Symbiotic nitrogen fixation in the fungus gardens of leaf-cutter ants.
Bacteria-mediated acquisition of atmospheric N2 serves as a critical source of nitrogen in terrestrial ecosystems. Here we reveal that symbiotic nitrogen fixation facilitates the cultivation of specialized fungal crops by leaf-cutter ants. By using acetylene reduction and stable isotope experiments, we demonstrated that N2 fixation occurred in the fungus gardens of eight leaf-cutter ant species and, further, that this fixed nitrogen was incorporated into ant biomass. Symbiotic N2-fixing bacteria were consistently isolated from the fungus gardens of 80 leaf-cutter ant colonies collected in Argentina, Costa Rica, and Panama. The discovery of N2 fixation within the leaf-cutter ant-microbe symbiosis reveals a previously unrecognized nitrogen source in neotropical ecosystems.
Pinto-Tomás
Adrián A
AA
Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA.
Anderson
Mark A
MA
Suen
Garret
G
Stevenson
David M
DM
Chu
Fiona S T
FS
Cleland
W Wallace
WW
Weimer
Paul J
PJ
Currie
Cameron R
CR
D000114:Acetylene / Q000378:metabolism; D000818:Animals; D001000:Ants / Q000378:metabolism / Q000382:microbiology / Q000502:physiology*; D001118:Argentina; D003364:Costa Rica; D017753:Ecosystem; D005658:Fungi / Q000254:growth & development / Q000502:physiology*; D007709:Klebsiella / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism; D009586:Nitrogen Fixation; D010084:Oxidation-Reduction; D010176:Panama; D020636:Pantoea / Q000302:isolation & purification / Q000378:metabolism*; D010802:Phylogeny; D018515:Plant Leaves / Q000737:chemistry; D013559:Symbiosis
D009584:Nitrogen; D000114:Acetylene