背景:冬小麦经过春化,长时间暴露在低温下激活的过程。在这个阶段,开花信号产生并传输到顶端分生组织,刺激向花序分生组织的过渡,同时抑制分till芽伸长。虽然一些春化基因已经被鉴定,小麦中控制这一过程的关键顺式调控元件和精确机制仍然未知。
结果:在这项研究中,我们构建了跨多个组织的广泛的表观基因组和转录组学分析-叶,腋芽,在冬小麦春化期间,茎尖。表观遗传修饰在春化过程中引起组织特异性反应和亚基因组差异表达中起着至关重要的作用。值得注意的是,我们观察到H3K27me3主要调节春化诱导基因,对春化抑制基因的影响有限。这些数据集的整合可以识别10,600个推定的春化相关调控元件,包括位于VRN3上游30Kb的远端可接近染色质区(ACR),有助于构建全面的调控网络。此外,我们发现TaSPL7/15,衰老相关开花途径的组成部分,与VRN1启动子和VRN3远端调控元件相互作用。这些相互作用精细地调节他们的表达,从而影响春化过程和开花。
结论:我们的研究为小麦春化的表观基因组动力学提供了重要的见解,并确定了对开发具有不同春化特征的小麦种质至关重要的推定调控元件。它还建立了一个与春化相关的转录网络,并揭示来自衰老途径的TaSPL7/15通过直接结合VRN1启动子和VRN3远端调控元件参与春化。
BACKGROUND: Winter wheat undergoes vernalization, a process activated by prolonged exposure to low temperatures. During this phase, flowering signals are generated and transported to the apical meristems, stimulating the transition to the inflorescence meristem while inhibiting tiller bud elongation. Although some vernalization genes have been identified, the key cis-regulatory elements and precise mechanisms governing this process in wheat remain largely unknown.
RESULTS: In this study, we construct extensive epigenomic and transcriptomic profiling across multiple tissues-leaf, axillary bud, and shoot apex-during the vernalization of winter wheat. Epigenetic modifications play a crucial role in eliciting tissue-specific responses and sub-genome-divergent expressions during vernalization. Notably, we observe that H3K27me3 primarily regulates vernalization-induced genes and has limited influence on vernalization-repressed genes. The integration of these datasets enables the identification of 10,600 putative vernalization-related regulatory elements including distal accessible chromatin regions (ACRs) situated 30Kb upstream of VRN3, contributing to the construction of a comprehensive regulatory network. Furthermore, we discover that TaSPL7/15, integral components of the aging-related flowering pathway, interact with the VRN1 promoter and VRN3 distal regulatory elements. These interactions finely regulate their expressions, consequently impacting the vernalization process and flowering.
CONCLUSIONS: Our study offers critical insights into wheat vernalization\'s epigenomic dynamics and identifies the putative regulatory elements crucial for developing wheat germplasm with varied vernalization characteristics. It also establishes a vernalization-related transcriptional network, and uncovers that TaSPL7/15 from the aging pathway participates in vernalization by directly binding to the VRN1 promoter and VRN3 distal regulatory elements.