Diversity of Rhizobia and Importance of Their Interactions with Legume Trees for Feasibility and Sustainability of the Tropical Agrosystems
Emanoel G. Moura,
Cristina S. Carvalho,
Cassia P. C. Bucher,
Juliana L. B. Souza,
Alana C. F. Aguiar,
Altamiro S. L. Ferraz Junior,
Carlos A. Bucher,
Katia P. Coelho
Affiliations
Emanoel G. Moura
Postgraduate Program in Agroecology, Maranhão State University, Lourenço Vieira da Silva Avenue, 1000, Jardim São Cristovão, São Luís 65055-310, MA, Brazil
Cristina S. Carvalho
Postgraduate Program in Agroecology, Maranhão State University, Lourenço Vieira da Silva Avenue, 1000, Jardim São Cristovão, São Luís 65055-310, MA, Brazil
Cassia P. C. Bucher
Department of Soils, Federal Rural University of Rio de Janeiro, BR 465, Km 07, Seropédica 23890-000, RJ, Brazil
Juliana L. B. Souza
Postgraduate Program in Biodiversity and Conservation, Federal University of Maranhão, Portuguese Avenue, 1966, Bacanga, São Luís 65080-805, MA, Brazil
Alana C. F. Aguiar
Biology Department, Federal University of Maranhão, Portuguese Avenue, 1966, Bacanga, São Luís 65080-805, MA, Brazil
Altamiro S. L. Ferraz Junior
Postgraduate Program in Agroecology, Maranhão State University, Lourenço Vieira da Silva Avenue, 1000, Jardim São Cristovão, São Luís 65055-310, MA, Brazil
Carlos A. Bucher
Department of Fitotecnia, Federal Rural University of Rio de Janeiro, BR 465, Km 07, Seropédica 23890-000, RJ, Brazil
Katia P. Coelho
Agricultural Engineering Department/Postgraduate Program in Agroecology, Maranhão State University, Lourenço Vieira da Silva Avenue, 1000, Jardim São Cristovão, São Luís 65055-310, MA, Brazil
Symbiotic biological nitrogen fixation (BNF) is a complex process that involves rhizobia, a diverse group of α and β-proteobacteria bacteria, and legume species. Benefits provided by BNF associated with legume trees in tropical environments include improvements to efficiency of nitrogen (N) use, increase of soil carbon sequestration, stabilization of soil organic matter, decrease of soil penetration resistance, and improvement of soil fertility. All these benefits make BNF a crucial ecosystem service to the sustainability of tropical agriculture. Due to the importance of this ecological process and the high diversity of rhizobia, these bacteria have been extensively characterized worldwide. Currently, over 400 species of rhizobia are known, distributed into seven families. In the humid tropics, Leucaena leucocephala, Acacia mangium, Gliricidia sepium, and Clitoria fairchildiana are four of the most common species used by family farmers to create sustainable agricultural systems. These four legumes perform symbiosis with different groups of rhizobia. Exploring BNF could help to enable sustainable intensification of agriculture in the humid tropics, mainly because it can increase N use efficiency in an environment where N is a limiting factor to plant growth.
