Comprehensive analysis of phycobilisome linker proteins in Neopyropia yezoensis: classification, structure, evolution...

Linker proteins are essential components of phycobilisome (PBS), playing critical roles in phycobilisome assembly, energy transfer, and structural stability. However, these proteins remain poorly characterized in the economically important red macroalga Neopyropia yezoensis.

In this study, we identified 24 PBS linker proteins in Ny. yezoensis and systematically investigated their physicochemical properties, structural features, chromosomal localizations, cis-acting elements, evolutionary relationships, and functional roles. These PBS linker proteins were classified into four groups (L_R, L_RC, L_C, and L_CM), with the majority encoded by nuclear genes. Notably, the number of genes within the L_R group has markedly increased in Ny. yezoensis, which may have contributed to the species' adaptation to diverse light environments. Expression analysis revealed that PBS linker genes exhibited distinct stage-specific expression patterns, with many highly expressed during the sporophyte stage, suggesting their crucial roles in adapting to the distinct environmental conditions associated with the two life-history stages of Ny. yezoensis. Furthermore, we found that the expression levels of PBS linker genes were correlated with nitrogen availability, indicating that these PBS linker proteins may regulate phycobilisome assembly in response to nitrogen fluctuations.

This study provides the first comprehensive analysis of PBS linker proteins in Ny. yezoensis. Our findings offer valuable insights into the evolution and function of PBS linker proteins and advance our understanding of the adaptation mechanisms of Ny. yezoensis to complex and dynamic environments.