In the Limelight: Photoreceptors in Cyanobacteria.

Devaki Bhaya

doi:10.1128/mbio.00741-16

Abstract

ABSTRACTCertain cyanobacteria look green if grown in red light and vice versa. This dramatic color change, called complementary chromatic adaptation (CCA), is caused by alterations of the major colored light-harvesting proteins. A major controller of CCA is the cyanobacteriochrome (CBCR) RcaE, a red-green reversible photoreceptor that triggers a complex signal transduction pathway. Now, a new study demonstrates that CCA is also modulated by DpxA, a CBCR that senses yellow and teal (greenish blue) light. DpxA acts to expand the range of wavelengths that can impact CCA, by fine-tuning the process. This dual control of CCA might positively impact the fitness of cells growing in the shade of competing algae or in a water column where light levels and spectral quality change gradually with depth. This discovery adds to the growing number of light-responsive phenomena controlled by multiple CBCRs. Furthermore, the diverse CBCRs which are exclusively found in cyanobacteria have significant biotechnological potential.

Highlights

Certain cyanobacteria look green if grown in red light and vice versa
Group III is comprised of cyanobacteriochromes (CBCRs), which are exclusively found in cyanobacteria
One of the most striking examples of light-regulated control by CBCRs is a phenomenon known as complementary chromatic adaptation (CCA), in which certain cyanobacteria can appear in different colors based on the light in which they are grown (Fig. 1)

Summary

Introduction

Certain cyanobacteria look green if grown in red light and vice versa. This dramatic color change, called complementary chromatic adaptation (CCA), is caused by alterations of the major colored light-harvesting proteins. CBCRs represent an abundant and diverse subfamily that contains bilin-binding PAS-GAF domains. One of the most striking examples of light-regulated control by CBCRs is a phenomenon known as complementary chromatic adaptation (CCA), in which certain cyanobacteria can appear in different colors based on the light in which they are grown (Fig. 1).

Results

Conclusion