TY - JOUR
T1 - Non-cyanobacterial diazotrophs mediate dinitrogen fixation in biological soil crusts during early crust formation
AU - Pepe-Ranney, Charles
AU - Koechli, Chantal
AU - Potrafka, Ruth
AU - Andam, Cheryl
AU - Eggleston, Erin
AU - Garcia-Pichel, Ferran
AU - Buckley, Daniel H.
N1 - Funding Information:
We thank T Whitman, CHD Williamson, AN Campbell and EK Hall for helpful comments in the preparation of this manuscript. This material is based upon work supported by the Department of Energy Office of Science, Office of Biological and Environmental Research Genomic Science Program under Award Numbers DE-SC0004486 and DE-SC0010558. This project was also supported by Agriculture and Food Research Initiative Competitive Grant no. 2007-35107-18299 from the USDA National Institute of Food and Agriculture. This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness or usefulness of any information, apparatus, product or process disclosed or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process or service by trade name, trademark, manufacturer or otherwise does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
Publisher Copyright:
© 2016 International Society for Microbial Ecology All rights reserved.
PY - 2016/2/1
Y1 - 2016/2/1
N2 - Biological soil crusts (BSCs) are key components of ecosystem productivity in arid lands and they cover a substantial fraction of the terrestrial surface. In particular, BSC N 2 -fixation contributes significantly to the nitrogen (N) budget of arid land ecosystems. In mature crusts, N 2 -fixation is largely attributed to heterocystous cyanobacteria; however, early successional crusts possess few N 2 -fixing cyanobacteria and this suggests that microorganisms other than cyanobacteria mediate N 2 -fixation during the critical early stages of BSC development. DNA stable isotope probing with 15 N 2 revealed that Clostridiaceae and Proteobacteria are the most common microorganisms that assimilate 15 N 2 in early successional crusts. The Clostridiaceae identified are divergent from previously characterized isolates, though N 2 -fixation has previously been observed in this family. The Proteobacteria identified share >98.5% small subunit rRNA gene sequence identity with isolates from genera known to possess diazotrophs (for example, Pseudomonas, Klebsiella, Shigella and Ideonella). The low abundance of these heterotrophic diazotrophs in BSCs may explain why they have not been characterized previously. Diazotrophs have a critical role in BSC formation and characterization of these organisms represents a crucial step towards understanding how anthropogenic change will affect the formation and ecological function of BSCs in arid ecosystems.
AB - Biological soil crusts (BSCs) are key components of ecosystem productivity in arid lands and they cover a substantial fraction of the terrestrial surface. In particular, BSC N 2 -fixation contributes significantly to the nitrogen (N) budget of arid land ecosystems. In mature crusts, N 2 -fixation is largely attributed to heterocystous cyanobacteria; however, early successional crusts possess few N 2 -fixing cyanobacteria and this suggests that microorganisms other than cyanobacteria mediate N 2 -fixation during the critical early stages of BSC development. DNA stable isotope probing with 15 N 2 revealed that Clostridiaceae and Proteobacteria are the most common microorganisms that assimilate 15 N 2 in early successional crusts. The Clostridiaceae identified are divergent from previously characterized isolates, though N 2 -fixation has previously been observed in this family. The Proteobacteria identified share >98.5% small subunit rRNA gene sequence identity with isolates from genera known to possess diazotrophs (for example, Pseudomonas, Klebsiella, Shigella and Ideonella). The low abundance of these heterotrophic diazotrophs in BSCs may explain why they have not been characterized previously. Diazotrophs have a critical role in BSC formation and characterization of these organisms represents a crucial step towards understanding how anthropogenic change will affect the formation and ecological function of BSCs in arid ecosystems.
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U2 - 10.1038/ismej.2015.106
DO - 10.1038/ismej.2015.106
M3 - Article
C2 - 26114889
AN - SCOPUS:84955214852
SN - 1751-7362
VL - 10
SP - 287
EP - 298
JO - ISME Journal
JF - ISME Journal
IS - 2
ER -