Buzas Diana Mihaela, Nishio Haruki, Kudoh Hiroshi
Faculty of Life and Environmental Sciences, Tsukuba-Plant Innovation Research Center, University of Tsukuba, Tsukuba, Japan.
Center for Ecological Research, Kyoto University, Otsu, Japan.
Front Plant Sci. 2021 Mar 11;12:640442. doi: 10.3389/fpls.2021.640442. eCollection 2021.
Many plant species overwinter before they flower. Transition to flowering is aligned to the seasonal transition as a response to the prolonged cold in winter by a process called vernalization. Multiple well-documented vernalization properties in crucifer species with diverse life histories are derived from environmental regulation of a central inhibitor of the flowering gene, (). Episode(s) of flowering are prevented during high expression and enabled during low expression. repression outlasts the winter to coincide with spring; this heterochronic aspect is termed "winter memory." In the annual , winter memory has long been associated with the highly conserved histone modifiers Polycomb and Trithorax, which have antagonistic roles in transcription. However, there are experimental limitations in determining how dynamic, heterogenous histone modifications within the locus generate the final transcriptional output. Recent theoretical considerations on cell-to-cell variability in gene expression and histone modifications generating bistable states brought support to the hypothesis of chromatin-encoded memory, as with other experimental systems in eukaryotes. Furthermore, these advances unify multiple properties of vernalization, not only the winter memory. Similarly, in the perennial ssp. , recent integration of molecular with mathematical and ecological approaches unifies chromatin features with the all-year-round memory of seasonal temperature. We develop the concept of FLC season-meter to combine existing information from the contrasting annual/perennial and experimental/theoretical sectors into a transitional framework. We highlight simplicity, high conservation, and discrete differences across extreme life histories in crucifers.
许多植物物种在开花前会越冬。通过一个称为春化作用的过程，向开花的转变与季节转变同步，以响应冬季的长期寒冷。具有不同生活史的十字花科物种中，多个有充分记录的春化特性源自对开花基因中心抑制因子（）的环境调控。在高表达期间开花被阻止，而在低表达期间得以开花。的抑制作用持续到冬季结束并与春季重合；这种异时性方面被称为“冬季记忆”。在一年生植物中，冬季记忆长期以来一直与高度保守的组蛋白修饰因子多梳蛋白和三胸蛋白相关，它们在转录中具有拮抗作用。然而，在确定基因座内动态、异质的组蛋白修饰如何产生最终转录输出方面存在实验局限性。最近关于基因表达和产生双稳态的组蛋白修饰中细胞间变异性的理论思考，为染色质编码记忆的假说提供了支持，就像真核生物中的其他实验系统一样。此外，这些进展不仅统一了春化作用的多个特性，还包括冬季记忆。同样，在多年生植物的亚种中，最近分子方法与数学和生态方法的整合将染色质特征与全年的季节温度记忆统一起来。我们提出了FLC季节计的概念，将来自一年生/多年生植物以及实验/理论领域的现有信息整合到一个过渡框架中。我们强调了十字花科植物极端生活史中的简单性、高度保守性和离散差异。
