Publication Date:
2000-09-08
Description:
The origin and evolution of photosynthesis have long remained enigmatic due to a lack of sequence information of photosynthesis genes across the entire photosynthetic domain. To probe early evolutionary history of photosynthesis, we obtained new sequence information of a number of photosynthesis genes from the green sulfur bacterium Chlorobium tepidum and the green nonsulfur bacterium Chloroflexus aurantiacus. A total of 31 open reading frames that encode enzymes involved in bacteriochlorophyll/porphyrin biosynthesis, carotenoid biosynthesis, and photosynthetic electron transfer were identified in about 100 kilobase pairs of genomic sequence. Phylogenetic analyses of multiple magnesium-tetrapyrrole biosynthesis genes using a combination of distance, maximum parsimony, and maximum likelihood methods indicate that heliobacteria are closest to the last common ancestor of all oxygenic photosynthetic lineages and that green sulfur bacteria and green nonsulfur bacteria are each other's closest relatives. Parsimony and distance analyses further identify purple bacteria as the earliest emerging photosynthetic lineage. These results challenge previous conclusions based on 16S ribosomal RNA and Hsp60/Hsp70 analyses that green nonsulfur bacteria or heliobacteria are the earliest phototrophs. The overall consensus of our phylogenetic analysis, that bacteriochlorophyll biosynthesis evolved before chlorophyll biosynthesis, also argues against the long-held Granick hypothesis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Xiong, J -- Fischer, W M -- Inoue, K -- Nakahara, M -- Bauer, C E -- GM53940/GM/NIGMS NIH HHS/ -- R01 GM053940/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2000 Sep 8;289(5485):1724-30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Indiana University, Bloomington, IN 47405, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10976061" target="_blank"〉PubMed〈/a〉
Keywords:
Bacteria/*genetics/metabolism
;
Bacterial Proteins/genetics
;
Bacteriochlorophylls/biosynthesis/genetics
;
Chlorobi/*genetics/*metabolism
;
Chlorophyll/biosynthesis
;
Cyanobacteria/genetics/metabolism
;
*Evolution, Molecular
;
Genes, Bacterial
;
Molecular Sequence Data
;
Photosynthesis/*genetics
;
Phylogeny
;
Polymerase Chain Reaction
;
Sequence Analysis, DNA
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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