title: Evolution of the Tetrapyrrole Biosynthetic Pathway in Secondary Algae: Conservation, Redundancy and Replacement.
abstract: Tetrapyrroles such as chlorophyll and heme are indispensable for life because they are involved in energy fixation and consumption, i.e. photosynthesis and oxidative phosphorylation. In eukaryotes, the tetrapyrrole biosynthetic pathway is shaped by past endosymbioses. We investigated the origins and predicted locations of the enzymes of the heme pathway in the chlorarachniophyte Bigelowiella natans, the cryptophyte Guillardia theta, the "green" dinoflagellate Lepidodinium chlorophorum, and three dinoflagellates with diatom endosymbionts ("dinotoms"): Durinskia baltica, Glenodinium foliaceum and Kryptoperidinium foliaceum. Bigelowiella natans appears to contain two separate heme pathways analogous to those found in Euglena gracilis; one is predicted to be mitochondrial-cytosolic, while the second is predicted to be plastid-located. In the remaining algae, only plastid-type tetrapyrrole synthesis is present, with a single remnant of the mitochondrial-cytosolic pathway, a ferrochelatase of G. theta putatively located in the mitochondrion. The green dinoflagellate contains a single pathway composed of mostly rhodophyte-origin enzymes, and the dinotoms hold two heme pathways of apparently plastidal origin. We suggest that heme pathway enzymes in B. natans and L. chlorophorum share a predominantly rhodophytic origin. This implies the ancient presence of a rhodophyte-derived plastid in the chlorarachniophyte alga, analogous to the green dinoflagellate, or an exceptionally massive horizontal gene transfer.
authors.affiliation: Biology Centre, Czech Academy of Sciences, Institute of Parasitology, České Budějovice, Czech Republic.|University of South Bohemia, Faculty of Science, České Budějovice, Czech Republic.
authors.forename: Jaromír
authors.initials: J
authors.lastname: Cihlář
authors.affiliation: Biology Centre, Czech Academy of Sciences, Institute of Parasitology, České Budějovice, Czech Republic.
authors.forename: Zoltán
authors.identifier: http://orcid.org/0000-0002-0820-6359
authors.initials: Z
authors.lastname: Füssy
authors.affiliation: Biology Centre, Czech Academy of Sciences, Institute of Parasitology, České Budějovice, Czech Republic.|University of South Bohemia, Faculty of Science, České Budějovice, Czech Republic.
authors.forename: Aleš
authors.initials: A
authors.lastname: Horák
authors.affiliation: Biology Centre, Czech Academy of Sciences, Institute of Parasitology, České Budějovice, Czech Republic.|University of South Bohemia, Faculty of Science, České Budějovice, Czech Republic.|Institute of Microbiology, Czech Academy of Sciences, Třeboň, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Oborník
mesh_terms: D005075:Biological Evolution; D053898:Biosynthetic Pathways / Q000235:genetics; D044785:Cryptophyta / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D017377:Diatoms / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D004141:Dinoflagellida / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D006418:Heme / Q000378:metabolism; D010802:Phylogeny; D000623:Porphobilinogen Synthase / Q000235:genetics / Q000378:metabolism; D045725:Tetrapyrroles / Q000378:metabolism*
chemical_list: D045725:Tetrapyrroles; D006418:Heme; D000623:Porphobilinogen Synthase