Publication: Aplicación biotecnológica de bacterias rizosféricas: elicitación de sistemas defensivos sistémicos en relación con la producción de compuestos con interés farmacológico y alimentario
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2016-08-04
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Universidad Complutense de Madrid
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Abstract
Esta memoria se basa en la hipótesis del papel fundamental que el sistema microbiano asociado al sistema radical de las plantas tiene sobre el metabolismo vegetal y las consiguientes aplicaciones de los productos derivados del mismo. El sistema rizosférico microbiano, el microbioma rizosférico cumple un papel fundamental para que la planta consiga mejorar sus capacidades de adaptación a un ambiente cambiante. En el capítulo 2 se exponen de manera enlazadas hipótesis sucesivas que pretenden evidenciar el potencial de aplicación de las bacterias asociadas a la planta y los distintos enfoques de aplicación biotecnológicos. En primer lugar, se plantea el uso de la rizosfera como fuente de microorganismos especialmente adaptados a la interacción del sistema planta/microorganismos. Un sistema en el que la presión selectiva definida por la planta condiciona el tipo de microorganismos, su diversidad y en definitiva la estructura de las comunidades microbianas que se desarrollan en este ecosistema. Sobre la hipótesis de la capacidad de selección de microorganismos por la planta, primero se busca una planta que aporte una serie de factores de presiónselección. La planta se elige en base a criterios filogenéticos y metabólicos (metabolismo secundario muy activo). Nicotiana glauca, es una Solanacea, de la misma familia que especies con gran interés alimentario, como el tomate, Solanum lycopersicum, la patata, Solanum tuberosum o el pimiento, Capsicum annum. Se selecciona esta planta como sujeto de muestreo rizosférico, en busca de un microbioma cultivable y con aplicaciones por sus aportaciones beneficiosas en la interacción. A continuación, sobre las casi mil cepas aisladas de la rizosfera, a lo largo de dos años, en tres suelos de características muy diferentes, se realiza un ensayo previo de actividades con potencial para incidir favorablemente sobre la salud de la planta. Las cepas se seleccionan sobre la base de un screening a gran escala en el que se intenta absorber la máxima variabilidad genética de los microorganismos que se desarrollan en el sistema rizosférico de Nicotiana glauca y pasan a estudiarse por su capacidad para inducir resistencia sistémica y efectos sobre el crecimiento en plantas de tomate, especie elegida como modelo de trabajo...
The present study focuses on the microbial system associated to plant roots, its key role on plant metabolism and the direct applications to obtain derived products. The rhizosphere microbiome dramatically affects the metabolic changes relevant for plant adaptations to environmental changes. The results presented on chapter 2 arise from consecutive hypothesis that progressively evidence the huge potential of delivering natural beneficial bacteria to plants for different biotechnological applications. The type of microorganisms and diversity of the same present in the rhizosphere of a plant is determined by the plant through a number of factors, among which are phylogenetic and metabolic criteria. Based on this statement, Nicotiana glauca, was identified as a good candidate to provide beneficial microorganisms for two reasons; first, this genera has an active secondary metabolism. Secondly, it has a phylogenetic relationship with other species relevant for human nutrition such as tomatoes, (Solanum lycopersicum), potatoes, (Solanum tuberosum) or peppers (Capsicum annum) since it belongs to the Solanaceae family. Hence, a screening for PGPR was carried out within the culturable microbiome in order to isolate bacterial strains with a good biotechnological potential. The screening was designed along two years, on three different soils and two phenological moments of the plant in order to absorb the maximum genetic variability of the microorganisms that inhabit the rhizosphere of Nicotiana glauca. The screening for putative PGPR traits was done on 1000 isolates based on biochemical tests, and the best six strains are further evaluated for their ability to enhance growth and induce systemic resistance on tomato as the model plant. Once the most effective strains to trigger systemic resistance in tomato are identified, a basic study of the molecular factors involved in the response and the mechanisms of signal transduction are studied in the model plant Arabidopsis thaliana in the second block...
The present study focuses on the microbial system associated to plant roots, its key role on plant metabolism and the direct applications to obtain derived products. The rhizosphere microbiome dramatically affects the metabolic changes relevant for plant adaptations to environmental changes. The results presented on chapter 2 arise from consecutive hypothesis that progressively evidence the huge potential of delivering natural beneficial bacteria to plants for different biotechnological applications. The type of microorganisms and diversity of the same present in the rhizosphere of a plant is determined by the plant through a number of factors, among which are phylogenetic and metabolic criteria. Based on this statement, Nicotiana glauca, was identified as a good candidate to provide beneficial microorganisms for two reasons; first, this genera has an active secondary metabolism. Secondly, it has a phylogenetic relationship with other species relevant for human nutrition such as tomatoes, (Solanum lycopersicum), potatoes, (Solanum tuberosum) or peppers (Capsicum annum) since it belongs to the Solanaceae family. Hence, a screening for PGPR was carried out within the culturable microbiome in order to isolate bacterial strains with a good biotechnological potential. The screening was designed along two years, on three different soils and two phenological moments of the plant in order to absorb the maximum genetic variability of the microorganisms that inhabit the rhizosphere of Nicotiana glauca. The screening for putative PGPR traits was done on 1000 isolates based on biochemical tests, and the best six strains are further evaluated for their ability to enhance growth and induce systemic resistance on tomato as the model plant. Once the most effective strains to trigger systemic resistance in tomato are identified, a basic study of the molecular factors involved in the response and the mechanisms of signal transduction are studied in the model plant Arabidopsis thaliana in the second block...
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Tesis inédita de la Universidad Complutense de Madrid, Facultad de Farmacia, leída el 01-02-2016