Use este identificador para citar ou linkar para este item: http://repositorio.ufla.br/jspui/handle/1/28952
Título : Symbiotic nitrogen-fixing bacterial populations trapped from soils under agroforestry systems in the Western Amazon
Autor: Jaramillo, Paula Marcela Duque
Guimarães, Amanda Azarias
Florentino, Ligiane Aparecida
Silva, Karina Barroso
Nóbrega, Rafaela Simão Abrahão
Moreira, Fatima Maria de Souza
Palavras-chave: Legume-nodulating bacteria
Nitrogen fertilization
Nitrogen-fixing bacteria
Symbiotic promiscuity
Chlorophyll content
Bactérias nodulantes de leguminosas
Adubação nitrogenada
Bactérias fixadoras de nitrogênio
Promiscuidade simbiótica
Conteúdo de clorofila
Publicador: Escola Superior de Agricultura "Luiz de Queiroz"
Data da publicação: Nov-2013
Referência: JARAMILLO, P. M. D. et al. Symbiotic nitrogen-fixing bacterial populations trapped from soils under agroforestry systems in the Western Amazon. Scientia Agricola, Piracicaba, v. 70, n. 6, p. 397-404, Nov./Dec. 2013.
Abstract: Cowpea (Vigna unguiculata) is an important grain-producing legume that can forego nitrogen fertilization by establishing an efficient symbiosis with nitrogen-fixing bacteria. Although inoculating strains have already been selected for this species, little is known about the genotypic and symbiotic diversity of native rhizobia. Recently, Bradyrhizobium has been shown to be the genus most frequently trapped by cowpea in agricultural soils of the Amazon region. We investigated the genetic and symbiotic diversity of 148 bacterial strains with different phenotypic and cultural properties isolated from the nodules of the trap species cowpea, which was inoculated with samples from soils under agroforestry systems from the western Amazon. Sixty non-nodulating strains indicated a high frequency of endophytic strains in the nodules. The 88 authenticated strains had varying symbiotic efficiency. The SPAD (Soil Plant Analysis Development) index (indirect measurement of chlorophyll content) was more efficient at evaluating the contribution of symbiotic N2-fixation than shoot dry matter under axenic conditions. Cowpea-nodulating bacteria exhibited a high level of genetic diversity, with 68 genotypes identified by BOX-PCR. Sequencing of the 16S rRNA gene showed a predominance of the genus Bradyrhizobium, which accounted for 70 % of all strains sequenced. Other genera identified were Rhizobium, Ochrobactrum, Paenibacillus, Bosea, Bacillus, Enterobacter, and Stenotrophomonas. These results support the promiscuity of cowpea and demonstrate the high genetic and symbiotic diversity of rhizobia in soils under agroforestry systems, with some strains exhibiting potential for use as inoculants. The predominance of Bradyrhizobium in land uses with different plant communities and soil characteristics reflects the adaptation of this genus to the Amazon region.
URI: http://repositorio.ufla.br/jspui/handle/1/28952
Idioma: en_US
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