RRC ID 58545
著者 Sarai C, Tanifuji G, Nakayama T, Kamikawa R, Takahashi K, Yazaki E, Matsuo E, Miyashita H, Ishida KI, Iwataki M, Inagaki Y.
タイトル Dinoflagellates with relic endosymbiont nuclei as models for elucidating organellogenesis.
ジャーナル Proc Natl Acad Sci U S A
Abstract Nucleomorphs are relic endosymbiont nuclei so far found only in two algal groups, cryptophytes and chlorarachniophytes, which have been studied to model the evolutionary process of integrating an endosymbiont alga into a host-governed plastid (organellogenesis). However, past studies suggest that DNA transfer from the endosymbiont to host nuclei had already ceased in both cryptophytes and chlorarachniophytes, implying that the organellogenesis at the genetic level has been completed in the two systems. Moreover, we have yet to pinpoint the closest free-living relative of the endosymbiotic alga engulfed by the ancestral chlorarachniophyte or cryptophyte, making it difficult to infer how organellogenesis altered the endosymbiont genome. To counter the above issues, we need novel nucleomorph-bearing algae, in which endosymbiont-to-host DNA transfer is on-going and for which endosymbiont/plastid origins can be inferred at a fine taxonomic scale. Here, we report two previously undescribed dinoflagellates, strains MGD and TGD, with green algal endosymbionts enclosing plastids as well as relic nuclei (nucleomorphs). We provide evidence for the presence of DNA in the two nucleomorphs and the transfer of endosymbiont genes to the host (dinoflagellate) genomes. Furthermore, DNA transfer between the host and endosymbiont nuclei was found to be in progress in both the MGD and TGD systems. Phylogenetic analyses successfully resolved the origins of the endosymbionts at the genus level. With the combined evidence, we conclude that the host-endosymbiont integration in MGD/TGD is less advanced than that in cryptophytes/chrorarachniophytes, and propose the two dinoflagellates as models for elucidating organellogenesis.
巻・号 117(10)
ページ 5364-5375
公開日 2020-3-10
DOI 10.1073/pnas.1911884117
PII 1911884117
PMID 32094181
PMC PMC7071878
MeSH Cell Nucleus / genetics Cell Nucleus / physiology Cercozoa / classification Cercozoa / genetics Cercozoa / ultrastructure* Chlorophyta / classification Chlorophyta / physiology Chlorophyta / ultrastructure Cryptophyta / classification Cryptophyta / genetics Cryptophyta / ultrastructure* Dinoflagellida / classification Dinoflagellida / genetics Dinoflagellida / ultrastructure* Evolution, Molecular* Genome, Plastid* Models, Biological Phylogeny Plastids / genetics Plastids / physiology* Symbiosis*
IF 9.412
引用数 0
リソース情報
藻類 NIES-1868