Characterization of variants of Bradyrhizobium elkanii and B. japonicum and symbiotic behaviour in soybeans

Kober, M.; Sá, Enílson Luiz Saccol de; Freire, J. R. Jardim; Giongo, Adriana

doi:10.1590/s0103-84782004000500020

Cited by 6 publications

(7 citation statements)

References 18 publications

(17 reference statements)

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“…No conclusive evidence has been reported in which morphological variation in the Bradyrhizobium colony interfered with the symbiotic characteristics of the variant isolates. Other authors (Fuhrmann, 1990;Basit et al, 1991;Kober et al, 2004;Carvalho et al, 2005) observed that variations in the cultural characteristics of Bradyrhizobium influenced symbiosis with soybean; however, no pattern in the morphology of the colonies explained such influence. Nevertheless, none of these studies were performed with strains in inoculants.…”

Section: Discussionmentioning

confidence: 96%

“…However, several studies have reported variations in the morphological, physiological, genetic, and symbiotic characteristics of Bradyrhizobium isolated from soils inoculated with commercial inoculants, and they attribute these variations to genetic adaptation to native microorganisms and recombination processes with them (Ferreira and Hungria, 2002;Galli-Terasawa et al, 2003;Barcellos et al, 2007;Batista et al, 2007;Giongo et al, 2008). However, inoculant strains of B. japonicum or B. elkanii, cultured under laboratory conditions, also produced colonies with distinct morphology and genotypes (Sylvester-Bradley et al, 1988;Basit et al, 1991;Kober et al, 2004), and they can change the symbiotic relationships with the host plant (Fuhrmann, 1990;Melchiorre et al, 2011;Torres et al, 2012). According to the intensity of this variation, rhizobia may lose nodulation ability or become less efficient in N 2 fixation.…”

Section: Introductionmentioning

confidence: 99%

“…According to the intensity of this variation, rhizobia may lose nodulation ability or become less efficient in N 2 fixation. Greenhouse experiments revealed that variability in the phenotypic characteristics of B. japonicum or B. elkanii strains of commercial inoculants affected the competitiveness of nodule formation, nodulation, and the efficiency of nitrogen fixation in soybean (Kober et al, 2004). Therefore, this is an important factor to consider in selection and approval of strains to be used as inoculants, as well as in quality control of the inoculants.…”

Section: Introductionmentioning

confidence: 99%

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Symbiotic Efficiency and Genotypic Characterization of Variants of Bradyrhizobium spp. in Commercial Inoculants for Soybeans

Barbosa

Costa

Ribeiro

et al. 2017

Rev. Bras. Ciênc. Solo

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High yields obtained from soybean [Glycine max (L.) Merrill], and consequent profits, are related to efficient symbiosis of soybean with nitrogen fixing bacteria of the Bradyrhizobium genus. Inoculation with strains belonging to the Bradyrhizobium japonicum, B. elkanii, and B. diazofficiens species, approved by the Brazilian Ministry of Agriculture (MAPA), is a common practice for this crop. However, variations in the composition of inoculants can change the quality of the product. The aim of this study was to genetically identify and to evaluate the symbiotic efficiency of isolates with cultural characteristics different from those of strains approved by MAPA and which are present in two commercial inoculants for soybean. Isolates obtained from inoculants and the strains SEMIA 5079 (CPAC 15), SEMIA 5080 (CPAC 7), SEMIA 587 (BR 96), and SEMIA 5019 (BR 29), indicated in the formulation of these inoculants, were tested for symbiotic efficiency in soybeans (cultivar: COODETEC 5G 830 RR) in a greenhouse. Identification by partial sequencing of the 16S rRNA gene, together with BOX-PCR analysis, showed that variant isolates were not similar to the inoculant strains indicated in the commercial products, despite belonging to the same genus and/or species. No loss was observed in the nodulation ability of the isolates; however, significant differences were reported in the symbiotic efficiency of the isolates compared to the inoculant strains approved by MAPA. Nevertheless, the presence of morphological variants did not influence the efficiency of inoculant products.

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Section: Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Symbiotic Efficiency and Genotypic Characterization of Variants of Bradyrhizobium spp. in Commercial Inoculants for Soybeans

Barbosa

Costa

Ribeiro

et al. 2017

Rev. Bras. Ciênc. Solo

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“…In fact, rhizobia are randomly distributed in growing soils where they compete with other indigenous strains (Denison and Kiers, 2004), which often form less efficient nodules (Simms and Taylor, 2002). However, the mechanisms which determine the relative competitiveness among strains are still poorly understood (Kober et al, 2004). The study of Glycine max-rhizobia association in the Guinea-savannah zone of Cameroon has revealed the efficiency of indigenous strains over the exotic ones (Megueni et al, 2006), although these later showed efficiency in other agroecological zones for Vigna unguiculata (Ngakou, 2007).…”

Section: Introductionmentioning

confidence: 99%

Study on the isolation and characterization of rhizobia strains as biofertilizer tools for growth improvement of four grain legumes in Ngaoundéré-Cameroon

Ngakou¹,

Clautilde²,

Ousseni³

et al. 2010

International Journal of Biological and Chemical Sciences

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Increasing the yield and economical efficiency of grain legumes in the Guinea-Savannah zone of Cameroon is a high researcher priority to assist growers in the rural areas. We report here a two-years study in the production process of fertilizer containing rhizobia for a sustainable production of grain legumes in the region. To address the issue, nodulation and rhizobia strains characterization were assessed at Dang and Wakwa, two soils different in trapping rhizobia partners for groundnut, bambara groundnut, cowpea and soybean. This was a prerequisite step in the determination of the most efficient rhizobia strains for biofertilizer production. Results indicate that all the four grain legumes differently formed nodules in their roots system in the two experimental soils. Cowpea and soybean demonstrated a highly significant (p 0.001) potential in fixing atmospheric nitrogen through their nodules than groundnut and bambara groundnut. The dry weight of nodules in groundnut and bambara groundnut was significantly lower (0.0001 < p 0.038) than that of cowpea and soybean in the two soils. When rhizobia were isolated from root nodules of plant species, the number of isolates ranged from 2 to 4 per grain legumes. All the isolates were convex in elevation, smooth/humid on the surface, with regular edges, except one groundnut colony from wakwa soil. The colonies were either whitish for soybean, whitish/yellowish for cowpea, groundnut and bambara groundnut. The rhizobia biofertilizer produced for each grain legumes were stored in the refrigerator for field tests. This is a step forward for further molecular characterization of isolates to enable production of elite inoculum in the region.

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“…Las poblaciones alóctonas de rizobios suelen contener aislados altamente competitivos, que interactúan eficientemente con las raíces de las leguminosas y las infectan, aunque estas simbiosis suelen ser poco eficientes en cuanto a la fijación de N 2 (Denison & Kiers 2004). La variabilidad entre las cepas de rizobios podría ser un factor importante a considerar en la selección y preservación de los cultivos para la producción de inoculantes (Kober & Giongo 2004 Tesis Doctoral 61 la raíz. Estos deben presentar una coloración interna rojiza, que indica la presencia de la leghemoglobina (Vincent 1970).…”

Section: Graciela N Pastorinounclassified

Diversidad de los rizobios que nodulan la soja en los suelos de la Pampa húmeda e identificación de cepas para la fabricación de inoculantes comerciales

Pastorino¹,

López²,

Lucentini³

et al.

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Las labores culturales, provocan modificaciones de las propiedades físicas, químicas y biológicas de los suelos. Estas se clasifican en: labranza convencional, labranza vertical y siembra directa. Cada tecnología de manejo genera estreses a los que las poblaciones microbianas se adaptan, como resultado de cambios morfológicos, fisiológicos y genéticos. La inoculación de la soja (Glycine max [L.] Merr) es una tecnología que se introdujo en la Argentina junto con el cultivo y por ello los inoculantes fueron el vehículo de ingreso de las cepas exóticas de Bradyrhizobium, que una vez incorporadas al suelo, se adaptaron y establecieron dando origen a las poblaciones de rizobios naturalizadas. Lo que condujo a generar diversidad a nivel del genoma de los bradyrizobios. El objetivo de este trabajo fue evaluar la diversidad de los simbiontes de soja que se encuentran en la población del suelo y el rol que cumple como recurso en la selección de cepas para la producción comercial de inoculantes. Se evaluaron dos muestras de suelo que durante los últimos 8 años fueron trabajados con siembra directa (SD) y con labranza convencional (LC). Se realizó el recuento y aislamiento de rizobios. Los aislados se caracterizaron fisiológica y genéticamente. La diversidad se evaluó mediante la amplificación de las secuencias BOX A1R. Se seleccionaron 52 aislados que se identificaron amplificando las regiones RSα y nifD y la secuenciación del fragmento ITS 16S - 23S rDNA. El recuento de rizobios mostró que en el suelo bajo SD y antecesor soja la población fue mayor que en la muestra de suelo bajo LC y antecesor maíz. La caracterización fisiológica de 200 aislados reflejó que los suelos LC contuvieron un mayor número de cepas tolerantes a salinidad y alta temperatura. Además un porcentaje mayor de aislados del suelo LC, respecto del suelo bajo SD, resultó con capacidad de sobrevivencia sobre semilla superior a la cepa control E109. Los aislados además presentaron diferencias en la nodulación y fijación de nitrógeno, en la tolerancia a glifosato y en la producción de ácido indol acético (AIA). Sólo un aislado mostró capacidad de solubilización de fósforo. El análisis del dendrograma generado con los fingerprints BOX A1R, mostró que hay mayor diversidad en los suelos bajo SD. Sobre los 52 aislados analizados en base a la secuencia del ITS se encontró que el 70 % son Bradyrhizobium japonicum y 30 % B. elkanii. Se identificaron 4 aislados que comparten características genéticas de ambas especies de Bradyrhizobium. En esta tesis se confirmó que en los suelos con historia de cultivo de soja, manejados bajo distintos sistemas de labranzas, se indujeron cambios a nivel del genoma de las cepas de rizobios que contribuyó a modificar la diversidad de la población. Las poblaciones naturalizadas son un recurso para la identificación de rizobios con características superiores para la fabricación de inoculantes, sin embargo es necesario profundizar las evaluaciones de la supervivencia, tolerancia, competitividad y promoción del crecimiento vegetal de rizobios naturalizados para emplearlos como bioinoculantes.

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Characterization of variants of Bradyrhizobium elkanii and B. japonicum and symbiotic behaviour in soybeans

Abstract: Variation in rhizobia strains isn't a desirable fact

Cited by 6 publications

References 18 publications

Symbiotic Efficiency and Genotypic Characterization of Variants of Bradyrhizobium spp. in Commercial Inoculants for Soybeans

Symbiotic Efficiency and Genotypic Characterization of Variants of Bradyrhizobium spp. in Commercial Inoculants for Soybeans

Study on the isolation and characterization of rhizobia strains as biofertilizer tools for growth improvement of four grain legumes in Ngaoundéré-Cameroon

Diversidad de los rizobios que nodulan la soja en los suelos de la Pampa húmeda e identificación de cepas para la fabricación de inoculantes comerciales

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