Photosynthetic Protein-Based Edible Quality Formation in Various Porphyra dentata Harvests Determined by Label-Free Proteomics Analysis

The influence of harvest time on the photosynthetic protein quality of the red alga Porphyra dentata was determined using label-free proteomics. Of 2716 differentially abundant proteins that were identified in this study, 478 were upregulated and 374 were downregulated. The top enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) pathways were metabolic processes and biosynthetic pathways such as photosynthesis, light harvesting, and carbon fixation in photosynthetic organisms. Nine important photosynthetic proteins were screened. Correlations among their expression levels were contrasted and verified by western blotting. PSII D1 and 44-kDa protein levels increased with later harvest time and increased light exposure. Specific photoprotective protein expression accelerated P. dentata growth and development. Biological processes such as photosynthesis and carbon cycling increased carbohydrate metabolism and decreased the total protein content. The results of the present study provide a scientific basis for the optimization of the culture and harvest of P. dentata.