Plants exhibit an enormous phenotypic plasticity to adjust to changing environmental conditions. For this purpose, they have evolved mechanisms to detect and measure biotic and abiotic factors in their surroundings. Phytochrome B exhibits a dual function, since it serves as a photoreceptor for red and far-red light as well as a thermosensor. In 1999, it was first reported that phytochromes not only translocate into the nucleus, but also form subnuclear foci upon irradiation by red light. It took more than 10 years until these phytochrome speckles received their name: These foci were coined photobodies to describe unique phytochrome-containing subnuclear domains that are regulated by light. Since their initial discovery, there has been much speculation about the significance and function of photobodies. Their presumed roles range from pure experimental artifacts to waste deposits or signaling hubs. In this review, we summarize the newest findings about the meaning of phyB photobodies for light and temperature signaling. Recent studies have established that phyB photobodies are formed by liquid-liquid phase separation via multivalent interactions and that they provide diverse functions as biochemical hotspots to regulate gene expression on multiple levels.

中文翻译：

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光敏色素 B 光体内部发生了什么？

植物表现出巨大的表型可塑性来适应不断变化的环境条件。为此，它们进化出了检测和测量周围生物和非生物因素的机制。光敏色素 B 具有双重功能，因为它充当红光和远红光的光感受器以及热传感器。 1999年，首次报道光敏色素不仅易位到细胞核中，而且在红光照射下形成亚核病灶。这些光敏色素斑点花了十多年的时间才得到了它们的名字：这些焦点被创造为光体，用来描述受光调节的独特的含有光敏色素的亚核域。自从最初发现以来，人们对光体的重要性和功能有很多猜测。它们的假定作用范围从纯粹的实验制品到废物沉积物或信号中心。在这篇综述中，我们总结了有关 phyB 光体对光和温度信号传导意义的最新发现。最近的研究表明，phyB 光体是通过多价相互作用通过液-液相分离形成的，并且它们作为生化热点提供多种功能，以在多个水平上调节基因表达。