Person:
González García, Esther

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https://academica-e.unavarra.es/handle/2454/49176

Last Name

González García

First Name

Esther

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Ciencias

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IMAB. Research Institute for Multidisciplinary Applied Biology

ORCID

0000-0002-1379-9398

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1764

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Now showing 1 - 10 of 13

Open Access
Physiological responses of legume nodules to drought
(Global Science Books, 2011) Arrese-Igor Sánchez, César; González García, Esther; Marino Bilbao, Daniel; Ladrera Fernández, Rubén; Larrainzar Rodríguez, Estíbaliz; Gil Quintana, Erena; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
Legumes include important agricultural crops, as their high protein content is of primary importance for human food and animal feed. In addition, the ability of most of them to establish symbiotic relationships with soil bacteria allows them to obtain their N requirements from nitrogen fixation in nodules and, therefore, avoids the use of nitrogen fertilizers. Thus, legumes are also essential to improve the soil fertility and quality of agricultural lands and to reclaim eroded or barren areas, making them crucial for agricultural and environmental sustainability. However, legume nitrogen fixation in crop species is very sensitive to environmental constraints and drought, in particular. The present contribution reviews our current knowledge on the processes involved in this inhibition, with particular emphasis on oxygen, nitrogen and carbon physiology. Emerging aspects such as oxidative damage, C/N interactions and sulphur metabolism together with future prospects are also discussed.
Open Access
Physiological and biochemical characterization of rootlets response to salt stress in two Medicago truncatula Gaertn. ecotypes
(Japanese Society for Root Research, 2018) Amouri, Adel Amar; González García, Esther; Aoul, Seghir Hadjadj; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
Legumes are very important plants both ecologically and agriculturally because they are able to interact symbiotically with rhizobia for biological nitrogen fixation and soil fertilization. Medicago truncatula Gaertn. is an important model legume rich in protein. Salinity represents, today, the major cause of land degradation and crop productivity limitation around the world and affects physiology and metabolism in legumes. In this study, we analyzed the physiological and biochemical responses of rootlets in two contrasting ecotypes of Medicago truncatula (Tru 131, tolerant and Jemalong, sensitive) to different level of NaCl, (68, 102 and 137 mM). Results showed that the tolerant ecotype has a lower water potential than Jemalong. Root protein content of Tru 131 was decreased than Jemalong, this can be explained by accumulation of protein oxidation in the sensitive genotype. Moreover, NaCl increased guaiacol peroxidase activity GPX in rootlets of Tru 131, this enzyme has a protective role against the molecules ROS accumulated during oxidative stress. On the other hand, under salt stress the total content of ascorbate (ASC + DHA) and Glutathione (GSH + GSSG) was increased in the tolerant genotype Tru 131 compared to Jemalong. These results show how the tolerant genotype activate the antioxidative defense system at root level against damages caused by oxidative stress under salinity.
Open Access
Local inhibition of nitrogen fixation and nodule metabolism in drought-stressed soybean
(Oxford University Press, 2013) Gil Quintana, Erena; Larrainzar Rodríguez, Estíbaliz; Seminario Huárriz, Amaia; Díaz Leal, Juan Luis; Alamillo, Josefa M.; Pineda, Manuel; Arrese-Igor Sánchez, César; Wienkoop, Stefanie; González García, Esther; Ciencias del Medio Natural; Natura Ingurunearen Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa: 735/2008; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa: 134/2012
Drought stress is a major factor limiting symbiotic nitrogen fixation (NF) in soybean crop production. However, the regulatory mechanisms involved in this inhibition are still controversial. Soybean plants were symbiotically grown in a split-root system (SRS), which allowed for half of the root system to be irrigated at field capacity while the other half remained water deprived. NF declined in the water-deprived root system while nitrogenase activity was maintained at control values in the well-watered half. Concomitantly, amino acids and ureides accumulated in the water-deprived belowground organs regardless of transpiration rates. Ureide accumulation was found to be related to the decline in their degradation activities rather than increased biosynthesis. Finally, proteomic analysis suggests that plant carbon metabolism, protein synthesis, amino acid metabolism, and cell growth are among the processes most altered in soybean nodules under drought stress. Results presented here support the hypothesis of a local regulation of NF taking place in soybean and downplay the role of ureides in the inhibition of NF
Open Access
Is N-feedback involved in the inhibition of nitrogen fixation in drought-stressed Medicago truncatula?
(Oxford University Press, 2013) Gil Quintana, Erena; Larrainzar Rodríguez, Estíbaliz; Arrese-Igor Sánchez, César; González García, Esther; Ciencias del Medio Natural; Natura Ingurunearen Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa: 735/2008
Drought stress is a major factor limiting nitrogen fixation (NF) in crop production. However, the regulatory mechanism involved and the origin of the inhibition, whether local or systemic, is still controversial and so far scarcely studied in temperate forage legumes. Medicago truncatula plants were symbiotically grown with a split-root system and exposed to gradual water deprivation. Physiological parameters, NF activity, and amino acid content were measured. The partial drought treatment inhibited NF in the nodules directly exposed to drought stress. Concomitantly, in the droughted below-ground organs, amino acids accumulated prior to any drop in evapotranspiration (ET). It is concluded that drought exerts a local inhibition of NF and drives an overall accumulation of amino acids in diverse plant organs which is independent of the decrease in ET. The general increase in the majority of single amino acids in the whole plant questions the commonly accepted concept of a single amino acid acting as an N-feedback signal.
Open Access
Nodule carbohydrate catabolism is enhanced in the Medicago truncatula A17-Sinorhizobium medicae WSM419 symbiosis
(Frontiers Media, 2014) Larrainzar Rodríguez, Estíbaliz; Gil Quintana, Erena; Seminario Huárriz, Amaia; Arrese-Igor Sánchez, César; González García, Esther; Ciencias del Medio Natural; Natura Ingurunearen Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The symbiotic association between Medicago truncatula and Sinorhizobium meliloti is a well-established model system in the legume–Rhizobium community. Despite its wide use, the symbiotic efficiency of this model has been recently questioned and an alternative microsymbiont, S. medicae, has been proposed. However, little is known about the physiological mechanisms behind the higher symbiotic efficiency of S. medicae WSM419. In the present study, we inoculated M. truncatula Jemalong A17 with either S. medicae WSM419 or S. meliloti 2011 and compared plant growth, photosynthesis, N2-fixation rates, and plant nodule carbon and nitrogen metabolic activities in the two systems. M. truncatula plants in symbiosis with S. medicae showed increased biomass and photosynthesis rates per plant. Plants grown in symbiosis with S. medicae WSM419 also showed higher N2-fixation rates, which were correlated with a larger nodule biomass, while nodule number was similar in both systems. In terms of plant nodule metabolism, M. truncatula–S. medicae WSM419 nodules showed increased sucrose-catabolic activity, mostly associated with sucrose synthase, accompanied by a reduced starch content, whereas nitrogen-assimilation activities were comparable to those measured in nodules infected with S. meliloti 2011. Taken together, these results suggest that S. medicae WSM419 is able to enhance plant carbon catabolism in M. truncatula nodules, which allows for the maintaining of high symbiotic N2-fixation rates, better growth and improved general plant performance.
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 Publikoa
Root 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.
Open Access
Estudio de prospectiva, análisis y propuesta de participación y colaboración de la Administración Foral de Navarra con las redes, plataformas e iniciativas de ciencia ciudadana
(2016) González García, Esther; Peralta de Andrés, Francisco Javier; Imbert Rodríguez, Bosco; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
El objetivo de este trabajo es analizar las redes y plataformas de ciencia ciudadana existentes con el fin de realizar una propuesta para su implementación en Navarra por parte de la Administración Ambiental; para ello se revisa cómo abordan otras administraciones la ciencia ciudadana a distintos niveles y las posibles formas de participación o colaboración de la Administración.
Open Access
Long-term mannitol-induced osmotic stress leads to stomatal closure, carbohydrate accumulation and changes in leaf elasticity in Phaselous vulgaris leaves
(Academic Journals, 2010) Sassi, Sameh; Aydi, Samir; Hessini, Kamel; González García, Esther; Arrese-Igor Sánchez, César; Abdelly, Chedly; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
The effect of long-term osmotic stress was investigated in leaves of two common bean lines, with contrasting tolerance: Flamingo (tolerant) and coco blanc (sensitive). Water relations, organic solute, ion accumulation and amino acids content as well as osmotic adjustment (OA) were studied during an extended exposure to osmotic stress. Osmotic stress was applied by means of 50 mM mannitol for 15 days. At the end of the stress period, both osmotic potential at full turgor (psi(100)) and at turgor loss point (psi(0)) decreased significantly in stressed plants compared with the control. The decrease being greater in the sensitive line, showed a greater OA compared with flamingo. Sugars contents increased in stressed plants and seem to be the major components of osmotic adjustment in stressed common bean leaves. The increase was more marked in coco blanc. Osmotic stress tolerance could thus not be associated with higher OA. The possible role of decreased leaf cell elasticity (epsilon(max)) is discussed in relation to osmotic stress tolerance in this species.
Open Access
Drought stress provokes the down-regulation of methionine and ethylene biosynthesis pathways in Medicago truncatula roots and nodules
(Wiley, 2014) Larrainzar Rodríguez, Estíbaliz; Molenaar, Johanna A.; Wienkoop, Stefanie; Gil Quintana, Erena; Alibert, Bénédicte; Limami, Anis M.; Arrese-Igor Sánchez, César; González García, Esther; Ciencias del Medio Natural; Natura Ingurunearen Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 735/2008
Symbiotic nitrogen fixation is one of the first physiological processes inhibited in legume plants under water-deficit conditions. Despite the progress made in the last decades, the molecular mechanisms behind this regulation are not fully understood yet. Recent proteomic work carried out in the model legume Medicago truncatula provided the first indications of a possible involvement of nodule methionine (Met) biosynthesis and related pathways in response to waterdeficit conditions. To better understand this involvement, the drought-induced changes in expression and content of enzymes involved in the biosynthesis of Met, S-adenosyl-Lmethionine (SAM) and ethylene in M. truncatula root and nodules were analyzed using targeted approaches. Nitrogenfixing plants were subjected to a progressive water deficit and a subsequent recovery period. Besides the physiological characterization of the plants,the content of total sulphur,sulphate and main S-containing metabolites was measured. Results presented here show that S availability is not a limiting factor in the drought-induced decline of nitrogen fixation rates in M. truncatula plants and provide evidences for a downregulation of the Met and ethylene biosynthesis pathways in roots and nodules in response to water-deficit conditions.
Open Access
Split‐root systems applied to the study of the legume‐rhizobial symbiosis: what have we learned?
(Wiley, 2014) Larrainzar Rodríguez, Estíbaliz; Gil Quintana, Erena; Arrese-Igor Sánchez, César; González García, Esther; Marino Bilbao, Daniel; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
Split-root system (SRS) approaches allow the differential treatment of separate and independent root systems, while sharing a common aerial part. As such, SRS is a useful tool for the discrimination of systemic (shoot origin) versus local (root/nodule origin) regulation mechanisms. This type of approach is particularly useful when studying the complex regulatory mechanisms governing the symbiosis established between legumes and Rhizobium bacteria. The current work provides an overview of the main insights gained from the application of SRS approaches to understand how nodule number (nodulation autoregulation) and nitrogen fixation are controlled both under non-stressful conditions and in response to a variety of stresses. Nodule number appears to be mainly controlled at the systemic level through a signal which is produced by nodule/root tissue, translocated to the shoot, and transmitted back to the root system, involving shoot Leu-rich repeat receptor-like kinases. In contrast, both local and systemic mechanisms have been shown to operate for the regulation of nitrogenase activity in nodules. Under drought and heavy metal stress, the regulation is mostly local, whereas the application of exogenous nitrogen seems to exert a regulation of nitrogen fixation both at the local and systemic levels.