TY - JOUR
T1 - Trichodesmium physiological ecology and phosphate reduction in the western tropical South Pacific
AU - Frischkorn, Kyle R.
AU - Krupke, Andreas
AU - Guieu, Cécile
AU - Louis, Justine
AU - Rouco, Mónica
AU - Salazar Estrada, Andrés E.
AU - Van Mooy, Benjamin A.S.
AU - Dyhrman, Sonya T.
N1 - Funding Information:
Acknowledgements. This is a contribution to the OUTPACE (Oligotrophy to UlTra-oligotrophy PACific Experiment) project, which was funded by the French national research agency (ANR-14-CE01-0007-01), the LEFE-CyBER program (CNRS-8 INSU), the GOPS program (IRD) and the CNES (BC T23, ZBC 4500048836). The authors thank Thierry Moutin and Sophie Bonnet for leading the OUTPACE expedition and for the invitation to participate. The authors also thank the OUTPACE science party and the captain and crew of the RV L’Atalante for their assistance and camaraderie while underway. Special thanks to Andrea Caputo and Marcus Stenegren of Stockholm University for assistance while at sea. The authors also acknowledge the Carbonate cluster of the National Center for Genome Analysis Support, and Carrie Ganote in particular, for bioinformatics assistance. Grants from the National Science Foundation to STD (OCE-1332912) and BASVM (OCE-1536346 and OCE-1332898) supported this research. KRF is partially supported by a National Science Foundation Graduate Research Fellowship (DGE-16-44869). This research was also funded by the Simons Foundation’s Simons Collaboration on Ocean Processes and Ecology (SCOPE) (SCOPE award ID 329108 to STD and BVM) and is a contribution of SCOPE.
Publisher Copyright:
© Author(s) 2018.
PY - 2018/10/2
Y1 - 2018/10/2
N2 - N2 fixation by the genus Trichodesmium is predicted to support a large proportion of the primary productivity across the oligotrophic oceans, regions that are considered among the largest biomes on Earth. Many of these environments remain poorly sampled, limiting our understanding of Trichodesmium physiological ecology in these critical oligotrophic regions. Trichodesmium colonies, communities that consist of the Trichodesmium host and their associated microbiome, were collected across the oligotrophic western tropical South Pacific (WTSP). These samples were used to assess host clade distribution, host and microbiome metabolic potential, and functional gene expression, with a focus on identifying Trichodesmium physiological ecology in this region. Genes sets related to phosphorus, iron, and phosphorus-iron co-limitation were dynamically expressed across the WTSP transect, suggestive of the importance of these resources in driving Trichodesmium physiological ecology in this region. A gene cassette for phosphonate biosynthesis was detected in Trichodesmium, the expression of which co-varied with the abundance of Trichodesmium Clade III, which was unusually abundant relative to Clade I in this environment. Coincident with the expression of the gene cassette, phosphate reduction to phosphite and low-molecular-weight phosphonate compounds was measured in Trichodesmium colonies. The expression of genes that enable use of such reduced-phosphorus compounds were also measured in both Trichodesmium and the microbiome. Overall, these results highlight physiological strategies employed by consortia in an undersampled region of the oligotrophic WTSP and reveal the molecular mechanisms underlying previously observed high rates of phosphorus reduction in Trichodesmium colonies.
AB - N2 fixation by the genus Trichodesmium is predicted to support a large proportion of the primary productivity across the oligotrophic oceans, regions that are considered among the largest biomes on Earth. Many of these environments remain poorly sampled, limiting our understanding of Trichodesmium physiological ecology in these critical oligotrophic regions. Trichodesmium colonies, communities that consist of the Trichodesmium host and their associated microbiome, were collected across the oligotrophic western tropical South Pacific (WTSP). These samples were used to assess host clade distribution, host and microbiome metabolic potential, and functional gene expression, with a focus on identifying Trichodesmium physiological ecology in this region. Genes sets related to phosphorus, iron, and phosphorus-iron co-limitation were dynamically expressed across the WTSP transect, suggestive of the importance of these resources in driving Trichodesmium physiological ecology in this region. A gene cassette for phosphonate biosynthesis was detected in Trichodesmium, the expression of which co-varied with the abundance of Trichodesmium Clade III, which was unusually abundant relative to Clade I in this environment. Coincident with the expression of the gene cassette, phosphate reduction to phosphite and low-molecular-weight phosphonate compounds was measured in Trichodesmium colonies. The expression of genes that enable use of such reduced-phosphorus compounds were also measured in both Trichodesmium and the microbiome. Overall, these results highlight physiological strategies employed by consortia in an undersampled region of the oligotrophic WTSP and reveal the molecular mechanisms underlying previously observed high rates of phosphorus reduction in Trichodesmium colonies.
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U2 - 10.5194/bg-15-5761-2018
DO - 10.5194/bg-15-5761-2018
M3 - Article
AN - SCOPUS:85054328039
SN - 1726-4170
VL - 15
SP - 5761
EP - 5778
JO - Biogeosciences
JF - Biogeosciences
IS - 19
ER -