Green fluorescent protein-like pigments optimize the internal light environment in symbiotic reef building corals
Green fluorescent protein-like pigments optimize the internal light environment in symbiotic reef building corals
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绿色荧光蛋白类色素优化共生造礁珊瑚的内部光环境
DOI：
10.1101/2021.10.05.463211
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Bollati E
中科院分区：
文献类型：
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作者：
Bollati E
与绿色荧光蛋白(GFP)同源的色素被提出用来微调珊瑚内部的光小气候，促进光合性珊瑚共生体(共生科)适应不同珊瑚礁生境和环境条件下的生活。然而，缺乏对珊瑚组织内体内光照条件的直接测量来支持这一结论。在这里，我们量化了组织内光谱光环境中表达GFP样蛋白的珊瑚，这些珊瑚来自非常不同的光环境。我们的重点是：(1)光可转换红色荧光蛋白(PCRFPs)，被认为通过波长转换增强中游生境的光合作用；(2)色素蛋白(CP)，通过光吸收为浅水中的共生体提供光保护。光学显微传感器测量表明，这两个色素组都强烈改变了珊瑚组织内的光环境。从含有二氯三氯甲苯的珊瑚中测得的光谱估计表明，荧光发射可以贡献50%的橙红色光，这些光可用于中生层深处的光合作用共生体。我们进一步表明，与低CP组织相比，漂白过程中浅水珊瑚中粉红色CP的上调导致橙色光减少10-20%。因此，CPS的筛选在减轻漂白过程中珊瑚组织散射和骨骼反射的光增强效应方面具有重要作用。我们的结果首次实验量化了GFP样蛋白在光驯化过程中微调珊瑚光小气候的重要性。
Pigments homologous to the green fluorescent protein (GFP) have been proposed to fine-tune the internal light microclimate of corals, facilitating photoacclimation of photosynthetic coral symbionts (Symbiodiniaceae) to life in different reef habitats and environmental conditions. However, direct measurements of the in vivo light conditions inside the coral tissue supporting this conclusion are lacking. Here, we quantified the intra-tissue spectral light environment of corals expressing GFP-like proteins from widely different light regimes. We focus on:(1) photoconvertible red fluorescent proteins (pcRFPs), thought to enhance photosynthesis in mesophotic habitats via wavelength conversion, and (2) chromoproteins (CPs), which provide photoprotection to the symbionts in shallow water via light absorption. Optical microsensor measurements indicated that both pigment groups strongly alter the coral intra-tissue light environment. Estimates derived from light spectra measured in pcRFP-containing corals showed that fluorescence emission can contribute to> 50% of orange-red light available to the photosynthetic symbionts at mesophotic depths. We further show that upregulation of pink CPs in shallow-water corals during bleaching leads to a reduction of orange light by 10–20% compared to low-CP tissue. Thus, screening by CPs has an important role in mitigating the light-enhancing effect of coral tissue scattering and skeletal reflection during bleaching. Our results provide the first experimental quantification of the importance of GFP-like proteins in fine-tuning the light microclimate of corals during photoacclimation.