Integrated analysis of root microbiomes of soybean and wheat from agricultural fields

Root associated bacteria are critical for plant growth and health. Understanding the composition and role of root microbiota is crucial toward agricultural practices that are less dependent on chemical fertilization, which has known negative effects on the environment and human health. Here we analyzed the root-associated microbiomes of soybean and wheat under agricultural field conditions. We took samples from 11 different production fields across a large geographic area. We used 16S rRNA pyrosequencing to explore root microbial communities and also obtained 2,007 bacterial isolates from rhizospheres, which were tested for the presence of plant growth promoting (PGP) traits in-vitro. We observed that pH and nitrate content correlated with beta diversity variability of rhizospheric bacterial communities despite the variable field conditions. We described the dominant bacterial groups associated to roots from both crops at a large geographic scale and we found that a high proportion of them (60-70%) showed more than 97% similarity to bacteria from the isolated collection. Moreover, we observed that 55% of the screened isolates presented PGP activities in vitro. These results are a significant step forward in understanding crop-associated microbiomes and suggest that new directions can be taken to promote crop growth and health by modulating root microbiomes.Fil: Rascovan, Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Agrobiotecnología de Rosario; ArgentinaFil: Carbonetto, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Agrobiotecnología de Rosario; ArgentinaFil: Perrig, Diego Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Rizobacter Argentina S. A.; ArgentinaFil: Diaz, Marisa. Rizobacter Argentina S. A.; ArgentinaFil: Canciani, Wilter. Rizobacter Argentina S. A.; ArgentinaFil: Abalo, Matías. Rizobacter Argentina S. A.; ArgentinaFil: Alloati, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Agrobiotecnología de Rosario; ArgentinaFil: González Anta, Gustavo. Rizobacter Argentina S. A.; ArgentinaFil: Vazquez, Martin Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Agrobiotecnología de Rosario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin

Respuesta del establecimiento de Medicago sativa (Alfalfa) a la inoculación con bacterias solubilizadoras de fósforo (Pseudomonas fluorescens) y a la fertilización

Response of Medicago sativa establishment to inoculation with phosphate solubilizing bacteria (Pseudomonas fluorescens) and fertilizatio

Evaluation of bradyrhizobia strains isolated from field-grown soybean plants in Argentina as improved inoculants

Bradyrhizobium strains were isolated from nodules obtained from field-grown soybean plants sampled in 12 soybean production locations in Argentina. These fields had been annually cropped with soybean and did not show decreases in yields even though they had been neither N-fertilized nor inoculated for at least the last 5 years. We hypothesized that the isolated strains maintained high competitiveness and efficiency in fixing adequate N2 levels. A set of strains that showed the highest nodular occupancy in each sampling location were assayed for symbiotic performance under greenhouse and field conditions and comparatively evaluated with Bradyrhizobium japonicum E109, the strain officially recommended for inoculant formulation in Argentina. An inoculant pool, formed by four strains obtained from nodules collected from Cañada Rica, developed higher nodular biomass than B. japonicum E 109 in assays carried out in greenhouses under well irrigated conditions. Additionally, neither nodule production nor specific nitrogenase activity decreased with respect to B. japonicum E 109 when plants were drought stressed during 7 days from sowing. The mean yields obtained under field conditions and plotted against the principal component one (CP1) obtained with an additive main effect and multiplicative interaction (AMMI) model showed that the inoculant pool from Cañada Rica had higher contribution to yield than strain E 109, although with lower environmental stability. The inoculant pool from Cañada Rica could be considered an improved inoculant and be used for preliminary assays, to formulate inoculants in Argentina. © 2010 Springer-Verlag.Fil: Melchiorre, Mariana Noemi. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Unidad de Estudios Agropecuarios - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Estudios Agropecuarios; ArgentinaFil: de Luca, Marcos Javier. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Fitopatología y Fisiología Vegetal; ArgentinaFil: González Anta, Gustavo Gabriel. Universidad Nacional del Noroeste de la Provincia de Buenos Aires; ArgentinaFil: Suarez, Paola. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Fitopatología y Fisiología Vegetal; ArgentinaFil: Lopez, Carlos. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Cordoba. Estacion Experimental Agropecuaria Manfredi. Agencia de Extension Rural Rio Primero.; ArgentinaFil: Lascano, Hernan Ramiro. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Unidad de Estudios Agropecuarios - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Estudios Agropecuarios; ArgentinaFil: Racca, Roberto Walter. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Fitopatología y Fisiología Vegetal; Argentin

Agronomic efficiency and genome mining analysis of the wheat-biostimulant rhizospheric bacterium Pseudomonas pergaminensis sp. nov. strain 1008T

Díaz M, Bach T, González Anta G, et al. Agronomic efficiency and genome mining analysis of the wheat-biostimulant rhizospheric bacterium Pseudomonas pergaminensis sp. nov. strain 1008T. Frontiers in Plant Science. 2022;13: 894985.Pseudomonas sp. strain 1008 was isolated from the rhizosphere of field grown wheat plants at the tillering stage in an agricultural plot near Pergamino city, Argentina. Based on its in vitro phosphate solubilizing capacity and the production of IAA, strain 1008 was formulated as an inoculant for bacterization of wheat seeds and subjected to multiple field assays within the period 2010–2017. Pseudomonas sp. strain 1008 showed a robust positive impact on the grain yield (+8% on average) across a number of campaigns, soil properties, seed genotypes, and with no significant influence of the simultaneous seed treatment with a fungicide, strongly supporting the use of this biostimulant bacterium as an agricultural input for promoting the yield of wheat. Full genome sequencing revealed that strain 1008 has the capacity to access a number of sources of inorganic and organic phosphorus, to compete for iron scavenging, to produce auxin, 2,3-butanediol and acetoin, and to metabolize GABA. Additionally, the genome of strain 1008 harbors several loci related to rhizosphere competitiveness, but it is devoid of biosynthetic gene clusters for production of typical secondary metabolites of biocontrol representatives of the Pseudomonas genus. Finally, the phylogenomic, phenotypic, and chemotaxonomic comparative analysis of strain 1008 with related taxa strongly suggests that this wheat rhizospheric biostimulant isolate is a representative of a novel species within the genus Pseudomonas, for which the name Pseudomonas pergaminensis sp. nov. (type strain 1008T= DSM 113453T= ATCC TSD-287T) is proposed

Biocontrol potential index of pseudomonads, instead of their direct-growth promotion traits, is a predictor of seed inoculation effect on crop productivity under field conditions

Agricultural bioproducts became interesting alternatives for sustainable agricultural practices, because they aim to reduce the use of agrochemicals without losing crop yields. As Pseudomonas genus has been largely studied for the high number of plant probiotic species it contains, in this work we evaluated the field performance of 10 genetically diverse native Pseudomonas that have been isolated from productive plots of the Argentine Pampas. Previously, they have been characterized in vitro, and we have developed several indexes to organize the isolates’ collection based on their potential to perform biocontrol of fungal pathogens (BPI), to promote plant growth by direct mechanisms (DGPI), or by integrated direct plus indirect mechanisms (PGPI). At three geographical sites, we tested the effect of single- and co-inoculations with a commercial bio-input based on the fungus Trichoderma harzianum Th2, in wheat and maize crops during 3 consecutive seasons. Most of single inoculations improved wheat and maize grain yields. For wheat, improvement seemed to be related with a higher plant emergence by the positive correlation between yield and plant number; whereas for maize increased yields would be rather associated with a better plant structure by the positive correlation between yield and the vegetation index NDVI. The co-inoculation of Th2 with different P. chlororaphis isolates also increased the grain yield of both grain crops, despite P. chlororaphis strains displayed fungal inhibition in dual culture in vitro tests. We found a positive and significant correlation between BPI and the yield percentage improvement of both crops, but a negative correlation with DGPI. Thus, this work shows the usefulness of the in vitro characterization of biocontrol-related traits and the estimation of a biocontrol potential index as a proxy for crop yield performance, but not of direct plant growth-promoting features.Fil: Agaras, Betina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes; ArgentinaFil: Noguera, Fabián. No especifíca;Fil: González Anta, Gustavo Gabriel. Universidad Nacional del Noroeste de la Provincia de Buenos Aires; ArgentinaFil: Wall, Luis Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Valverde, Claudio Fabián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes; Argentin

Recursos genéticos de judía común (Phaseolus vulgaris L.) y sus rizobios asociados en suelos de su centro de origen andino (proyecto CSIC i-COOP 2016SU0004)

8 páginas.- Contribución en el VI Seminario de Judía y en el Seminario sobre la eficiencia del sistema simbiótico Phaseolus-Rhizobium celebrado en la Estación Experimental del Zaidín (CSIC, Granada) los días 25 y 26 de Octubre de 2016.[EN] The project covers two topics: (i) legumes, common bean: its genetic diversity and its cultivation; and (ii) soils: their diversity and the associated microbiota (rhizobia). The objectives of the project are to complete the collection of wild and primitive common bean germplasm of the Argentinean Northwest gene bank (BANDA) of the Agricultural Experiment Station (EEA) - National Institute of Agricultural Technology (INTA) of Argentina. Also, to contribute to the knowledge of the biodiversity of the wild and primitive populations of common bean from the northwest of Argentina (NOA) of the Andean center of domestication of the species and to determine the degree of introgression of the wild populations. Likewise, it is proposed to analyze the diversity and physicochemical properties of the soils of bean cultivation, the isolation and taxonomic identification of the rhizobia strains of the nodules and the analysis of the most efficient rhizobia-bean symbiotic interactions to achieve higher bean yield.[ES] El proyecto abarca dos temas: ¡) las leguminosas, la judía o poroto común: su diversidad genética y su cultivo y ii) los suelos: su diversidad y la microbiota (rizobios) asociada. Los objetivos del proyecto se orientan a completar la colección de germoplasma silvestre y primitivo de judía/poroto del Banco de germoplasma del Noroeste Argentino (BANDA) de la Estación Experimental Agropecuaria (EEA)-Salta del Instituto Nacional de Tecnología Agropecuaria (INTA) de Argentina; contribuir al conocimiento de la biodiversidad de las poblaciones silvestres y primitivas de judía común/poroto del noroeste de Argentina (NOA) del centro de domesticación andino y determinar el grado de introgresión en las poblaciones silvestres. Asimismo se plantea analizarla diversidad y propiedades físico-químicas delos suelos de cultivo de judía/poroto y aislamiento e identificación taxonómica delas cepas de rizobios delos nódulos; y análisis de las interacciones simbióticas rizobios—judía más eficientes para conseguir mayor rendimiento de la judía/poroto.Los autores agradecen el apoyo del Consejo Superior de Investigaciones Científicas (CSIC, España, proyecto i—CCCP 2016SU0004) y del Instituto Nacional de Tecnología Agropecuaria (INTA, Argentina).N