Wang Fanyue, Chen Min
School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia.
Microorganisms. 2022 Aug 3;10(8):1562. doi: 10.3390/microorganisms10081562.
Chromatic acclimation (CA) is a widespread mechanism for optimizing the composition of phycobiliprotein complexes to maximize the cyanobacterial light capture efficiency. There are seven CA types, CA1-CA7, classified according to various photoregulatory pathways. Here, we use sequence analyses and bioinformatics to predict the presence of CA types according to three GAF (cGMP phosphodiesterase/adenylyl cyclase/FhlA)-containing photoreceptors, CcaS (cyanobacterial chromatic acclimation sensor), RcaE (regulator of chromatic adaptation), and RfpA (regulator for far-red photoacclimation). These photoreceptors were classified into three different phylogenetic groups leading different CA types in a diverse range of cyanobacteria. Combining with genomic information of phycobilisome compositions, the CA capabilities of various cyanobacteria were conjectured. Screening 65 accessible cyanobacterial genomes, we defined 19 cyanobacteria that have the capability to perform far-red light photoacclimation (FaRLiP) under the control of RfpA. Forty out of sixty-five cyanobacteria have the capability to perform green/red light photoacclimation, although they use different photoreceptors (RcaE and/or CcaS) and photoregulatory pathways. The reversible response of photoreceptors in CA regulation pathways trigged by changed light conditions reflects the flexibility of photoregulatory mechanisms in cyanobacteria and the putative independent evolutionary origin of photoacclimation types.
色素适应（CA）是一种广泛存在的机制，用于优化藻胆蛋白复合物的组成，以最大限度地提高蓝藻的光捕获效率。根据不同的光调节途径，有七种CA类型，即CA1 - CA7。在这里，我们使用序列分析和生物信息学方法，根据三种含GAF（cGMP磷酸二酯酶/腺苷酸环化酶/FhlA）的光感受器，即CcaS（蓝藻色素适应传感器）、RcaE（色素适应调节因子）和RfpA（远红光光适应调节因子），来预测CA类型的存在。这些光感受器被分为三个不同的系统发育组，在多种蓝藻中导致不同的CA类型。结合藻胆体组成的基因组信息，推测了各种蓝藻的CA能力。通过筛选65个可获取的蓝藻基因组，我们确定了19种蓝藻能够在RfpA的控制下进行远红光光适应（FaRLiP）。在65种蓝藻中，有40种有能力进行绿/红光光适应，尽管它们使用不同的光感受器（RcaE和/或CcaS）和光调节途径。由光照条件变化引发的CA调节途径中光感受器的可逆反应，反映了蓝藻光调节机制的灵活性以及光适应类型可能的独立进化起源。
