CRISPR/Cas9-mediated functional characterization identifies CmPHR4 as a key regulator of genome-wide blue light transcriptional responses in Cyanidioschyzon merolae
Recent development of the CZON-cutter CRISPR/Cas9 platform has greatly expanded the genetic toolkit available for C. merolae, enabling efficient targeted genome editing and functional analyses (Tanaka et al., 2021). Building on these advances, we applied CRISPR/Cas9-mediated gene disruption to investigate the biological function of CmPHR4. By combining targeted gene disruption with comparative transcriptome analysis under blue- and red-light conditions, we examined whether CmPHR4 is required for establishing the transcriptional response to light. This study provides the first direct genetic evidence supporting the predicted role of CmPHR4 in blue-light-responsive transcription and functionally connects comparative phylogenetic inference with genome-wide light-regulated gene expression.