Open Access
Proyecto río Arga: ciencia ciudadana, biodiversidad & educación
(2022) González García, Esther; Peralta de Andrés, Francisco Javier; Ciencias; Zientziak; Gobierno de Navarra / Nafarroako Gobernua, CENEDUCA3-2019
El objetivo del proyecto ARGA, desarrollado en la plataforma iNaturalist (https://www.inaturalist.org/projects/arga), es reunir observaciones de las especies presentes en el río Arga a su paso por la Cuenca de Pamplona. Cualquier persona puede participar, aunque en su creación se ha pensado en su utilización principalmente por estudiantes de Enseñanza Secundaria. Este proyecto se lleva a cabo en colaboración con la Mancomunidad de la Comarca de Pamplona a través del programa Mancoeduca, que ofrece actividades de educación ambiental dirigidas a centros de educación secundaria en el entorno del río Arga.
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
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
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
Root system of Medicago sativa and Medicago truncatula: drought effects on carbon metabolism
(Springer, 2021-03-18) Echeverría Obanos, Andrés; González García, Esther; Ciencias; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB
Aims: Here, we assess the differential impact of drought on root carbon metabolism in the widely cultivated alfalfa (Medicago sativa, Ms) and the model legume Medicago truncatula (Mt). Understanding how carbon allocation is regulated under drought stress conditions is a central issue to improving alfalfa productivity under future climate change scenarios. Methods: Alfalfa and Medicago truncatula were compared under water deficit conditions. Root carbon metabolism of the taproot and fibrous roots was analysed. M. truncatula drought tolerance variability was compared to that of alfalfa using six accessions of the Medicago Hapmap project. The prominent taproot is much less developed in M. truncatula than in alfalfa with the former exhibiting an extensive fibrous root system. Results: In both examined Medicago species the taproot contained the major pools of soluble protein, sucrose and pinitol, whereas the major pools of hexoses and carbon metabolism enzymes appeared to be in the fibrous roots. Under water-deficit conditions, the response of M. sativa strongly differed from that of M. truncatula at the root level. Conclusions: Water deficit conditions differentially modulate the root carbon metabolism of M. sativa and M. truncatula. Mt maintained a more active carbon metabolism in the fibRs, as sucrose, myo-inositol and pinitol accumulated to cope with the water deficit (WD). Conversely, the root system of Ms did not accumulate cyclitols and carbon metabolism was more severely affected under water deficit conditions. This differentially exerted control may determine the drought response of these two close relatives.
Open Access
Learning plant biodiversity in nature: the use of the citizen–science platform iNaturalist as a collaborative tool in secondary education
(MDPI, 2021) Echeverría Obanos, Andrés; Ariz Arnedo, Idoia; Moreno Echeverría, Judit; Peralta de Andrés, Francisco Javier; González García, Esther; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB; Ciencias; Gobierno de Navarra / Nafarroako Gobernua, CENEDUCA3/2019
Biodiversity is a concept of great scientific interest and social value studied in different subjects of the secondary education curriculum. Citizen–science programs may contribute to increasing the engagement of students when studying biodiversity. This work aimed to explore the use of the citizen–science platform iNaturalist as a complement of the elaboration of herbaria in an outdoor activity for 4th course 16-year-old students in the Basaula Reserve. The platform iNaturalist was chosen for its suitability to develop collaborative projects in an educational context. The Basaula project was created and 122 students were trained to record plant species in an outdoor activity. A total of 32 species were recorded, among them the most abundant were beech (Fagus sylvatica) and holm oak (Quercus ilex). The students positively evaluated their experience, highlighting its adequacy to record biodiversity data and make a virtual herbarium. Students valued the innovative character of iNaturalist and its usefulness for research but also the opportunity to integrate mobile devices in school education. We concluded that iNaturalist is a valuable tool to carry out collaborative projects dealing with biodiversity in secondary education.
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.
Open Access
Drought stress causes a reduction in the biosynthesis of ascorbic acid in soybean plants
(Frontiers Media, 2017) Seminario Huárriz, Amaia; Song, Li; Zulet González, Amaia; Nguyen, Henry T.; González García, Esther; Larrainzar Rodríguez, Estíbaliz; Ciencias del Medio Natural; Natura Ingurunearen Zientziak; Gobierno de Navarra / Nafarroako Gobernua, 2016/PI013; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 1287/2011
Drought provokes a number of physiological changes in plants including oxidative damage. Ascorbic acid (AsA), also known as vitamin C, is one of the most abundant water-soluble antioxidant compound present in plant tissues. However, little is known on the regulation of AsA biosynthesis under drought stress conditions. In the current work we analyze the effects of water deficit on the biosynthesis of AsA by measuring its content, in vivo biosynthesis and the expression level of genes in the Smirnoff-Wheeler pathway in one of the major legume crop, soybean (Glycine max L. Merr). Since the pathway has not been described in legumes, we first searched for the putative orthologous genes in the soybean genome. We observed a significant genetic redundancy, with multiple genes encoding each step in the pathway. Based on RNA-seq analysis, expression of the complete pathway was detected not only in leaves but also in root tissue. Putative paralogous genes presented differential expression patterns in response to drought, suggesting the existence of functional specialization mechanisms. We found a correlation between the levels of AsA and GalLDH biosynthetic rates in leaves of drought-stressed soybean plants. However, the levels of GalLDH transcripts did not show significant differences under water deficit conditions. Among the other known regulators of the pathway, only the expression of VTC1 genes correlated with the observed decline in AsA in leaves.
Open Access
Insights into the regulation of nitrogen fixation in pea nodules: lessons from drought, abscisic acid and increased photoassimilate availability
(EDP Sciences, 2001) González García, Esther; Gálvez, Loli; Royuela Hernando, Mercedes; Aparicio Tejo, Pedro María; Arrese-Igor Sánchez, César; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
Nitrogen fixation in legume nodules has been shown to be very sensitive to drought and other environmental constraints. It has been widely assumed that this decline in nitrogen fixation was a consequence of an increase in the so-called oxygen diffusion barrier and a subsequent impairment to bacteroid respiration. However, it has been recently shown that nitrogen fixation is highly correlated with nodule sucrose synthase (SS) activity under drought and other environmental stresses. Whether this correlation reflects a causative relationship or not has not been proven yet. The evidence presented here suggests that SS controls nitrogen fixation under mild drought conditions. However, nitrogen fixation cannot be enhanced only by increasing glycolytic flux, as under these conditions nodules become oxygen limited. Abscisic acid also induces a decline in nitrogen fixation that is independent of SS. The overall results suggest the occurrence of a complex regulation of nodule nitrogen fixation involving, at least, both carbohydrate and oxygen fluxes within the nodule.
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.