Abstract
We genetically modified the composition of photosynthetic pigments in Synechococcus WH8102 for the analysis of photosystems.
Marine-type cyanobacteria, Synechococcus and Prochlorococcus play crucial roles in the primary production in the ocean. Phylogenetic analyses indicate the close relationship between Synechococcus and Prochlorococcus. Although it is most likely that Prochlorococcus has been derived from Synechococcus, they possess very different photosynthetic light-harvesting systems. Synechococcuss uses phycobilisome like other major cyanobacteria. In contrast, Prochlorococcus uses chlorophyll b and a special chlorophyll-b binding protein for their antenna complexes.
We made Synechococcus transformants to understand the development of Synechococcus photosystem to Prochlorococcus photosystem. We transformed Synechococcus sp. WH8102 with the genes for chlorophyllide a oxygenase from Prochlorothrix, another chlorophyll-b containing cyanobacterium, and for chlorophyll b-binding protein prepared from Prochlorococcus MED4. A small amount of chlorophyll b was detected in the transformants, suggesting that Synechococcus has the ability to synthesize and accumulate chlorophyll b like Prochlorococcus.
