Aplicación de la hipótesis de la centralidad del nicho ecológico para evaluar los cambios del metabloma y la actividad biológica en poblaciones de Eucryphia cordifolia Cav. (Cunoniaceae).
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Date
2023
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Universidad de Concepción.
Abstract
La hipótesis de la centralidad del nicho ecológico establece que la abundancia de la población está determinada por la posición en el nicho ecológico, esperándose mayores abundancias hacia el centro del nicho y menores en la periferia. Sin embargo, las variaciones en las condiciones que favorecen la persistencia de las poblaciones entre el centro y la periferia del nicho pueden ser un sustituto de factores de estrés que se reflejan en la producción de metabolitos en las plantas. Esta investigación se basó en un enfoque multidisciplinario entre la hipótesis de la centralidad del nicho ecológico y la metabolómica como una herramienta que permite predecir la presencia de compuestos con interés biotecnológico, dirigiendo el muestreo y con ello evitando sobreexplotación de los recursos nativos. En esta tesis se evaluaron las siguientes hipótesis (1) Las poblaciones de E. cordifolia que se encuentran en la periferia del nicho ecológico presentan una mayor abundancia y/o diversidad de metabolitos secundarios que poblaciones que se distribuyen en el centro del nicho ecológico (2) Los metabolitos secundarios sintetizados por poblaciones de E. cordifolia que se distribuyen en la periferia del nicho ecológico, presentan una mayor actividad biológica (e.g., antioxidante y antimicrobiana) comparados con poblaciones distribuidas en el centro del nicho ecológico. Se emplearon tres enfoques metodológicos: primero, modelamos el nicho ecológico para determinar la idoneidad ambiental de E. cordifolia y seleccionar poblaciones centrales y periféricas para el muestreo en campo (objetivo 1). Segundo, aplicamos análisis de ordenamiento (PCA y NMDS) y el índice de diversidad de Shannon Wiener para evaluar la diversidad metabólica entre las poblaciones y en diferentes estaciones (objetivo 2). Luego, mediante OPLS-DA, identificamos metabolitos diferenciadores entre la población central y periférica. En tercer término, se evaluó la actividad antioxidante y antimicrobiana contra cinco microorganismos de interés en salud pública, hipotetizando un efecto significativo en la población periférica (objetivo 3). Los resultados del capítulo 2 indicaron que: las localidades centrales y periféricas de E. cordifolia en Chile no siguen un gradiente ambiental latitudinal evidente. La similitud metabólica entre poblaciones se explica más por la estacionalidad que por la posición en el nicho. La tendencia en la diversidad metabolómica aumenta a medida que nos alejamos del centro del nicho ecológico. Los análisis multivariados permitieron una diferenciación metabólica entre las poblaciones. En la población periférica (Puerto Montt) se identificaron derivados de quercetina, kaempferol-3-O-ramnósido, luteolina y procianidina B a lo largo de las estaciones, estando ausentes en la población central (Coronel). En cuanto a los análisis antioxidantes, estos variaron a lo largo de las estaciones, donde las poblaciones más cercanas a la periferia alcanzaron una alta capacidad antioxidante. Respecto a los ensayos microbianos, los extractos mostraron una fuerte inhibición en las etapas iniciales de crecimiento microbiano, pero no fueron eficientes en la inhibición de la formación de biopelículas en cuatro de los microorganismos estudiados. En última instancia, nuestros resultados respaldan la utilidad de este enfoque multidisciplinario para prever variaciones en el metaboloma con posibles aplicaciones biotecnológicas y nos orienta a realizar muestreos eficientes.
The ecological niche centrality hypothesis states that species abundance is determined by position in the ecological niche, with higher abundances expected towards the centre of the niche and lower abundances at the periphery. However, variations in conditions that favour the persistence of populations between the centre and periphery of the niche may be a proxy for stress factors that are reflected in plant metabolite production. This research was based on a multidisciplinary approach between the hypothesis of ecological niche centrality and metabolomics as a predictive tool to predict the presence of compounds with biotechnological interest, directing sampling and thus avoiding overexploitation of native resources. In this thesis the following hypotheses were evaluated (1) E. cordifolia populations found in the periphery of the ecological niche have a higher abundance and/or diversity of secondary metabolites than populations distributed in the centre of the ecological niche (2) Secondary metabolites synthesized by E. cordifolia populations distributed in the periphery of the ecological niche have a higher biological activity (e.g., antioxidant and antimicrobial) compared to populations distributed in the centre of the ecological niche. Three methodological approaches were employed: first, we modelled the ecological niche to determine the environmental suitability of E. cordifolia and selected core and peripheral populations for field sampling (objective 1). Second, we applied ordination analyses (PCA and NMDS) and the Shannon Wiener diversity index to assess metabolic diversity among populations and in different seasons (objective 2). Then, using OPLS-DA, we identified differentiating metabolites between the central and peripheral populations. Thirdly, antioxidant and antimicrobial activity was evaluated against five microorganisms of public health interest, hypothesising a significant effect in the peripheral population (objective 3). The results of chapter 2 indicated that: central and peripheral localities of E. cordifolia in Chile do not follow an obvious latitudinal environmental gradient. Metabolic similarity between populations is explained more by seasonality than by niche position. The trend in metabolomic diversity increases as we move away from the centre of the ecological niche. Multivariate analyses allowed metabolic differentiation between populations. In the peripheral population (Puerto Montt), quercetin, kaempferol-3-O-rhamnoside, luteolin and procyanidin B derivatives were identified throughout the seasons, while they were absent in the central population (Coronel). Antioxidant assays varied across the seasons, with populations closer to the periphery achieving high antioxidant capacity. Regarding microbial assays, the extracts showed strong inhibition in the initial stages of microbial growth but were not efficient in inhibiting biofilm formation in four of the microorganisms studied. Ultimately, our results support the usefulness of this multidisciplinary approach for predicting variations in the metabolome with potential biotechnological applications and guide us to efficient sampling.
The ecological niche centrality hypothesis states that species abundance is determined by position in the ecological niche, with higher abundances expected towards the centre of the niche and lower abundances at the periphery. However, variations in conditions that favour the persistence of populations between the centre and periphery of the niche may be a proxy for stress factors that are reflected in plant metabolite production. This research was based on a multidisciplinary approach between the hypothesis of ecological niche centrality and metabolomics as a predictive tool to predict the presence of compounds with biotechnological interest, directing sampling and thus avoiding overexploitation of native resources. In this thesis the following hypotheses were evaluated (1) E. cordifolia populations found in the periphery of the ecological niche have a higher abundance and/or diversity of secondary metabolites than populations distributed in the centre of the ecological niche (2) Secondary metabolites synthesized by E. cordifolia populations distributed in the periphery of the ecological niche have a higher biological activity (e.g., antioxidant and antimicrobial) compared to populations distributed in the centre of the ecological niche. Three methodological approaches were employed: first, we modelled the ecological niche to determine the environmental suitability of E. cordifolia and selected core and peripheral populations for field sampling (objective 1). Second, we applied ordination analyses (PCA and NMDS) and the Shannon Wiener diversity index to assess metabolic diversity among populations and in different seasons (objective 2). Then, using OPLS-DA, we identified differentiating metabolites between the central and peripheral populations. Thirdly, antioxidant and antimicrobial activity was evaluated against five microorganisms of public health interest, hypothesising a significant effect in the peripheral population (objective 3). The results of chapter 2 indicated that: central and peripheral localities of E. cordifolia in Chile do not follow an obvious latitudinal environmental gradient. Metabolic similarity between populations is explained more by seasonality than by niche position. The trend in metabolomic diversity increases as we move away from the centre of the ecological niche. Multivariate analyses allowed metabolic differentiation between populations. In the peripheral population (Puerto Montt), quercetin, kaempferol-3-O-rhamnoside, luteolin and procyanidin B derivatives were identified throughout the seasons, while they were absent in the central population (Coronel). Antioxidant assays varied across the seasons, with populations closer to the periphery achieving high antioxidant capacity. Regarding microbial assays, the extracts showed strong inhibition in the initial stages of microbial growth but were not efficient in inhibiting biofilm formation in four of the microorganisms studied. Ultimately, our results support the usefulness of this multidisciplinary approach for predicting variations in the metabolome with potential biotechnological applications and guide us to efficient sampling.
Description
Tesis para optar al grado de Doctor en Ciencias Biológicas área Botánica.