隐花色素(CRY)是调节植物光反应的蓝光受体。CRY在黑暗中以无活性的单体形式存在, 吸收光子后构象变化并发生寡聚化, 同时改变了其与互作蛋白间的亲和力, 进而调控光反应蛋白的转录或稳定性以调节植物的生长发育。最近的一项研究发现了CRY2的一个精巧作用机制, CRY不仅可被蓝光“激活”, 还可被黑暗信号“激活”, 从而构建起光信号和暗信号依赖的光受体信号转导更节能的模式。他们发现CRY2即便在黑暗中也能抑制根尖分生组织中的细胞分裂, 调控根的伸长, 并控制大量基因的表达。FL1和FL3与细胞分裂基因的染色质结合以促进其转录。需要说明的是, 只有黑暗中的CRY2单体可与FL1/FL3相互作用, 从而抑制后者促进根伸长的功能, 蓝光则解除该抑制作用。这一发现重塑了人们对光受体的认识, 为理解植物感知和响应不同信号以调节生长和适应性提供了全新的视角, 对深入理解基因的功能极具启发意义。

Cryptochromes (CRYs) are blue light receptors that regulate various plant responses. CRYs exist in the dark as an inactive monomer, which absorbs photons and undergo conformational changes and oligomerization. Light alters the affinity between CRYs and interacting proteins, thereby regulating the transcription or stability of photoresponsive proteins to modulate plant growth and development. A recent study has discovered a sophisticated mechanism of CRY2 function, which is not only ‘activated’ by blue light but also by dark signals, thus constructing a more energy-efficient mode of light and dark signal dependent photoreceptor signaling. The authors found that CRY2 can inhibit cell division in root meristematic tissue even in the dark, regulate root elongation and growth, and control the expression of a large number of genes. FL1 and FL3 bind to the chromatin of cell division genes to promote their transcription. It is interesting that only the CRY2 monomer in the dark interacts with FL1/FL3, thereby inhibiting FL1/FL3 to promote root elongation, while blue light releases this inhibitory effect. This discovery reshapes people’s understanding of light receptors, and provides a new perspective for understanding plant perception and response to different signals to regulate growth and adaptability. Moreover, it is highly enlightening for a deeper understanding of sophisticated gene regulation.