Bioluminescence in dinoflagellates–diversity, molecular phylogeny and field ecology

摘要: Marine dinoflagellates are an ecologically important group of protists within the plankton, performing key process such as photosynthesis, heterotrophy and toxin production. Some dinoflagellates are also capable of producing bioluminescence and they are the most abundant protists that produce light in the surface waters of the oceans. Thisstudy employed molecular tools to investigate the identity of bioluminescent species, the genetic basis, diversity and functional regulation of bioluminescence, and the distribution of marine bioluminescent dinoflagellate populations.Using “universal” and taxon specific PCR primers designed to amplify the luciferase gene (lcf), the distribution of this gene within dinoflagellates was found to be taxon specific and the first lcf sequences obtained from four genetically distant genera revealed a previously unknown high diversity of this gene. The luciferin binding protein gene (lbp) was detected for the first time in three genera of ecologically important gonyaulacoid dinoflagellates, showing that this understudied gene is common in dinoflagellate bioluminescence systems. Phylogenetic analyses of both lcf and lbp provided new insight on species divergence within the toxic genus Alexandrium and pointed out important pitfalls in using protein coding genes for phylogenetic studies. The lcf PCR primers wereemployed in the first field study using a molecular approach to detect natural populations of bioluminescent dinoflagellates, showing that this approach outperforms optical bioluminescence measurements and that their distribution and composition is intimately tied to hydrographic patterns that create distinct …