Department of Molecular and Cellular Biology, University of California, Davis, California 95616.
Plant Physiol. 2021 Oct 5;187(2):632-645. doi: 10.1093/plphys/kiab240.
Cyanobacteriochromes (CBCRs) are spectrally diverse photosensors from cyanobacteria distantly related to phytochromes that exploit photoisomerization of linear tetrapyrrole (bilin) chromophores to regulate associated signaling output domains. Unlike phytochromes, a single CBCR domain is sufficient for photoperception. CBCR domains that regulate the production or degradation of cyclic nucleotide second messengers are becoming increasingly well characterized. Cyclic di-guanosine monophosphate (c-di-GMP) is a widespread small-molecule regulator of bacterial motility, developmental transitions, and biofilm formation whose biosynthesis is regulated by CBCRs coupled to GGDEF (diguanylate cyclase) output domains. In this study, we compare the properties of diverse CBCR-GGDEF proteins with those of synthetic CBCR-GGDEF chimeras. Our investigation shows that natural diversity generates promising candidates for robust, broad spectrum optogenetic applications in live cells. Since light quality is constantly changing during plant development as upper leaves begin to shade lower leaves-affecting elongation growth, initiation of flowering, and responses to pathogens, these studies presage application of CBCR-GGDEF sensors to regulate orthogonal, c-di-GMP-regulated circuits in agronomically important plants for robust mitigation of such deleterious responses under natural growing conditions in the field.
蓝藻细菌视紫红质（CBCRs）是与植物色素远缘相关的、光谱多样化的光传感器，它们利用线性四吡咯（bilin）发色团的光异构化来调节相关的信号输出结构域。与植物色素不同，单个 CBCR 结构域就足以进行光感知。越来越多的研究对调节环核苷酸第二信使产生或降解的 CBCR 结构域进行了深入的研究。环二鸟苷酸（c-di-GMP）是一种广泛存在的小分子调节剂，可调节细菌的运动性、发育转变和生物膜形成，其生物合成受与 GGDEF（双鸟苷酸环化酶）输出结构域偶联的 CBCRs 调节。在这项研究中，我们比较了不同的 CBCR-GGDEF 蛋白与合成的 CBCR-GGDEF 嵌合体的特性。我们的研究表明，天然多样性为在活细胞中进行稳健、广谱的光遗传学应用提供了有前景的候选物。由于在植物发育过程中，光质会不断变化，因为上部叶片开始遮蔽下部叶片，从而影响伸长生长、开花的开始和对病原体的反应，因此这些研究预示着将 CBCR-GGDEF 传感器应用于调节农业上重要的植物中正交的、c-di-GMP 调节的回路，以在田间自然生长条件下稳健地减轻这种有害反应。
