This is the first paper of the collaborative grant led by Fay-Wei Li to do a worldwide assessment of the symbiosis between hornworts and nitrogen-fixing cyanobacteria.

What’s so new about a vanadium nitrogenase? The nitrogenase with a vanadium co-factor had only been  reported from free-living bacteria and cyanobacteria associated to boreal lichens. This “alternative” nitrogenase  is thought to be more active at low temperatures (below 14C) and it plays a crucial role in the nitrogen cycle of boreal forests (see papers by J-P Bellenger’s lab).

We found the V-nitrogenase in cyanobacteria associated to two temperate plants (bryophytes): the liverwort Blasia pusilla and the hornwort Phaeoceros carolinianus. Besides, it’s present in the Neotropical hornwort (from Panama) Leiosporoceros dussii. The findings pose a number of questions on the functional significance of the alternative nitrogenase in tropical plants.

Nelson, J.M., D.A. Hauser, J.A. Gudiño, Y.A. Guadalupe*, J.C. Meeks, N. Salazar, J.C. Villarreal, F.-W. Li. 2019. Complete Genomes of Symbiotic Cyanobacteria Clarify the Evolution of Vanadium-Nitrogenase. Genome Biology and Evolution