title: Robust biological nitrogen fixation in a model grass-bacterial association.
abstract: Nitrogen-fixing rhizobacteria can promote plant growth; however, it is controversial whether biological nitrogen fixation (BNF) from associative interaction contributes to growth promotion. The roots of Setaria viridis, a model C4 grass, were effectively colonized by bacterial inoculants resulting in a significant enhancement of growth. Nitrogen-13 tracer studies provided direct evidence for tracer uptake by the host plant and incorporation into protein. Indeed, plants showed robust growth under nitrogen-limiting conditions when inoculated with an ammonium-excreting strain of Azospirillum brasilense. (11)C-labeling experiments showed that patterns in central carbon metabolism and resource allocation exhibited by nitrogen-starved plants were largely reversed by bacterial inoculation, such that they resembled plants grown under nitrogen-sufficient conditions. Adoption of S. viridis as a model should promote research into the mechanisms of associative nitrogen fixation with the ultimate goal of greater adoption of BNF for sustainable crop production.
authors: Department of Biochemistry and Molecular Biology, Federal University of Paraná, 81531-980, Curitiba, Brazil.
authors: Vânia C S
authors: VC
authors: Pankievicz
authors: Fernanda P
authors: FP
authors: do Amaral
authors: Karina F D N
authors: KF
authors: Santos
authors: Beverly
authors: B
authors: Agtuca
authors: Youwen
authors: Y
authors: Xu
authors: Michael J
authors: MJ
authors: Schueller
authors: Ana Carolina M
authors: AC
authors: Arisi
authors: Maria B R
authors: MB
authors: Steffens
authors: Emanuel M
authors: EM
authors: de Souza
authors: Fábio O
authors: FO
authors: Pedrosa
authors: Gary
authors: G
authors: Stacey
authors: Richard A
authors: RA
authors: Ferrieri
mesh_terms: D015806:Azospirillum brasilense / Q000502:physiology*; D002250:Carbon Radioisotopes / Q000032:analysis; D060026:Endophytes; D042803:Herbaspirillum / Q000502:physiology*; D008954:Models, Biological; D009584:Nitrogen / Q000378:metabolism*; D009586:Nitrogen Fixation; D018517:Plant Roots / Q000378:metabolism / Q000382:microbiology*; D058441:Rhizosphere; D032983:Setaria Plant / Q000254:growth & development / Q000378:metabolism* / Q000382:microbiology
chemical_list: D002250:Carbon Radioisotopes; D009584:Nitrogen
keywords: Azospirillum brasilense; Herbaspirillum seropedicae; Setaria; endophyte; nitrogen fixation; plant growth promotion; radioisotope; rhizosphere