Biological nitrogen fixation by alternative nitrogenases in boreal cyanolichens: importance of molybdenum availability and implications for current biological nitrogen fixation estimates
Citations Over TimeTop 10% of 2016 papers
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.
Related Papers
- → Lichen fungi have low cyanobiont selectivity in maritime Antarctica(2003)111 cited
- → Identification and study of growth and nitrogenase activity of nitrogen fixing cyanobacteria from tropical soil(1992)9 cited
- → Effect of some photosynthesis‐inhibiting herbicides on growth and nitrogenase activity of a new isolate of cyanobacteria, Nostoc G3(1988)9 cited
- → O2‐induced inactivation of nitrogenase as a mechanism for the toxic action of Cd2+ on Nostoc UAM 208(1994)9 cited
- → Identification of Cyanobacterial Toxins from Lichen Thalli(2023)