Migration of the plastid genome to the nucleus in a peridinin dinoflagellate.
Dinoflagellate algae are important primary producers and of significant ecological and economic impact because of their ability to form "red tides". They are also models for evolutionary research because of an unparalleled ability to capture photosynthetic organelles (plastids) through endosymbiosis. The nature and extent of the plastid genome in the dominant perdinin-containing dinoflagellates remain, however, two of the most intriguing issues in plastid evolution. The plastid genome in these taxa is reduced to single-gene minicircles encoding an incomplete (until now 15) set of plastid proteins. The location of the remaining photosynthetic genes is unknown. We generated a data set of 6,480 unique expressed sequence tags (ESTs) from the toxic dinoflagellate Alexandrium tamarense (for details, see the Experimental Procedures in the Supplemental Data) to find the missing plastid genes and to understand the impact of endosymbiosis on genome evolution. Here we identify 48 of the non-minicircle-encoded photosynthetic genes in the nuclear genome of A. tamarense, accounting for the majority of the photosystem. Fifteen genes that are always found on the plastid genome of other algae and plants have been transferred to the nucleus in A. tamarense. The plastid-targeted genes have red and green algal origins. These results highlight the unique position of dinoflagellates as the champions of plastid gene transfer to the nucleus among photosynthetic eukaryotes.
Hackett
Jeremiah D
JD
Department of Biological Sciences and Center for Comparative Genomics, The University of Iowa, Iowa City, IA 52242, USA.
Yoon
Hwan Su
HS
Soares
M Bento
MB
Bonaldo
Maria F
MF
Casavant
Thomas L
TL
Scheetz
Todd E
TE
Nosenko
Tetyana
T
Bhattacharya
Debashish
D
D000595:Amino Acid Sequence; D000818:Animals; D001499:Bayes Theorem; D001692:Biological Transport; D002338:Carotenoids; D002467:Cell Nucleus / Q000235:genetics / Q000502:physiology*; D016000:Cluster Analysis; D004141:Dinoflagellida / Q000235:genetics*; D020224:Expressed Sequence Tags; D016678:Genome; D008969:Molecular Sequence Data; D010788:Photosynthesis / Q000235:genetics*; D010802:Phylogeny; D018087:Plastids / Q000235:genetics*; D013559:Symbiosis
C016040:peridinin; D002338:Carotenoids