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General Marine Environmental Science
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The Evolution of Photosynthesis Gene Clusters in Plasmids P-GS-08-S Yanting Liu* , State Key Laboratory of Marine Environmental Sciences Qiang Zheng, State Key Laboratory of Marine Environmental Sciences Nianzhi Jiao, State Key Laboratory of Marine Environmental Sciences Presenter Email: Yantingl0702@gmail.com |
Aerobic Anoxygenic Photoheterotrophic Bacteria (AAPB) play a significant role in the evolutionary history of photosynthesis. A wealth of evidence indicates that the highly conserved photosynthetic gene clusters (PGCs) of AAPB could be transferred between species, genera and even phyla. The Roseobacter clade is one of the major subgroups of AAPB and has a patchy distribution of photosynthetic species. To explore the likely role of plasmids in the transfer of PGCs, we analyzed the PGCs carried by plasmids (pPGCs) in 13 Roseobacter members, as well as their phylogenetically related strains that contain PGCs in chromosomes (cPGCs). The phylogenetic analyses suggested that pPGCs have two distinct evolutionary origins. Additionally, high sequence similarities were revealed between pPGCs and cPGCs contained by distantly related strains, indicating that PGCs may be transferred between chromosomes and plasmids and between these bacterial strains. A comparison of PGC structures implicated that multiple recombination events might happen between chromosomes and plasmids during the evolution of PGCs. Analyses of the relative synonymous codon usage (RSCU) further indicated that the plasmids carrying PGCs may be redefined as bacterial chromids, suggesting they are stable in bacterial cells and PGCs carried by them may be consistently expressed. |
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