Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland.
Curr Top Dev Biol. 2010;91:29-66. doi: 10.1016/S0070-2153(10)91002-8.
Plants are sessile and photo-autotrophic; their entire life cycle is thus strongly influenced by the ever-changing light environment. In order to sense and respond to those fluctuating conditions higher plants possess several families of photoreceptors that can monitor light from UV-B to the near infrared (far-red). The molecular nature of UV-B sensors remains unknown, red (R) and far-red (FR) light is sensed by the phytochromes (phyA-phyE in Arabidopsis) while three classes of UV-A/blue photoreceptors have been identified: cryptochromes, phototropins, and members of the Zeitlupe family (cry1, cry2, phot1, phot2, ZTL, FKF1, and LKP2 in Arabidopsis). Functional specialization within photoreceptor families gave rise to members optimized for a wide range of light intensities. Genetic and photobiological studies performed in Arabidopsis have shown that these light sensors mediate numerous adaptive responses (e.g., phototropism and shade avoidance) and developmental transitions (e.g., germination and flowering). Some physiological responses are specifically triggered by a single photoreceptor but in many cases multiple light sensors ensure a coordinated response. Recent studies also provide examples of crosstalk between the responses of Arabidopsis to different external factors, in particular among light, temperature, and pathogens. Although the different photoreceptors are unrelated in structure, in many cases they trigger similar signaling mechanisms including light-regulated protein-protein interactions or light-regulated stability of several transcription factors. The breath and complexity of this topic forced us to concentrate on specific aspects of photomorphogenesis and we point the readers to recent reviews for some aspects of light-mediated signaling (e.g., transition to flowering).
植物是固着生物和自养生物；因此，它们的整个生命周期都受到不断变化的光照环境的强烈影响。为了感知和应对这些不断变化的环境条件，高等植物拥有几类光受体，可以监测从 UV-B 到近红外（远红）的光。UV-B 传感器的分子性质仍然未知，红光（R）和远红光（FR）由光敏色素（拟南芥中的 phyA-phyE）感知，而三类 UV-A/蓝光光受体已被鉴定：隐花色素、光受体和 Zeitlupe 家族成员（拟南芥中的 cry1、cry2、phot1、phot2、ZTL、FKF1 和 LKP2）。光受体家族中的功能特化导致了针对广泛光强度的成员优化。在拟南芥中进行的遗传和光生物学研究表明，这些光传感器介导了许多适应性反应（例如向光性和避荫反应）和发育转变（例如萌发和开花）。一些生理反应是由单个光受体特异性触发的，但在许多情况下，多个光传感器确保了协调的反应。最近的研究还提供了拟南芥对不同外部因素（特别是光、温度和病原体）反应之间串扰的例子。尽管不同的光受体在结构上没有关系，但在许多情况下，它们会触发类似的信号机制，包括光调控的蛋白-蛋白相互作用或几个转录因子的光调控稳定性。这个主题的广度和复杂性迫使我们专注于光形态发生的特定方面，我们为读者指出了一些关于光介导信号转导的方面的最新综述（例如，向开花的转变）。
