Sensibilidade de estirpes de Bradyrhizobium ao glyphosate

Sensitivity of Bradyrhizobium strains to glyphosate

FITOSSANIDADE/PLANT PROTECTION

Sensibilidade de estirpes de Bradyrhizobium ao glyphosate

Sensitivity of Bradyrhizobium strains to glyphosate

Rodrigo Josemar Seminoti Jacques^I; Sérgio de Oliveira Procópio^II; José Barbosa dos Santos^III; Maria Catarina Megumi Kasuya^IV; Antônio Alberto da Silva^V

^IEngenheiro-Agrônomo, Doutor. Departamento de Solos, Universidade Federal de Santa Maria, Avenida Roraima, 1000, 971005-900, Santa Maria, Rio Grande do Sul, Brasil. [e-mail] ^IIEngenheiro-Agrônomo, Doutor. Embrapa Tabuleiros Costeiros, Avenida Beira Mar, 3250, 49025-040, Aracaju, Sergipe, Brasil. [e-mail] ^IIIEngenheiro-Agrônomo, Doutor. Departamento de Agronomia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Rodovia MGT 367, Km 583, 39100-000, Diamantina, Minas Gerais, Brasil. [e-mail] ^IVEngenheira-Agrônoma, Doutora. Departamento de Microbiologia, Universidade Federal de Viçosa, Avenida Peter H. Rolfs, s/n, 36570-000, Viçosa, Minas Gerais. [e-mail]

^VEngenheiro-Agrônomo, Doutor. Departamento de Fitotecnia, Universidade Federal de Viçosa, Avenida Peter H. Rolfs, s/n, 36570-000, Viçosa, Minas Gerais. [e-mail]

RESUMO

A aplicação do glyphosate sobre a soja resistente a este herbicida pode causar prejuízos à simbiose com o rizóbio. O objetivo deste trabalho foi avaliar a sensibilidade ao herbicida glyphosate de três estirpes de Bradyrhizobium recomendadas para a produção de inoculantes de sementes de soja no Brasil. Avaliou-se o efeito das concentrações de 0,0; 5,4; 10,8; 21,6 e 43,2 µg L^-1 do ingrediente ativo do glyphosate [N-(fosfonometil) glicina] no meio YM líquido sobre o crescimento de B. japonicum (estirpe SEMIA 5079) e de B. elkanii (estirpe SEMIA 5019 e estirpe SEMIA 587), por meio de leituras das densidades óticas e geração de curvas de crescimento. As reduções de crescimento na presença da menor concentração do glyphosate foram de 18% para SEMIA 5079, 29% para SEMIA 5019 e de 35% para SEMIA 587, sendo, de modo geral, quanto maior a concentração do herbicida no meio de cultura maior a inibição do crescimen­to. As estirpes apresentaram sensibilidade diferencial somente às concentrações mais baixas do glyphosate; nesse caso, foi possível determinar a seguinte ordem de sensibilidade: SEMIA 587 > SEMIA 5019 > SEMIA 5079. Essa sensibilidade diferencial é dependente da concentração do herbicida, pois na presença de 43,2 µg L-1 todas as estirpes tiveram seu crescimento severamente reduzido, não havendo diferença entre elas.

Palavras-chave: Herbicida, soja, inoculante, rizóbio, EPSPs.

ABSTRACT

Glyphosate applications to glyphosate-resistant soybean may impair symbiosis with Bradyrhizobium, a symbiotic bacterium. This study evaluated the sensitivity to glyphosate of three Bradyrhizobium strains used commercially in soybean crop in Brazil. The concentrations (0.0; 5.4; 10.8; 21.6 e 43.2 µg L^-1) of the active ingredient glyphosate [N­(phosphonomethyl)glycine] were added to YM liquid medium for the growth of one strain of B. japonicum (SEMIA 5079) and two strains of B. elkanni (SEMIA 5019 and SEMIA 587) inoculated as pure culture. The herbicide effect on the growth of the tested strains was assessed by optical density and growth curves were established for each strain. Reduction in growth of strains in the lowest glyphosate concentration were 18% for SEMIA 5079, 29% for SEMIA 5019 and 35% for SEMIA 587. In general, the higher the concentration of the herbicide in the culture medium, the greater the growth inhibition. The strains showed differential sensitivity only at the lowest concentrations of glyphosate, allowing the determination of the following order of sensitivity: SEMIA 587>SEMIA 5019>SEMIA 5079. This differential sensitivity is dependent on the herbicide concentration, since in the presence of 43.2 µg L^-1 all strains severely reduced growth, not showing difference among them.

Key words: Herbicide, soybean, inoculant, rhizobium, EPSPs.

Texto completo disponível apenas em PDF.

Full text available only in PDF format.

Recebido para publicação em novembro de 2008 e aprovado em setembro de 2009

• Arruda JS, Lopes NF & Moura AB (2001) Behavior of Bradyrhizobium japonicum strains under different herbicide concentrations. Planta Daninha, 19:111-117.
• Borges AC, Guimaraes WV, Muchovej RMC & Gonzales GR (1990) Resistance of Bradyrhizobium japonicum strains to different fungicides and herbicides. World Journal of Microbiology and Biotechnology, 6:428-430.
• Buchanan BB, Gruissem W & Jones RL (2000) Biochemistry and molecular biology of plants. Rockville, ASPP. 1367p.
• Caldwell DR (1999) Microbial physiology and metabolism. ^2a ed. Belmont, Star. 403p.
• Eberbach PL & Douglas LA (1989) Herbicide effects on the growth and nodulation potential of Rhizobium trifolii with Trifolium subterraneum Plant and Soil, 119:15-23.
• Embrapa (2009) Soja – dados econômicos. Disponível em: <http://www.cnpso.embrapa.br/index.php?op_page=294&cod_pai=17>. Acessado em: 21 de maio de 2009.
• Hernandez A, Garcia-Plazaola JI & Becerril JM (1999) Glyphosate effects on phenolic metabolism of nodulated soybean (Glycine max L. Merr.). Journal of Agricultural Food and Chemistry, 47:2920-2925.
• King AC, Purcell, LC & Vories ED (2001) Plant growth and nitrogenase activity of glyphosate-tolerant soybean in response to glyphosate applications. Agronomy Journal, 93:179-186.
• Liu CM, McLean PA, Sookdeo CC & Cannon FC (1991) Degradation of the herbicide glyphosate by members of the family Rhizobiaceae. Applied and Environmental Microbiology, 57:1799-1804.
• Mallik MAB & Tesfai K (1985) Pesticidal effect on soybeanrhizobia symbiosis. Plant and Soil, 85:33-41.
• Moorman TB (1986) Effects of herbicides on the survival of Rhizobium japonicum strains. Weed Science, 34:628-633.
• Moorman TB, Becerril JM, Lydon J & Duke SO (1992) Production of hydroxybenzoic acids by Bradyrhizobium japonicum strains after treatment with glyphosate. Journal of Agricultural Food and Chemistry, 40:289-293.
• Padgette SR, Kolacz KH, Delannay X, Re DB & La Vallee BJ (1995) Development, identification, and characterization of a glyphosate-tolerant soybean line. Crop Science, 35:1451-1461.
• Prell J & Poole P (2006) Metabolic changes of rhizobia in legume nodules. Trends in Microbiology, 14:161-168.
• Reddy KN, Hoagland RE & Zablotowicz RM (2000) Effect of glyphosate on growth, chlorophyll content and nodulation in glyphosate-resistant soybeans (Glycine max) varieties. Journal of New Seeds, 2:37-52.
• Reddy KN & Zablotowicz RM (2003) Glyphosate-resitant soybean response to various salts of glyphosate and glyphosate accumulation in soybean. Weed Science, 51:496-502.
• Santos JB, Ferreira EA, Kasuya MCM, Da Silva AA & Procopio SDO (2005) Tolerance of Bradyrhizobium strains to glyphosate formulations. Crop Protection, 24:543-547.
• Schulz A, Krüper A & Amrhein N (1985) Differential sensitivity of bacterial 5-enolpyruvylshikimate- 3 -phosphate synthases to the herbicide glyphosate. FEMS Microbiology Letters, 28:297-301.
• Zabaloy MC & Gómez MA (2005) Diversity of rhizobia isolated from an agricultural soil in Argentina based on carbon utilization and effects of herbicides on growth. Biology and Fertility of Soils, 42:83-88.
• Zablotowicz RM & Reddy KN (2004) Impact of glyphosate on the Bradyrhizobium japonicum symbiosis with glyphosateresistant transgenic soybean: a minireview. Journal of Environmental Quality, 33:825-831.

Datas de Publicação

• Publicação nesta coleção
  09 Out 2012
• Data do Fascículo
  Fev 2010

Histórico

• Recebido
  Nov 2008
• Aceito
  Set 2009