The Antarctic sea ice alga Chlamydomonas sp. ICE-L provides insights into adaptive patterns of chloroplast evolution.
BMC Plant Biol
; 18(1): 53, 2018 Apr 03.
Article
em En
| MEDLINE
| ID: mdl-29614974
ABSTRACT
BACKGROUND:
The ice alga Chlamydomonas sp. ICE-L is the main contributor to primary productivity in Antarctic sea ice ecosystems and is well adapted to the extremely harsh environment. However, the adaptive mechanism of Chlamydomonas sp. ICE-L to sea-ice environment remains unclear. To study the adaptive strategies in Chlamydomonas sp. ICE-L, we investigated the molecular evolution of chloroplast photosynthetic genes that are essential for the accumulation of carbohydrate and energy living in Antarctic sea ice.RESULTS:
The 60 chloroplast protein-coding genes of Chlamydomonas sp. ICE-L were obtained, and the branch-site test detected significant signatures of positive selection on atpB, psaB, and rbcL genes in Chlamydomonas sp. ICE-L associated with the photosynthetic machinery. These positively selected genes were further identified as being under convergent evolution between Chlamydomonas sp. ICE-L and the halotolerant alga Dunaliella salina.CONCLUSIONS:
Our study provides evidence that the phototrophic component of Chlamydomonas sp. ICE-L exhibits adaptive evolution under extreme environment. The positive Darwinian selection operates on the chloroplast protein-coding genes of Antarctic ice algae adapted to extreme environment following functional-specific and lineages-specific patterns. In addition, three positively selected genes with convergent substitutions in Chlamydomonas sp. ICE-L were identified, and the adaptive modifications in these genes were in functionally important regions of the proteins. Our study provides a foundation for future experiments on the biochemical and physiological impacts of photosynthetic genes in green algae.Palavras-chave
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Chlamydomonas
/
Cloroplastos
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article