EVALUATION OF ARTHROSPIRA (SPIRULINA) PLATENSIS PRODUCTION TRAIT USING CPCHID OPERON

Arthrospira (Spirulina) platensis is one of the most cultivated commercial microalgae. Many genotypes of A. platensis have been identified, while not all are suited for economic exploitation because of low productivity or poor vitality. The cpcHID (C-phycocyanin rod linker polypeptide H, I and D) operon encodes the phycobilisome linker peptides involved in the photosynthesis, and may directly correlate to the production trait. Here, ten strains of A. platensis with known production traits from traditional procedure were selected and characterized by cpcHID sequences. With the help of phylogenic analyses, three commercially cultivated strains with high growth yields were in evolutionarily close relationship forming a single cluster, while others with varying low growth yields formed the other cluster. Simultaneously, eight market products were also classified into the cluster with high growth yield. We thus gave the conclusion that production trait from traditional procedure is consistent with the cluster analysis of cpcHID sequence. Furthermore, the cluster-specific residues of CpcHID are revealed, and these residues may involve in the interaction with allophycocyanin or other functions. CpcD structure is predicted and modeled on the allophycocyanin-linker complex, showing the direct interaction between cluster- specific residues and chromophores. In comparison with normal tedious, time and labor-consuming procedure for evaluating the production trait, cluster analysis based on cpcHID sequences is undoubtedly a reasonable way to carry out the high throughout evaluation of this trait and discover new strains for mass production.