Identification, characterization and expression analysis of the CDPK family in kelp Saccharina japonica

The identification and characterization of SjCDPKs, along with comparative analyses across brown algae, diatoms, and plants, reveal a unique evolutionary trajectory tailored to the ecological niche of brown algae. Expression analysis demonstrates their involvement in gametophyte and sporophyte development, as well as responses to light, copper stress, and pathogen challenges. The different subcellular compartmentalization of SjCDPK4 and SjCDPK5 suggests their distinct functional specializations. These systematic analyses provide insights into the evolution of brown algal CDPKs and are valuable for functional identification of SjCDPKs.