Person: Castañeda Presa, Verónica
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Castañeda Presa
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Verónica
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Ciencias del Medio Natural
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IMAB. Research Institute for Multidisciplinary Applied Biology
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0000-0001-5773-1988
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810679
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Publication Open Access Medicago truncatula response to water-deficit stress: whole plant perspectives(2021) Castañeda Presa, Verónica; González García, Esther; Ciencias; Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaMedicago truncatula es una planta forrajera anual con gran interés agronómico y científico, siendo de hecho empleada como planta modelo en el estudio de la biología de las leguminosas. Teniendo en cuenta el contexto actual del cambio climático, es de vital importancia mantener o aumentar el rendimiento de los cultivos para así poder responder a los requerimientos derivados del constante aumento de la población mundial. Para ello, es imprescindible entender las res-puestas adaptativas de las plantas al estrés hídrico, siendo muy útil el empleo de esta planta modelo para su estudio. En este trabajo hemos estudiado el comportamiento de varios órganos vegetales con especial énfasis en el sistema radical, permitiéndonos un conocimiento más inte-grado de los mecanismos de respuesta al estrés hídrico a nivel de planta entera. El sistema radical de M. truncatula fue estudiado en el Capítulo 1, en el cual hicimos una distinción entre la raíz primaria, más gruesa, y las raíces laterales o “raíz fibrosa”, mucho más finas. Se estudió entonces el comportamiento de ambos tipos de raíz en condiciones control, remarcando la gran diferencia metabólica entre ambas, teniendo la raíz primaria un papel más activo que como mero almacén de reservas. Además, se observó una mayor resiliencia de la raíz primaria al estrés hídrico, pudiendo tener la modulación de la degradación de la sacarosa y del metabolismo de la prolina un papel esencial en la adaptación del sistema radical al estrés hídrico. En el Capítulo 2 hemos abordado diversos tipos de estrés hídrico, empleando para ello con-diciones iso-osmóticas de salinidad (NaCl y KCl), falta de riego y un agente osmótico (PEG-6000). Esta comparativa nos permite identificar las semejanzas y diferencias en los mecanismos de respuesta a cada estrés a nivel de planta entera. Por un lado, los resultados obtenidos nos llevaron a descartar el uso de PEG como un compuesto apto para semejar condiciones de sequía, mientras que la exposición de M. truncatula a NaCl y KCl provocó respuestas similares, con un ligero mayor efecto negativo en el metabolismo por parte de este último. Al comparar la res-puesta a la falta de riego se observó un mayor énfasis en la protección del sistema radical, mien-tras que la exposición a NaCl conllevó una mayor respuesta a nivel de parte aérea. El estudio del floema nos permitió una mejor comprensión de las respuestas sistémicas de la planta a los di-versos tipos de estrés hídrico. En resumen, este estudio proporciona un mayor conocimiento de la respuesta de M. trunca-tula a condiciones de estrés hídrico a nivel de planta entera y desde un punto de vista bioquí-mico, metabólico y fisiológico.Publication Open Access Ecophysiological roles of abaxial anthocyanins in a perennial understorey herb from temperate deciduous forests(Oxford University Press, 2015) Fernández Marín, Beatriz; Esteban Terradillos, Raquel; Míguez, Fátima; Artetxe, Unai; Castañeda Presa, Verónica; Pintó Marijuan, Marta; Becerril, José María; García Plazaola, José Ignacio; Natura Ingurunearen Zientziak; Ciencias del Medio Natural; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako InstitutuaAccumulation of abaxial anthocyanins is an intriguing leaf trait particularly common among deeply shaded understorey plants of tropical and temperate forests whose ecological significance is still not properly understood. To shed light on it, possible ecophysiological roles of abaxial anthocyanins were tested in the perennial understorey herb of temperate deciduous forests Saxifraga hirsuta, chosen as a model species due to the coexistence of green and anthocyanic leaves and the presence of an easily removable lower anthocyanic epidermis. Anthocyanins accumulated during autumn, which temporally matched the overstorey leaf fall. Patterns of development of abaxial anthocyanins and direct measurements of photochemical efficiency under monochromatic light were not consistent with a photoprotective hypothesis. Enhancement of light capture also seemed unlikely since the back-scattering of red light towards the lower mesophyll was negligible. Seed germination was similar under acyanic and anthocyanic leaves. A relevant consequence of abaxial anthocyanins was the dramatic reduction of light transmission through the leaf. The dark environment generated underneath the Saxifraga canopy was enhanced by the horizontal repositioning of leaves, which occurs in parallel with reddening. This might play a role in biotic interactions by inhibiting vital processes of competitors, which may be of especial importance in spring before the overstorey leaves sprout.Publication Open Access Legume nitrogen utilization under drought stress(Springer, 2018) Castañeda Presa, Verónica; Gil Quintana, Erena; Echeverría Obanos, Andrés; González García, Esther; Ciencias; ZientziakLegumes account for around 27% of the world’s primary crop production and can be classified based on their use and traits into grain and forage legumes. Legumes can establish symbiosis with N-fixing soil bacteria. As a result, a new organ is formed, the nodule, where the reduction of atmospheric N2 into ammonia is carried out catalyzed by the bacterial exclusive enzyme nitrogenase. The process, highly energy demanding, is known as symbiotic nitrogen fixation and provides all the N needs of the plant, thus avoiding the use of N fertilizers in the context of sustainable agriculture. However, legume crops are often grown under non-fixing conditions since legume nodulation is suppressed by high levels of soil nitrogen occurring in chemically fertilized agro-environment. In addition, legumes are very sensitive to environmental stresses, being drought one of the significant constraints affecting crop production. Due to their agricultural and economic importance, scientists have carried out basic and applied research on legumes to better understand responses to abiotic stresses and to further comprehend plant–microbe interactions. An integrated view of nitrogen utilization under drought stress will be presented with particular focus on legume crops.Publication Open Access Functional analysis of the taproot and fibrous roots of Medicago truncatula: sucrose and proline catabolism primary response to water deficit(Elsevier, 2019) Castañeda Presa, Verónica; Peña, Marlon de la; Azcárate Górriz, Lidia; Aranjuelo Michelena, Iker; González García, Esther; Ciencias; Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaRoot performance represents a target factor conditioning plant development under drought conditions. Moreover, recent root phenotyping studies remark relevant differences on functionality of the different root types. However, despite its relevance, the performance of different types of roots such as primary/taproot (tapR) and lateral/fibrous roots (fibR) under water stress conditions is largely unknown. In the current study, the impact of water stress on target C and N metabolism (namely sucrose and proline) processes were characterized in tapR and fibR of Medicago truncatula plants exposed to different water stress severity regimes (moderate versus severe). While both root types exhibit some common responses to face water stress, the study highlighted important physiological and metabolic differences between them. The tapR proved to have an essential role on carbon and nitrogen partitioning rather than just on storage. Moreover, this root type showed a higher resilience towards water deficit stress. Sucrose metabolization at sucrose synthase level was early blocked in this tissue together with a selective accumulation of some amino acids such as proline and branched chain amino adds, which may act as alternative carbon sources under water deficit stress conditions. The decline in respiration, despite the over-accumulation of carbon compounds, suggests a modulation at sucrose cleavage level by sucrose synthase and invertase. These data not only provide new information on the carbon and nitrogen metabolism modulation upon water deficit stress but also on the different role, physiology, and metabolism of the taproot and fibrous roots. In addition, obtained results highlight the fact that both root types show distinct performance under water deficit stress; this factor can be of great relevance to improve breeding programs for increasing root efficiency under adverse conditions.Publication Open Access Strategies to aply water-deficit stress: similarities and disparities at the whole plant metabolism level in medicago truncatula(MDPI, 2021) Castañeda Presa, Verónica; González García, Esther; Ciencias; Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaWater-deficit stresses such as drought and salinity are the most important factors limiting crop productivity. Hence, understanding the plant responses to these stresses is key for the improvement of their tolerance and yield. In this study M. truncatula plants were subjected to 250 mM NaCl as well as reduced irrigation (No-W) and 250 g/L polyethylene glycol (PEG)-6000 to induce salinity and drought stress, respectively, provoking a drop to −1.7 MPa in leaf water potential. The whole plant physiology and metabolism was explored by characterizing the stress responses at root, phloem sap and leaf organ level. PEG treatment led to some typical responses of plants to drought stress, but in addition to PEG uptake, an important impairment of nutrient uptake and a different regulation of carbon metabolism could be observed compared to No-W plants. No-W plants showed an important redistribution of antioxidants and assimilates to the root tissue, with a distinctive increase in root proline degradation and alkaline invertase activity. On the contrary, salinity provoked an increase in leaf starch and isocitrate dehydrogenase activity, suggesting key roles in the plant response to this stress. Overall, results suggest higher protection of salt-stressed shoots and non-irrigated roots through different mechanisms, including the regulation of proline and carbon metabolism, while discarding PEG as safe mimicker of drought. This raises the need to understand the effect at the whole plant level of the different strategies employed to apply water-deficit stress.