http://hdl.handle.net/10366/130154 2026-05-01T19:31:01Z http://hdl.handle.net/10366/169842 [ES] El uso indiscriminado de fertilizantes y pesticidas químicos en los sistemas agrícolas ha provocado una degradación progresiva de la calidad del suelo, alteraciones en la estructura y funcionalidad de las comunidades microbianas, así como la contaminación de otros ecosistemas. Frente a esta problemática ambiental, las bacterias promotoras del crecimiento vegetal (PGPB) se presentan como una alternativa biotecnológica sostenible, con el potencial de mantener o incluso mejorar el rendimiento de los cultivos sin comprometer la salud del ecosistema. El potencial de las PGPB se basa en diversos mecanismos, entre los que se destacan la colonización eficiente de tejidos vegetales en uno o varios hospedadores, la capacidad de facilitar la disponibilidad de nutrientes esenciales y la modulación de los niveles hormonales en las plantas. A través de estos mecanismos, dichas bacterias pueden influir de manera determinante en procesos fisiológicos clave, tales como la modificación de la arquitectura del sistema radicular, lo que favorece la adaptación del hospedador a su entorno, potencia interacciones sinérgicas con otros microorganismos beneficiosos y promueve una mayor resistencia frente a condiciones adversas como sequía o la salinidad. Las cepas bacterianas que presentan estas características se consideran candidatas para el desarrollo de bioinoculantes, susceptibles de ser formulados, producidos a escala industrial, distribuidos y aplicados en sistemas agrícolas. No obstante, los buenos resultados de estos bioinoculantes in vitro no garantizan la efectividad del producto bajo condiciones reales. Por tanto, durante el proceso de formulación es indispensable evaluar aspectos críticos como la estabilidad del producto, su vida útil y, fundamentalmente, su eficacia bajo condiciones no controladas. En este contexto, la cepa Pseudomonas sp. CDVBN10, endófito de raíces de colza, ha demostrado tener potencial como PGPB. Análisis genómicos y bioquímicos han evidenciado su capacidad para producir sideróforos, solubilizar fosfatos, sintetizar ácido indol-3-acético (AIA), presentar actividad ACC desaminasa y formar biofilm en la superficie radicular. Ensayos funcionales adicionales confirmaron su eficacia para promover el crecimiento de colza y cultivos hortícolas como espinaca y cilantro (Jiménez-Gómez, 2020; Jiménez-Gómez et al., 2020). La cepa CDVBN10-B deriva de la cepa CDVBN10, pero cuenta con una deleción genómica de origen desconocido que fue descubierta tras finalizar la presente tesis doctoral. No obstante, nuestros estudios han demostrado que esta cepa sigue manifestando las citadas propiedades. El objetivo general de la presente tesis doctoral es profundizar en la caracterización funcional de la cepa Pseudomonas sp. CDVBN10-B como un bioinoculante de amplio espectro. Para ello, se plantea la caracterización exhaustiva de su potencial como PGPB en cultivos de interés agronómico, la evaluación de los mecanismos moleculares implicados en su interacción con la planta, la remodelación de la arquitectura radicular y la inducción de resistencia sistémica, así como el diseño de un bioinoculante efectivo para su aplicación en condiciones de campo.; [EN] The indiscriminate use of chemical fertilizers and pesticides in agricultural systems has led to progressive soil degradation, disruptions in the structure and functionality of microbial communities, and contamination of surrounding ecosystems. In response to this environmental challenge, plant growth-promoting bacteria (PGPB) have emerged as a sustainable biotechnological alternative with the potential to maintain or even enhance crop yields without compromising ecosystem health. The potential of PGPB relies on several mechanisms, including efficient colonization of plant tissues in one or more hosts, enhanced availability of essential nutrients, and modulation of plant hormone levels. Through these mechanisms, PGPB can significantly influence key physiological processes such as the modification of root system architecture, thereby improving host adaptation to environmental conditions, facilitating synergistic interactions with other beneficial microorganisms, and enhancing tolerance to abiotic stresses such as drought and salinity. Bacterial strains exhibiting these traits are considered suitable candidates for the development of bioinoculants that can be formulated, produced at an industrial scale, distributed, and applied in agricultural systems. However, successful in vitro performance does not necessarily guarantee product effectiveness under field conditions. Thus, formulation development must include the assessment of critical factors such as product stability, shelf life, and, above all, efficacy under non-controlled environments. In this context, Pseudomonas sp. CDVBN10, an endophyte isolated from rapeseed roots, has demonstrated potential as PGPB. Genomic and biochemical analyses revealed its ability to produce siderophores, solubilize phosphate, synthesize indole-3-acetic acid (IAA), exhibit ACC deaminase activity, and form biofilms on root surfaces. Additional functional assays confirmed its capacity to promote the growth of rapeseed and horticultural crops such as spinach and coriander (Jiménez-Gómez, 2020; Jiménez-Gómez et al., 2020). CDVBN10-B, a derivative of strain CDVBN10, was later found to harbor a genomic deletion of unknown origin, identified upon completion of this doctoral thesis. Nevertheless, our studies have shown that this strain retains the aforementioned properties. The overall objective of this doctoral thesis is to conduct an in-depth functional characterization of Pseudomonas sp. CDVBN10-B as a broad-spectrum bioinoculant. This includes a comprehensive evaluation of its potential as PGPB in crops of agronomic interest, investigation of the molecular mechanisms involved in its interaction with host plants, its role in remodeling root architecture and inducing systemic resistance, and the development of an effective bioinoculant suitable for field application. 2025-01-01T00:00:00Z http://hdl.handle.net/10366/169778 [ES] Colletotrichum es un género de hongos filamentosos fitopatógenos que causan la enfermedad de la antracnosis. Colletotrichum graminicola es el agente causal de la antracnosis del maíz (Zea mays), una enfermedad de gran impacto económico cuya incidencia está en aumento en distintas regiones del mundo y cuyos principales síntomas son el tizón foliar y la pudrición del tallo. Su éxito infeccioso depende en gran medida de la acción de proteínas efectoras, muchas de las cuales permanecen poco caracterizadas. Esta Tesis Doctoral se centró en dos efectores nucleares clave que son parálogos entre sí: CgEP4 y CgEP1 (Colletorichum graminicola Effector Protein 4 and 1). El estudio de CgEP4 reveló que se trata de un efector con localización nuclear altamente conservado, originado por una duplicación ancestral, cuya función resulta indispensable para la virulencia. Este gen está altamente conservado entre aislados de campo de C. graminicola de distintos continentes, lo que subraya su importancia biológica. A nivel experimental, se comprobó que CgEP4 se expresa de manera específica durante las fases iniciales de la infección y se transloca al núcleo de las células de maíz. Los mutantes de deleción mostraron una notable reducción en la capacidad de penetración y colonización, así como una activación fuerte de defensas basales en el hospedador, lo que indica que este efector cumple un papel esencial en la supresión de respuestas inmunitarias tempranas. Además, los ensayos in vitro revelaron que su ausencia altera procesos fúngicos fundamentales como el crecimiento, la esporulación y la tolerancia al estrés oxidativo y salino, lo que apunta a una doble función de CgEP4: actuar sobre el hospedador y, al mismo tiempo, regular aspectos internos de la fisiología del hongo. El análisis de CgEP1 se centró en la influencia de las repeticiones en tándem que presenta en su secuencia sobre la virulencia. A partir de un conjunto de aislados naturales se identificaron variantes alélicas que diferían en el número de repeticiones intragénicas (entre 5 y 8), lo que permitió establecer una relación directa entre la arquitectura del gen y la virulencia. Experimentos de complementación funcional demostraron que se requieren al menos siete repeticiones para mantener la virulencia, mientras que alelos con menos repeticiones pierden eficacia infecciosa y se comportan como mutantes nulos. Modelados estructurales realizados con AlphaFold2 confirmaron que la pérdida de repeticiones compromete la estabilidad tridimensional de la proteína, explicando la pérdida de función. A nivel transcriptómico, se comprobó que CgEP1 no solo suprime genes de defensa en las primeras etapas de la infección, sino que también reprograma el metabolismo del maíz en fases posteriores, favoreciendo la colonización. De forma paralela, en el propio hongo regula la expresión de genes asociados a la biosíntesis proteica, al metabolismo energético y a enzimas de degradación de la pared vegetal, reforzando su papel como efector multifuncional capaz de coordinar tanto la respuesta del hospedador como la del patógeno. En conjunto, esta tesis doctoral demuestra que CgEP4 y CgEP1 son efectores nucleares fundamentales para la virulencia de C. graminicola. Ambos casos ilustran la complejidad de las interacciones planta-patógeno y aportan nuevas perspectivas para el diseño de estrategias de control frente a la antracnosis del maíz. 2025-01-01T00:00:00Z http://hdl.handle.net/10366/169589 [ES] La agricultura es un sector fundamental en el mundo, destacando los cereales como el grupo de cultivos más relevante. En este contexto, los sistemas de secano adquieren especial importancia, ya que representan la mayor parte de las tierras cultivadas. Sin embargo, la alta vulnerabilidad climática de estos sistemas plantea desafíos importantes, especialmente en regiones como la mediterránea, reconocida como una de las zonas más sensibles al cambio climático global. La humedad del suelo (soil moisture, SM) es una variable crucial en esta región, ya que constituye el principal factor limitante que influye directamente en procesos hidrológicos, fenológicos y productivos. Además, es determinante en la caracterización de fenómenos extremos como las sequías agrícolas, cuya incidencia afecta de forma inmediata al rendimiento de los cultivos y compromete la seguridad alimentaria. Dentro de estos fenómenos, las sequías repentinas (flash droughts, FD) caracterizadas por su rápida intensificación, han generado un creciente interés en los últimos años, ya que representan una amenaza cada vez mayor para los cultivos. A pesar del reconocimiento generalizado de la influencia de la SM en la productividad agrícola y su importancia para la identificación de las sequías, su utilización como indicador en estudios de impacto sobre los cultivos es limitada. Su escasa utilización, junto con la falta de una aplicación específica en áreas vulnerables y en vegetación de interés agronómico, evidencia la necesidad de avanzar hacia investigaciones que aborden de manera integral los efectos del estrés hídrico en la agricultura. Partiendo de esta hipótesis, el objetivo de la presente tesis doctoral fue analizar el impacto de las sequías agrícolas sobre la fenología y la producción del cereal en regiones bajo condiciones mediterráneas. Para lograr este propósito, se plantearon tres objetivos específicos. En primer lugar, se destaca la necesidad de analizar el impacto de la sequía agrícola sobre el rendimiento de los cultivos. A pesar del marcado efecto negativo que los déficits de SM tienen sobre los cultivos, son escasos los estudios que utilizan la SM como variable para identificar este tipo de sequía, a pesar de ser el indicador que la define. En este contexto, el primer objetivo de esta tesis doctoral es analizar y comparar el impacto de la sequía agrícola sobre el rendimiento del trigo y la cebada en las principales regiones cerealistas de España y Alemania, caracterizadas por contrastadas condiciones climáticas, durante el periodo 2001-2020. Para ello, se utilizó la SM de la zona radicular, extraída de la base de datos del modelo LISFLOOD, y se emplearon sus anomalías como índice de sequía agrícola. Además, se identificó el mes en el que la SM ejercía una mayor influencia sobre las variables de estado del cultivo, como la productividad primaria bruta (gross primary productivity, GPP) y el índice de área foliar (leaf area index, LAI), obtenidas del sensor MODIS. Los años de sequía agrícola y su impacto en el rendimiento de los cereales se determinaron mediante tres enfoques basados en el mes crítico, considerando diferentes periodos de análisis. Para identificar dicho mes, se aplicaron dos metodologías diferentes según las condiciones ambientales de cada país. Las variables del cultivo mostraron una dependencia de la SM, especialmente durante los meses de primavera. Asimismo, se observó que las sequías agrícolas provocaron reducciones relevantes en el rendimiento de los cereales, presentando variaciones en su magnitud que reflejan el contraste entre las condiciones ambientales de cada país. Tanto en las regiones tradicionalmente afectadas por las sequías agrícolas, como en aquellas que hasta hace poco no lo estaban, este estudio proporciona información útil para la gestión del agua y la agricultura ante escenarios de cambio climático. En segundo lugar, se partió de la hipótesis de que la evolución temporal de las principales métricas fenológicas antes y después del comienzo del siglo XXI es incierta. Además, la SM raramente se incorpora en los análisis fenológicos basados en teledetección y la mayoría de los estudios se enfocan en la vegetación natural. Por ello, se definió como segundo objetivo de esta tesis doctoral el análisis de los patrones temporales de la fenología de los cereales de secano, extraídos del conjunto de datos GIMMS NDVI3g en las principales regiones cerealistas bajo clima mediterráneo de España, Portugal, Francia e Italia, durante el periodo 1982-2022. Se analizaron por separado las series temporales anteriores y posteriores al inicio del siglo XXI, extrayendo los parámetros fenológicos mediante el método del umbral dinámico modificado, y se estudiaron sus tendencias. Asimismo, se evaluaron las relaciones entre estos parámetros y la influencia de determinadas variables hidroclimáticas sobre el inicio o siembra (start of season, SOS) y el final o cosecha (end of season, EOS) del ciclo fenológico. Las tendencias fenológicas entre ambos periodos de estudio mostraron una inversión temporal coincidente con la pausa del calentamiento global, reflejándose asimismo en la dinámica de la influencia de las variables hidroclimáticas sobre SOS y EOS. Esta información resulta fundamental para la gestión y planificación de los cultivos de secano en escenarios de cambio climático. El último objetivo parte del creciente interés por las FD debido a su dinámica específica, su rápida generación, desarrollo y los daños significativos que ocasionan. No obstante, a pesar de la creciente evidencia de su amenaza para los cultivos, los estudios en ámbitos agrícolas siguen siendo limitados. En este contexto, se planteó como tercer y último objetivo de esta tesis doctoral el análisis de las FD en las principales regiones cerealistas de España, Portugal, Francia e Italia entre 2000 y 2023, evaluando sus efectos sobre la GPP, el rendimiento y la fenología de los cereales. Las FD se identificaron mediante la SM obtenida de la base de datos de reanálisis ERA5-Land. La respuesta de los cereales se analizó mediante dos índices basados en el tiempo de respuesta de la GPP, mientras que el impacto sobre la fenología del cereal se evaluó usando el NDVI (Normalized Difference Vegetation Index), utilizando datos de MODIS. Se observó que las FD afectaron significativamente a los cereales bajo condiciones mediterráneas, presentando mayor frecuencia e intensidad durante los meses críticos de desarrollo, y provocaron un estrés máximo en los cultivos en dichos periodos. Este análisis aporta información clave para entender la resiliencia de los cultivos frente a las FD y para desarrollar estrategias que mitiguen sus efectos en escenarios futuros de cambio climático. 2025-01-01T00:00:00Z http://hdl.handle.net/10366/167322 [ES] El estudio de los hongos y, en particular, de Agaricus bisporus (champiñón de París o champiñón blanco), ha acompañado a la humanidad desde tiempos prehistóricos, atravesando usos rituales, medicinales, culinarios y, en la actualidad, industriales. Esta especie, por su valor nutricional, económico y biotecnológico, es uno de los pilares del cultivo mundial de hongos. El champiñón, es un hongo basidiomiceto ampliamente cultivado y consumido a nivel mundial. Representa una etapa transitoria (el cuerpo fructífero o esporocarpo) de un organismo cuyo ciclo de vida se desarrolla mayormente como una red de filamentos (micelio) que coloniza sustratos orgánicos compostados. Morfológicamente, presenta un sombrero (píleo), láminas (donde se producen las esporas) y un pie (estípite). Es un descomponedor secundario saprofito, especializado en degradar sustratos ricos en lignina y celulosa. El champiñón es un alimento de bajo contenido calórico y rico en proteínas, vitaminas y minerales, con un impacto económico global significativo en la agricultura. Sin embargo, la industria del champiñón se enfrenta a desafíos importantes, como la dependencia en la turba (un recurso no sostenible) como tierra de cobertura, la amenaza constante de enfermedades fúngicas devastadoras como la mole seca (Lecanicillium fungicola), la mole húmeda (Mycogone perniciosa) y la tela de araña (Cladobotryum mycophilum), y un número cada vez más limitado de fungicidas eficaces y permitidos. Además, existe una falta de conocimiento profundo sobre las interacciones hongo (huésped)-hongo (patógeno) a nivel molecular que hace más difícil el desarrollo de nuevas estrategias de control. En este contexto se desarrolla esta tesis, que busca profundizar en la comprensión de la ecología microbiana y las interacciones moleculares subyacentes al cultivo de A. bisporus y su susceptibilidad a las principales enfermedades fúngicas. Al investigar la dinámica de las comunidades microbianas en la cobertura, el impacto de los fungicidas, los cambios en el bacterioma durante la enfermedad y los perfiles transcriptómicos de huésped y patógeno, se busca proporcionar una base científica para desarrollar prácticas de producción mejores, más sostenibles y estrategias de control de enfermedades más efectivas. El capítulo 1 se centra en caracterizar mediante secuenciación de nueva generación (NGS), la estructura de la microbiota (bacteriana y fúngica) de la tierra de cobertura, a base de turba, utilizada en el cultivo de A. bisporus, y cómo esta evoluciona durante la incubación del hongo, así como el efecto de los tratamientos fungicidas clorotalonil y metrafenona. Se observaron cambios estadísticamente significativos en las poblaciones de bacterias y hongos. La composición microbiana se modificó significativamente según el día de incubación, cambiando radicalmente desde las comunidades originales en la materia prima, a una composición microbiana específica impulsada por el crecimiento del micelio de A. bisporus. Los filos bacterianos más dominantes fueron Proteobacteria y Bacteroidota. Se observó un gran cambio en la estructura de las poblaciones bacterianas entre el día 0 y los días siguientes. Las poblaciones de hongos cambiaron más gradualmente, con A. bisporus (familia Agaricaceae, filo Basidiomycota) desplazando al resto de las especies (mayoritariamente del filo Ascomycota inicialmente) a medida que 19 avanzaba el ciclo de cultivo. El tratamiento con clorotalonil, retrasó la colonización de la cobertura por A. bisporus, justificado por una menor proporción de la familia Agaricaceae en las muestras tratadas con este fungicida en comparación con el control y el tratamiento con metrafenona, especialmente en el día 7. Aunque no hubo diferencias significativas en la alfa diversidad entre las comunidades bacterianas entre tratamientos en el día 7, la beta diversidad entre las comunidades fúngicas sí mostró diferencias significativas, sugiriendo un impacto de los fungicidas en la composición general de la comunidad fúngica. Las limitaciones en las bases de datos taxonómicas actuales a menudo no permiten alcanzar una identificación taxonómica a nivel de especie en la mayoría de los casos, lo que restringe la profundidad del análisis.; [EN] The study of fungi, in particular Agaricus bisporus (white button mushroom), has accompanied humanity since prehistoric times, through ritual, medicinal, culinary and, nowadays, industrial uses. This species, due to its nutritional, economic and biotechnological value, is one of the pillars of global mushroom cultivation. The white button mushroom is a basidiomycete fungus that is widely cultivated and consumed worldwide. It represents a transitional stage (the fruiting body or sporocarp) of an organism whose life cycle develops mainly as a network of filaments (mycelium) that colonises composted organic substrates. Morphologically, it has a cap (pileus), gills (where the spores are produced) and a stem (stipe). It is a secondary saprophytic decomposer, specialised in degrading lignin and cellulose rich substrates. Mushrooms are a low-calorie food rich in protein, vitamins and minerals, with a significant global economic impact on agriculture. However, the mushroom industry faces significant challenges, such as dependence on peat (a non-sustainable resource) as casing soil, the constant threat of devastating fungal diseases such as dry bubble (Lecanicillium fungicola), wet bubble (Mycogone perniciosa) and cobweb (Cladobotryum mycophilum), and an increasingly limited number of effective and permitted fungicides. In addition, there is a lack of knowledge about fungus (host)-fungus (pathogen) interactions at the molecular level, which makes it more difficult to develop new control strategies. This thesis was developed in this context and seeks to deepen the understanding of the microbial ecology and molecular interactions underlying the cultivation of A. bisporus and its susceptibility to major fungal diseases. By investigating the dynamics of microbial communities in the casing soil, the impact of fungicides, changes in the bacteriome during disease, and the transcriptomic profiles of host and pathogen, we seek to provide a scientific basis for developing better, more sustainable production practices and more effective disease control strategies. Chapter 1 focuses on characterising, through next-generation sequencing (NGS), the structure of the microbiota (bacterial and fungal) of the peat-based casing soil used in the cultivation of A. bisporus, and how it evolves during the incubation of the fungus, as well as the effect of the fungicide treatments chlorothalonil and metrafenone. Statistically significant changes in bacterial and fungal populations were observed. The microbial composition changed significantly depending on the day of incubation, changing radically from the original communities in the raw material to a specific microbial composition driven by the growth of A. bisporus mycelium. The most dominant bacterial phyla were Proteobacteria and Bacteroidota. A major change in the structure of bacterial populations was observed between day 0 and the following days. Fungal populations changed more gradually, with A. bisporus (family Agaricaceae, phylum Basidiomycota) displacing the rest of the species (initially mainly from the phylum Ascomycota) as the cultivation cycle progressed. Treatment with chlorothalonil delayed the colonisation of the casing soil by A. bisporus, justified by a lower proportion of the Agaricaceae family in the samples treated with this fungicide compared to the control and treatment with metrafenone, especially on day 7. Although there were no significant differences in alpha diversity between bacterial communities between treatments on day 7, beta diversity between fungal communities did show significant differences, suggesting an impact of fungicides on the overall composition of the fungal community. Limitations in current taxonomic databases often do not allow taxonomic identification at the species level in most cases, which restricts the depth of the analysis. 2025-01-01T00:00:00Z http://hdl.handle.net/10366/167240 [EN] Current agriculture needs to find a solution for the dilemma of maintaining high productivity to feed the constantly growing population, but in a sustainable way avoiding the indiscriminate use of agrochemicals. Wheat is one of the most important crops for humankind and its production can be affected by several issues including abiotic stresses such as drought, or fungal diseases as Fusarium head blight (FHB) produced by Fusarium spp., including F. graminearum (Fg). These issues also represent a concern in the actual context of climate change, that could worsen such drought conditions and favour the FHB development. Therefore, new solutions as the use of beneficial microorganisms can be a suitable alternative to agrochemicals. Trichoderma is a fungal genus including species that are of interest to agriculture as direct biological control agents (BCA) against different phytopathogens. Trichoderma spp. are able to mycoparasite other fungi, produce secondary metabolites (SMs) and enzymatic activities with effect on fungi, chromists, bacteria, nematodes or insects, and compete for niche and resources. Moreover, these fungi can establish symbiotic relationships with plants activating their local and systemic defences against biotic and abiotic stresses. This PhD thesis has been focused on the interactions of Trichoderma spp. with wheat plants and pathogens, and on the role played by the hexagonal peroxisome protein 1 gene (hex1) in these relationships; having as main objective the selection of Trichoderma strains susceptible of being applied to wheat crops.; [ES] La agricultura actual necesita encontrar una solución al dilema de mantener una alta productividad para alimentar a una población en constante crecimiento, pero de una forma sostenible, evitando el uso indiscriminado de agroquímicos. El trigo, uno de los cultivos más importantes para la humanidad, y su producción, pueden verse afectados por diversas cuestiones, incluyendo estreses abióticos como la sequía o enfermedades como la fusariosis de la espiga (FHB), producida por especies de Fusarium, incluyendo F. graminearum (Fg). Estas cuestiones representan también una preocupación en un contexto de cambio climático, el cual podría agravar las condiciones de sequía y favorecer el desarrollo de la FHB. Por lo tanto, nuevas soluciones como el uso de microorganismos beneficiosos puede ser una alternativa adecuada a los agroquímicos. Trichoderma es un género fúngico que incluye especies usadas como agentes de control biológico (BCA) frente a diferentes fitopatógenos de interés agrícola. Las especies de Trichoderma son capaces de micoparasitar otros hongos, producir metabolitos secundarios (SMs) y actividades enzimáticas con efecto sobre hongos, cromistas, bacterias, nematodos o insectos, y competir por el nicho y los recursos. Además, Trichoderma puede establecer relaciones simbióticas con la planta, activando sus defensas locales y sistémicas frente a estreses bióticos y abióticos. Esta Tesis Doctoral se centró en las interacciones de Trichoderma con plantas de trigo y patógenos, y en el papel que desempeña el gen de la proteína hexagonal del peroxisoma 1 (hex1) en estas relaciones; teniendo como objetivo principal la selección de cepas de Trichoderma susceptibles de ser aplicadas en el cultivo del trigo. 2025-01-01T00:00:00Z http://hdl.handle.net/10366/166866 [EN] Colletotrichum truncatum, the predominant fungal species associated with soybean anthracnose, is responsible for significant losses in this crop. Chemical control via fungicide application is the most effective strategy for the control of soybean foliar diseases. However, the increasing incidence of anthracnose in some regions of Brazil indicates that current chemical control is not effective against anthracnose. In this study, we evaluated the fungicide sensitivity of C. truncatum genetic lineages to the fungicides azoxystrobin, thiophanate-methyl, difenoconazole, and fludioxonil using isolates representing two important regions of soybean production in Brazil. We characterized the molecular resistance to the quinone-outside inhibitors (QoI), methyl benzimidazole carbamates (MBC), and demethylation inhibitor (DMI) fungicide groups based on amino acid sequences of the cytochrome b (cytb), β-tubulin gene (β-tub), and P450 sterol 14a-demethylases (CYP51) genes. Multiple resistance of C. truncatum isolates to QoI and MBC was observed associated with mutation points in the β-tub (E198A and F200Y) and cytb (G143A). Alternatively, low EC50 values were found for fludioxonil and difenoconazole indicating high efficacy. Analysis of C. truncatum genomes revealed two potential DMI targets, CYP51A and CYP51B, and higher genetic variability in the CYP51A gene. A positive correlation was found between genetic differentiation of C. truncatum populations and fungicide sensitivity (Student's t-test <0.001). To our knowledge, this is the first report of multiple resistance to QoI and MBC fungicides in C. truncatum in Brazil. 2024-01-01T00:00:00Z http://hdl.handle.net/10366/165826 [ES]Existe una gran variedad de microorganismos (bacterias, arqueas, hongos, protistas, etc.) que han sido encontrados en prácticamente todos los ambientes de la Tierra, desde suelos y océanos hasta ambientes extremos como fuentes termales y zonas polares (Amri et al., 2023; Malesevic et al., 2023; Ordóñez-Enireb et al., 2022; Romanenko et al., 2023). Todos ellos juegan un papel importante en la sostenibilidad del ecosistema en el que están presentes mediante diferentes roles. Algunos participan en el ciclo de los nutrientes; ya sea descomponiendo materia orgánica, liberando nutrientes esenciales como nitrógeno, fósforo y carbono, que son reutilizados por otras formas de vida (Pelikan et al., 2021); o mediante la fijación de nitrógeno atmosférico, convirtiendo éste en formas utilizables por las plantas, un proceso crucial para la productividad agrícola y la salud del ecosistema (Sun et al., 2021a). 2024-01-01T00:00:00Z http://hdl.handle.net/10366/163782 [ES]La dormición es la incapacidad de semillas viables para germinar en condiciones favorables. Ventajas: Supervivencia de la planta y adaptación a cambios ambientales. Desventajas en agricultura: Variación en el tiempo de germinación. Reguladores clave: Ácido abscísico (ABA) y DOG1, que afectan la dormición. El óxido nítrico (NO) promueve la germinación y contrarresta el ABA. Se estudia la interacción entre NO y DOG1 para entender la regulación de la dormición. 2024-12-01T00:00:00Z http://hdl.handle.net/10366/161334 The National Aeronautics and Space Administration Soil Moisture Active Passive (SMAP) mission has been validating its soil moisture (SM) products since the start of data production on March 31, 2015. Prior to launch, the mission defined a set of criteria for core validation sites (CVS) that enable the testing of the key mission SM accuracy requirement (unbiased root-meansquare error<0.04 m3/m3). The validation approach also includes other (“sparse network”) in situ SM measurements, satellite SM products, model-based SM products, and field experiments. Over the past six years, the SMAP SM products have been analyzed with respect to these reference data, and the analysis approaches themselves have been scrutinized in an effort to best understand the products’ performance. Validation of the most recent SMAP Level 2 and 3 SM retrieval products (R17000) shows that the L-band (1.4 GHz) radiometer-based SM record continues to meet mission requirements. The products are generally consistent with SM retrievals from the European Space Agency Soil Moisture Ocean Salinity mission, although there are differences in some regions.The high-resolution (3-km) SM retrieval product, generated by combining Copernicus Sentinel-1 data with SMAP observations,performs within expectations. Currently, however, there is limited availability of 3-km CVS data to support extensive validation at this spatial scale. The most recent (version 5) SMAP Level 4 SM data assimilation product providing surface and root-zoneSMwith complete spatio–temporal coverage at 9-km resolution also meets performance requirements. The SMAP SM validation program will continue throughout the mission life; future plans include expanding it to forested and high-latitude regions. 2022-11-02T00:00:00Z http://hdl.handle.net/10366/160846 [EN] Soil moisture (SM) plays a key role in the water cycle, and its variability is intimately linked to coupled landatmosphere processes. Having a good knowledge of soil-atmospheric interactions is thus essential to assess the impact of climate change on SM; however,many aspects of howwater and energy exchanges occur in the soil-atmosphere continuum are still uncertain. In particular, it is known that atmospheric circulation patterns influence climate conditions over Europe but their impact on SM has only rarely been studied. This study provides insight into how atmospheric patterns influence soil moisture dynamics in Europe, where an increase in temperature and agricultural droughts are expected as an impact of climate change. To do so, we analysed the influence of the North Atlantic Oscillation (NAO), the Arctic Oscillation (AO), and the El Niño Southern Oscillation (ENSO) on European SM, including lagged responses, for the period 1991–2020 at a monthly scale. Two methods have been used: a lagged correlation analysis and a more sophisticated causality approach using the PCMCI (PC method combined with themomentary conditional independence (MCI) test). SMseries fromtwo different databases were considered: the hydrological model LISFLOOD and the reanalysis dataset ERA5-Land. The results from the correlation analysis showed a significant, predominantly negative relationships of SM with NAO and AO over almost all of Europe and no significant relation with ENSO. With the causality analysis, similar patterns are obtained for NAO and AO; however, the PCMCI analysis revealed clear patterns of ENSO influencing SM with a delayed response of one-to-two months in central and northwest Europe. The results obtained in this work highlight that there are causal relations between the main modes of interannual climate oscillations and SM variations in Europe, underlining the importance of accounting for global atmospheric circulations to study current changes in regional soil water-related processes 2022-01-01T00:00:00Z http://hdl.handle.net/10366/160651 [EN]Study region: The Henares River Basin, central part of Spain Study focus: An assessment of SWAT soil moisture in a basin under Mediterranean conditions was carried out for the first time. Intercomparison analysis was performed using modeling (LISFLOOD model) and remote sensing (Soil Moisture and Ocean Salinity, SMOS; and Soil Moisture Active Passive, SMAP) products as references, both in the topsoil and in the root zone layers. The analysis was carried out considering both the temporal and the spatial domains. New hydrological insights for the region: The evaluation results, despite being slightly better for the root zone layer, were very good overall in terms of the correlation coefficient, centered root mean square difference, and bias. The SWAT soil moisture product obtained in a basin under Mediterranean conditions gave satisfactory performances, similar to those of the modelling and satellite products with which it has been compared. When analyzing whether these assessment results were determined by factors such as land cover, soil characteristics (texture), topography (slope and altitude) and climate (precipitation), no pattern was observed. There was also no temporal pattern in the quality of the SWAT soil moisture estimation under Mediterranean conditions. Producing reliable SWAT soil moisture databases for different environments around the world, offers the possibility of increasing the availability of suitable soil moisture series, for which there is great interest. 2023-06-28T00:00:00Z http://hdl.handle.net/10366/160650 [EN]Rainfed cereal yields show high variability depending on the varying conditions of concurrent factors during the crop year. Among them, hydrometeorological factors such as maximum temperature, rainfall, and notably, soil moisture, strongly affect crop production, but the greatest source of uncertainty on yield estimates stems from their interaction. This is of special interest in water-limited regions where climate change is expected to affect more intensely, but also in others where water is increasingly limited. Despite the highly non-linear nature of the interactions, simple statistic models such as multilinear regression accurately explore a notable proportion of the variability of cereal yields. To describe the impacts behind interactions, we perform stepwise multilinear regression of meteorological factors derived from E-OBSv23 database and soil moisture from ERA5-Land against annual wheat and barley yields for the period 1981–2019 in the main cereal regions of Spain. The multivariate approach characterizes the temporal shifts of factors’ influence. Beyond the temporal shifts on the synchrony of the factors, some of them tend to co-dominate the impact during the critical period of crop development, with soil moisture exceeding all others in relevance. Multivariate analysis fosters discussion about the impact of the choice of variables on the model fit, as well as on the pertinence of monthly and annual scales for explorative and predictive purposes. Monthly models perform particularly well during the critical period of growth and reproduction of crops and consistently better than univariate estimates. The annual model built using the data of the months of maximum impact of key variables outperforms the model at a monthly scale, which underlines the decisive role of the critical period. Similarly, results highlight the worth of parsimony in modelling. Soil moisture stands out as the principal concurrent variable to improve yield estimates from environmental data, which governs yields of rainfed water-limited croplands. 2023-03-27T00:00:00Z http://hdl.handle.net/10366/160649 [EN]In this research, the active, passive and combined Climate Change Initiative (CCI) Soil Moisture (SM) products were evaluated in comparison with in situ SM measurements from five networks in Spain that have different spatial and temporal scales, densities and environmental conditions. Three of these networks, namely Rinconada, Morille and the Soil Moisture Measurement Stations Network of the University of Salamanca (REMEDHUS), are small- to medium-scale networks and have high station densities, whereas the other two (Inforiego and FluxNet) are sparse and large-scale networks. The results of the comparisons with the former v02.2 version (before the inclusion of the SM retrieved by the Soil Moisture and Ocean Salinity mission, SMOS, in the CCI dataset) showed that the combined CCI performed better than the active or passive, affording correlation coefficients (R) above 0.8 and errors between 0.03 and 0.08 m3 m−3 for the area-average, with biases close to zero. Regarding the land uses and environmental conditions, the stations that were located in the agricultural areas and some forested areas showed the best results, and those that were located in pasture and certain specific agricultural locations showed the poorest results. To test the opportunity of including SMOS in CCI, both datasets were compared over the same areas and coincident periods. After the results, the combined CCI and SMOS SM products matched very well (R=0.83 on average), although the SMOS and CCI under- and overestimate the ground soil moisture measurements, respectively. Finally, the new version of the combined CCI (v03.2, after including SMOS) showed similar correlations to the previous one, but it significantly reduced the bias, leading to slightly lower errors (RMSD and cRMSD). Hence, it was shown that including SMOS in the CCI database enhanced its performance. The results in this work may improve knowledge of the CCI SM and its potential applications. 2019-04-24T00:00:00Z http://hdl.handle.net/10366/160648 [EN]In this study, the ability of satellite soil moisture to track tree growth is analyzed. Despite the reticence of using satellite soil moisture data in forest areas, there is evidence that in some cases, good and reliable results have been obtained. Forests cover very important continental areas and have great importance in many natural processes related to water resources, biodiversity and climate. For these reasons, it is interesting to investigate the applicability of remote sensing soil moisture products for new applications in these environments. In the present study, the CCI (Climate Change Initiative, Global Monitoring of Essential Climate Variables, European Space Agency) soil moisture (CCISM) database has been correlated with the tree-growth series of 22 samples of Aleppo pine (Pinus halepensis Mill.) in Spain in different locations and environmental conditions. Aleppo pine is the most widespread pine species in the Mediterranean basin, and therefore, it is highly representative of the bioclimatic conditions in these water-limited environments. The series spans from 1978 to 2016, and the daily CCISM has been correlated with the annual tree-growth anomalies. The daily CCISM has been obtained using a moving window scheme with 1-, 7-, 15- and 30-day averages, starting on October 1st of the previous year and finishing on December 31st of the corresponding year. Another soil moisture product (Lisflood model) and precipitation have also been used in a similar approach to strengthen the assessment analysis. The results obtained show a clear temporal pattern of the relationship between satellite soil moisture and Aleppo pine tree growth, and the influence of soil moisture on tree-growth dynamics increases with reduced water availability. The CCISM was able to detect a bimodal pattern of tree growth with a maximum in May and a secondary peak in autumn. This temporal pattern was much clearer than that obtained using the modeled soil moisture and the precipitation. This study proves that satellite soil moisture is sensitive enough to track the phenology of this forest species. The results obtained demonstrate that satellite soil moisture data could be suitable for use in forest environments and for new applications. 2019-10-31T00:00:00Z http://hdl.handle.net/10366/160647 [EN]It is of primary interest to determine the extent that natural processes are linked to understand natural system dynamics. There is growing interest in investigating the coupling and coevolution occurring between natural processes and the interaction between natural systems. Soil moisture is a variable that is at the core of the interaction between multiple physical and biological processes; therefore, it is very important to understand the influence of soil moisture dynamics on that coevolution. Soil moisture memory (SMM) shows soil moisture dynamics and the nature of their interaction with other related processes. Several studies have recognized that SMM depends on soil properties and some other meteorological andbiophysical variables; however, there has not been a study specifically devoted to studying the relationshipbetween SMM and the main soil properties. The present study analyzes the relationship between several relevant soil properties (texture, bulk density and organic matter content) involved in soil water dynamics and the stored precipitation fraction (Fp) as a suitable expression of the SMM. The relationship between SMM and precipitation and soil water content was also analyzed. These relationships were analyzed both at the surface layer and at several soil layer depths and with four soil moisture sampling frequencies (3 and 12 h, and 1 and 3 days). The study was conducted with data collected over a period of 12 years, at two soil moisture monitoring networks (REMEDHUS and SCAN) located in Spain and the USA, respectively, covering a wide range of soil characteristics and environmental conditions. The results showed that soil texture plays the main role in understanding SMM dynamics and that organic matter content has a good relationship with Fp. The sand fraction is the variable more correlated with Fp, with a clear inverse relationship (correlation coefficient, from -0.62 to -0.92 in REMEDHUS, and from -0.65 to -0.76 in SCAN). The variations in Fp observed with the different soil layer depths are also mainly correlated with texture and organic matter content, but only for sampling intervals of 1 and 3 days. The temporal variability of Fp in the different soil layers is more correlated with the soil water content than with annual precipitation, especially in the surface layer. At 0–5 depth, R ranges between 0.42 and 0.82. For sampling intervals of 1 and 3 days, the R values between Fp and mean soil moisture are always significant (p < 0.01) and higher than 0.66 in all soil layers. Therefore, in view of the cases studied and the results obtained, the most critical aspect of understanding SMM dynamics is precise characterization of the water storage conditions, especially in terms of texture and organic matter content. 2021-01-25T00:00:00Z http://hdl.handle.net/10366/160646 [EN]Soil moisture (SM) plays a key role in the water cycle, and its variability is intimately linked to coupled landatmosphere processes. Having a good knowledge of soil-atmospheric interactions is thus essential to assess the impact of climate change onSM; however,many aspects of howwater and energy exchanges occur in the soil-atmosphere continuum are still uncertain. In particular, it is known that atmospheric circulation patterns influence climate conditions over Europe but their impact on SM has only rarely been studied. This study provides insight into how atmospheric patterns influence soil moisture dynamics in Europe, where an increase in temperature and agricultural droughts are expected as an impact of climate change. To do so, we analysed the influence of the North Atlantic Oscillation (NAO), the Arctic Oscillation (AO), and the El Niño Southern Oscillation (ENSO) on European SM, including lagged responses, for the period 1991–2020 at a monthly scale. Two methods have been used: a lagged correlation analysis and a more sophisticated causality approach using the PCMCI (PC method combined with the momentary conditional independence (MCI) test). SM series from two different databases were considered: the hydrological model LISFLOOD and the reanalysis dataset ERA5-Land. The results from the correlation analysis showed a significant, predominantly negative relationships of SM with NAO and AO over almost all of Europe and no significant relation with ENSO. With the causality analysis, similar patterns are obtained for NAO and AO; however, the PCMCI analysis revealed clear patterns of ENSO influencing SM with a delayed response of one-to-two months in central and northwest Europe. The results obtained in this work highlight that there are causal relations between the main modes of interannual climate oscillations and SM variations in Europe, underlining the importance of accounting for global atmospheric circulations to study current changes in regional soil water-related processes. 2022-07-22T00:00:00Z