Marine diatom proteorhodopsins and their potential role in coping with low iron availability.

Journal Article

Proteorhodopsins (PR) are retinal-binding membrane proteins that function as light-driven proton pumps to generate energy for metabolism and growth. Recently PR-like genes have been identified in some marine eukaryotic protists, including diatoms, dinoflagellates, haptophytes and cryptophytes. These rhodopsins are homologous to green-light-absorbing, ATP-generating PRs present within bacteria. Here we show that in the oceanic diatom Pseudo-nitzschia granii, PR-like gene and protein expressions increase appreciably under iron limitation. In a survey of available transcriptomes, PR-like genes in diatoms are generally found in isolates from marine habitats where seasonal to chronic growth limitation by the micronutrient iron is prevalent, yet similar biogeographical patterns are not apparent in other phytoplankton taxa. We propose that rhodopsin-based phototrophy could account for a proportion of energy synthesis in marine eukaryotic photoautotrophs, especially when photosynthesis is compromised by low iron availability. This alternative ATP-generating pathway could have significant effects on plankton community structure and global ocean carbon cycling.The ISME Journal advance online publication, 29 May 2015; doi:10.1038/ismej.2015.74.

Full Text

Duke Authors

Cited Authors

  • Marchetti, A; Catlett, D; Hopkinson, BM; Ellis, K; Cassar, N

Published Date

  • May 2015

Published In

PubMed ID

  • 26023874

Pubmed Central ID

  • 26023874

Electronic International Standard Serial Number (EISSN)

  • 1751-7370

International Standard Serial Number (ISSN)

  • 1751-7362

Digital Object Identifier (DOI)

  • 10.1038/ismej.2015.74

Language

  • eng