BACKGROUND: Nitrogen is an essential nutrient in plant growth. The ability of a plant to supply all or part of its requirements from biological nitrogen fixation (BNF) thanks to interactions with endosymbiotic, associative and endophytic symbionts, confers a great competitive advantage over non-nitrogen-fixing plants. SCOPE: Because BNF in legumes is well documented, this review focuses on BNF in non-legume plants. Despite the phylogenic and ecological diversity among diazotrophic bacteria and their hosts, tightly regulated communication is always necessary between the microorganisms and the host plant to achieve a successful interaction. Ongoing research efforts to improve knowledge of the molecular mechanisms underlying these original relationships and some common strategies leading to a successful relationship between the nitrogen-fixing microorganisms and their hosts are presented. CONCLUSIONS: Understanding the molecular mechanism of BNF outside the legume-rhizobium symbiosis could have important agronomic implications and enable the use of N-fertilizers to be reduced or even avoided. Indeed, in the short term, improved understanding could lead to more sustainable exploitation of the biodiversity of nitrogen-fixing organisms and, in the longer term, to the transfer of endosymbiotic nitrogen-fixation capacities to major non-legume crops.
BACKGROUND:Nitrogen is an essential nutrient in plant growth. The ability of a plant to supply all or part of its requirements from biological nitrogen fixation (BNF) thanks to interactions with endosymbiotic, associative and endophytic symbionts, confers a great competitive advantage over non-nitrogen-fixing plants. SCOPE: Because BNF in legumes is well documented, this review focuses on BNF in non-legume plants. Despite the phylogenic and ecological diversity among diazotrophic bacteria and their hosts, tightly regulated communication is always necessary between the microorganisms and the host plant to achieve a successful interaction. Ongoing research efforts to improve knowledge of the molecular mechanisms underlying these original relationships and some common strategies leading to a successful relationship between the nitrogen-fixing microorganisms and their hosts are presented. CONCLUSIONS: Understanding the molecular mechanism of BNF outside the legume-rhizobium symbiosis could have important agronomic implications and enable the use of N-fertilizers to be reduced or even avoided. Indeed, in the short term, improved understanding could lead to more sustainable exploitation of the biodiversity of nitrogen-fixing organisms and, in the longer term, to the transfer of endosymbiotic nitrogen-fixation capacities to major non-legume crops.
Authors: Kenneth J Sytsma; Jeffery Morawetz; J Chris Pires; Molly Nepokroeff; Elena Conti; Michelle Zjhra; Jocelyn C Hall; Mark W Chase Journal: Am J Bot Date: 2002-09 Impact factor: 3.844
Authors: Eduardo Balsanelli; Rodrigo V Serrato; Valter A de Baura; Guilherme Sassaki; Marshall G Yates; Liu Un Rigo; Fábio O Pedrosa; Emanuel M de Souza; Rose A Monteiro Journal: Environ Microbiol Date: 2010-03-07 Impact factor: 5.491
Authors: A M Berry; O T Harriott; R A Moreau; S F Osman; D R Benson; A D Jones Journal: Proc Natl Acad Sci U S A Date: 1993-07-01 Impact factor: 11.205