Caracterización de bacterias aerobias estrictas asociadas al suelo de ciruelo europeo en condiciones hídricas contrastantes
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Date
2024
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Universidad de Concepción
Abstract
Los microorganismos del suelo juegan roles fundamentales en el crecimiento de los cultivos, pero sus poblaciones pueden verse afectadas positiva o negativamente por cambios en la condiciones climáticas y edáficas. El objetivo de esta tesis fue caracterizar bacterias aerobias estrictas aisladas de un suelo con condiciones hídricas contrastantes, en cuanto a sus atributos promotores de crecimiento vegetal. Se cuantificó bacterias aerobias estrictas (AE) en suelos sometidos a dos condiciones hídricas (DRY y WET) en un huerto de ciruelo europeo en super alta densidad. El porcentaje de bacterias AE fue significativamente más bajo en la condición WET (P ≤ 0,05), aunque no se encontraron diferencias en las UFC por gramo de suelo. Las bacterias AE fueron caracterizadas en cuanto a su habilidad para fijar nitrógeno, solubilizar fósforo y potasio, además de evaluar la capacidad de producir la enzima ACC desaminasa. También se evaluó la producción de ácido indol acético y el antagonismo frente a Pseudomonas syringae pv. syringae, uno de los principales patógenos del ciruelo. Demostrándose que las bacterias AE cumplen roles principalmente asociados a la fijación biológica de nitrógeno y la producción de la enzima ACC-desaminasa y se determinó que la condición WET disminuyó las poblaciones de bacterias aerobias estrictas.
Soil microorganisms play fundamental roles in crop growth, but their populations can be positively or negatively affected by changes in climatic and edaphic conditions. The objective of this thesis was to characterize obligate aerobic bacteria isolated from a soil with contrasting water conditions, in terms of their plant growth promoting attributes. Obligate aerobic bacteria (OAB) were quantified in soils subjected to two water conditions (DRY and WET) in a European plum orchard at super high density. The percentage of OAB was significantly lower in the WET condition (P ≤ 0.05), although no differences in CFU per gram of soil were found. The OAB were characterized in terms of their ability to fix nitrogen, solubilize phosphorus and potassium, in addition to evaluating the ability to produce the enzyme ACCdesaminase. Indole acetic acid production and antagonism against Pseudomonas syringae pv. syringae, one of the main plum pathogens, were also evaluated. It was demonstrated that OAB play roles mainly associated with biological nitrogen fixation and the production of the ACC desaminase enzyme, and it was determined that the WET condition decreased the populations of obligate aerobic bacteria.
Soil microorganisms play fundamental roles in crop growth, but their populations can be positively or negatively affected by changes in climatic and edaphic conditions. The objective of this thesis was to characterize obligate aerobic bacteria isolated from a soil with contrasting water conditions, in terms of their plant growth promoting attributes. Obligate aerobic bacteria (OAB) were quantified in soils subjected to two water conditions (DRY and WET) in a European plum orchard at super high density. The percentage of OAB was significantly lower in the WET condition (P ≤ 0.05), although no differences in CFU per gram of soil were found. The OAB were characterized in terms of their ability to fix nitrogen, solubilize phosphorus and potassium, in addition to evaluating the ability to produce the enzyme ACCdesaminase. Indole acetic acid production and antagonism against Pseudomonas syringae pv. syringae, one of the main plum pathogens, were also evaluated. It was demonstrated that OAB play roles mainly associated with biological nitrogen fixation and the production of the ACC desaminase enzyme, and it was determined that the WET condition decreased the populations of obligate aerobic bacteria.
Description
Tesis presentada para optar al título de Ingeniero Agrónomo
Keywords
Suelos - Absorción y adsorción - Chile, Ciruelo, Pseudomonas