
• A TaVrt2-mediated positive feedback loop of TaVrn1 during vernalization was proposed, providing additional understanding on the regulatory mechanism underlying vernalization-induced flowering.

中文翻译：

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TaVrt2 是一种 SVP 样基因，与 TaVrn1 合作调节小麦春化诱导的开花

• TaVrn1编码 MADS-box 转录因子 (TF)，是小麦春化诱导开花的中心调节因子。考虑到 MADS-box TF 通常通过形成异源二聚体或同源二聚体来发挥作用，我们进行了酵母双杂交筛选并鉴定了一种与 TaVrn1 相互作用的 SVP 样 MADS-box 蛋白 TaVrt2。然而，TaVrt2 的具体功能及其与 TaVrn1 相互作用的生物学意义仍然未知。
• 我们通过小麦转基因实验验证了 TaVrt2 和 TaVrn1 的功能，并通过多种蛋白质结合测定验证了它们的相互作用。种群遗传分析也被用来显示它们的相互作用。进行了转录组测序和染色质免疫沉淀分析以确定它们的共同目标。
• TaVrt2 和 TaVrn1 是春化途径中的开花启动子，并在体外、植物和小麦细胞中发生物理相互作用。此外，春化过程显着诱导了叶片中的TaVrt2和TaVrn1，表明它们在春化过程中存在时空相互作用。遗传分析表明，TaVrt2和TaVrn1对开花时间具有显着的上位效应。此外，天然TaVrn1在TaVrn1 -OE（过表达）和TaVrt2 -OE 系中显着上调。此外，TaVrt2 可以直接与TaVrn1启动子结合。
• 一个TaVrt2介导的正反馈回路TaVrn1春化过程中提出，对监管机制提供额外理解底层春化诱导开花。