@article{8b4054429beb4b34a5a867b17692c669,
title = "Biological nitrogen fixation by alternative nitrogenases in boreal cyanolichens: importance of molybdenum availability and implications for current biological nitrogen fixation estimates",
abstract = "Cryptogamic species and their associated cyanobacteria have attracted the attention of biogeochemists because of their critical roles in the nitrogen cycle through symbiotic and asymbiotic biological fixation of nitrogen (BNF). BNF is mediated by the nitrogenase enzyme, which, in its most common form, requires molybdenum at its active site. Molybdenum has been reported as a limiting nutrient for BNF in many ecosystems, including tropical and temperate forests. Recent studies have suggested that alternative nitrogenases, which use vanadium or iron in place of molybdenum at their active site, might play a more prominent role in natural ecosystems than previously recognized. Here, we studied the occurrence of vanadium, the role of molybdenum availability on vanadium acquisition and the contribution of alternative nitrogenases to BNF in the ubiquitous cyanolichen Peltigera aphthosa s.l. We confirmed the use of the alternative vanadium-based nitrogenase in the Nostoc cyanobiont of these lichens and its substantial contribution to BNF in this organism. We also showed that the acquisition of vanadium is strongly regulated by the abundance of molybdenum. These findings show that alternative nitrogenase can no longer be neglected in natural ecosystems, particularly in molybdenum-limited habitats.",
keywords = "Peltigera aphthosa s.l., alternative nitrogenases, biological nitrogen fixation, boreal forest, cyanolichens, molybdenum (Mo), vanadium (V)",
author = "Romain Darnajoux and Xinning Zhang and McRose, {Darcy L.} and Jolanta Miadlikowska and Fran{\c c}ois Lutzoni and Kraepiel, {Anne M.L.} and Bellenger, {Jean Philippe}",
note = "Funding Information: We wish to thank Mikhail Zhurbenko, as well as Anastasya Knorre and Altyna Dutbaeva, both at {\textquoteleft}Stolby{\textquoteright} National Wildlife Nature Reserve (Krasnoyarsk, Siberia, Russia), for the field assistance in Russia; Air Saguenay pilot Jacques B{\'e}rub{\'e} and the team at Lac Margane for the sampling in northern Qu{\'e}bec, Canada, as well as the Soci{\'e}t{\'e} des {\'e}tablissements de plein air du Qu{\'e}bec (SEPAQ) Fjord du Saguenay; and members of the Lutzoni laboratory (Bernie Ball, Emilie Lef{\`e}vre) and the Arnold laboratory (University of Arizona) (A. Elizabeth Arnold and Kayla Arendt) for the field work in Qu{\'e}bec. We also thank Marie-Charlotte Nilsson-Hegethorn and members of her research team for their support in sample collection in Sweden. The sampling of lichen specimens for this project was, in part, performed with the financial support of the National Science Foundation through a Dimensions of Biodiversity award DEB-1046065 to F.L. and a REVSYS award on the genus Peltigera DEB-1025930 to J.M. and F.L. This work was supported by the Canadian Research Chair in terrestrial biogeochemistry (CRC-950-219383), the Natural Sciences and Engineering Research Council of Canada through a Discovery grant (RGPIN-386963-2011) and the Fond Queb{\'e}cois de Recherche, Nature et Technologie through a Nouveau chercheur grant (FRQNT-2014NC-172330). Publisher Copyright: {\textcopyright} 2016 The Authors. New Phytologist {\textcopyright} 2016 New Phytologist Trust",
year = "2017",
month = jan,
day = "1",
doi = "10.1111/nph.14166",
language = "English (US)",
volume = "213",
pages = "680--689",
journal = "New Phytologist",
issn = "0028-646X",
publisher = "Wiley-Blackwell",
number = "2",
}