Cyanobacteriochromes from Gloeobacterales Provide New Insight into the Diversification of Cyanobacterial Photoreceptors

•Cyanobacteriochromes (CBCRs) are photoreceptors related to phytochromes.•CBCRs from early-branching cyanobacteria identify early-branching CBCR lineages.•Early-branching CBCRs integrate light and pH sensing.•Early-branching cyanobacteria harbor late-evolving CBCRs.•CBCR signaling systems appeared early in cyanobacterial evolution.