biogeography of photosynthetic light-harvesting genes in marine phytoplankton生物地理学在海洋浮游植物光合聚光的基因.pdf

Biogeography of Photosynthetic Light-Harvesting Genes in Marine Phytoplankton 1,2 2 2 Thomas S. Bibby , Yinan Zhang , Min Chen * 1 School of Ocean and Earth Sciences, National Oceanography Centre, Southampton, United Kingdom, 2 School of Biological Sciences, University of Sydney, Sydney, New South Wales, Australia Abstract Background: Photosynthetic light-harvesting proteins are the mechanism by which energy enters the marine ecosystem. The dominant prokaryotic photoautotrophs are the cyanobacterial genera Prochlorococcus and Synechococcus that are defined by two distinct light-harvesting systems, chlorophyll-bound protein complexes or phycobilin-bound protein complexes, respectively. Here, we use the Global Ocean Sampling (GOS) Project as a unique and powerful tool to analyze the environmental diversity of photosynthetic light-harvesting genes in relation to available metadata including geographical location and physical and chemical environmental parameters. Methods: All light-harvesting gene fragments and their metadata were obtained from the GOS database, aligned using ClustalX and classified phylogenetically. Each sequence has a name indicative of its geographic location; subsequent biogeographical analysis was performed by correlating light-harvesting gene budgets for each GOS station with surface chlorophyll concentration. Conclusion/Significance: Using the GOS data, we have mapped the biogeography of light-harvesting genes in marine cyanobacteria on ocean-basin scales and show that an environmental gradient exists in which chlorophyll concentration is correlated to diversity of light-harvesting systems. Three functionally distinct types of light-h