Open Access
Potencialidades del frijol caupí para la resiliencia al cambio climático en sistemas agrícolas locales
(2022) Santana-Baños, Yoerlandy; González García, Esther; Ariz Arnedo, Idoia; Carrodeguas Díaz, Sergio; Ciencias; Zientziak
Las evidencias científicas sugieren tres usos fundamentales del frijol caupí, con agro-ecológicas y beneficios productivos, sociales y ambientales en los sistemas agrícolas locales; sin embargo, su rendimiento a nivel mundial y en América no experimenta crecimiento en los últimos años. Los resultados obtenidos en Pinar del Río, Cuba, sugieren la posibilidad de emplearlo como alternativa para la producción de grano pero debe fomentarse, desde la ciencia, la innovación y las instituciones y órganos de decisión a nivel local, la cultura de producción y consumo de esta leguminosa para su aprovechamiento en la sostenibilidad agrícola de los agro-ecosistemas.
Open Access
Plant ammonium sensitivity is associated with external pH adaptation, repertoire of nitrogen transporters, and nitrogen requirement
(Oxford University Press, 2024-03-11) Rivero Marcos, Mikel; Lasa Larrea, Berta; Neves, Tomé; Zamarreño, Ángel M.; García Mina, José M.; García Olaverri, Carmen; Aparicio Tejo, Pedro María; Cruz, Cristina; Ariz Arnedo, Idoia; Ciencias; Zientziak; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika; Institute for Multidisciplinary Research in Applied Biology - IMAB; Institute for Advanced Research in Business and Economics - INARBE; Universidad Publica de Navarra / Nafarroako Unibertsitate Publikoa; Gobierno de Navarra / Nafarroako Gobernua
Modern crops exhibit diverse sensitivities to ammonium as the primary nitrogen source, influenced by environmental factors such as external pH and nutrient availability. Despite its significance, there is currently no systematic classification of plant species based on their ammonium sensitivity. We conducted a meta-analysis of 50 plant species and present a new classification method based on the comparison of fresh biomass obtained under ammonium and nitrate nutrition. The classification uses the natural logarithm of the biomass ratio as the size effect indicator of ammonium sensitivity. This numerical parameter is associated with critical factors for nitrogen demand and form preference, such as Ellenberg indicators and the repertoire of nitrogen transporters for ammonium and nitrate uptake. Finally, a comparative analysis of the developmental and metabolic responses, including hormonal balance, is conducted in two species with divergent ammonium sensitivity values in the classification. Results indicate that nitrate has a key role in counteracting ammonium toxicity in species with a higher abundance of genes encoding NRT2-type proteins and fewer of those encoding the AMT2-type proteins. Additionally, the study demonstrates the reliability of the phytohormone balance and methylglyoxal content as indicators for anticipating ammonium toxicity. This study emphasizes the importance of ecophysiological requirements and the repertoire of nitrogen transporters in understanding plant sensitivity to ammonium, and enhances our knowledge of plant nitrogen nutrition.
Open Access
High irradiance increases NH4+ tolerance in Pisum sativum: higher carbon and energy availability improve ion balance but not N assimilation
(Elsevier, 2011-03-02) Ariz Arnedo, Idoia; Artola Rezola, Ekhiñe; Asensio, Aarón C.; Cruchaga Moso, Saioa; Aparicio Tejo, Pedro María; Morán Juez, José Fernando; Ciencias del Medio Natural; Natura Ingurunearen Zientziak; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Institute for Multidisciplinary Research in Applied Biology - IMAB
The widespread use of NO3− fertilization has had a major ecological impact. NH4+ nutrition may help to reduce this impact, although high NH4+ concentrations are toxic for most plants. The underlying tolerance mechanisms are not yet fully understood, although they are thought to include the limitation of C, the disruption of ion homeostasis, and a wasteful NH4+ influx/efflux cycle that carries an extra energetic cost for root cells. In this study, high irradiance (HI) was found to induce a notable tolerance to NH4+ in the range 2.5–10 mM in pea plants by inducing higher C availability, as shown by carbohydrate content. This capacity was accompanied by a general lower relative N content, indicating that tolerance is not achieved through higher net N assimilation on C-skeletons, and it was also not attributable to increased GS content or activity in roots or leaves. Moreover, HI plants showed higher ATP content and respiration rates. This extra energy availability is related to the internal NH4+ content regulation (probably NH4+ influx/efflux) and to an improvement of the cell ionic balance. The limited C availability at lower irradiance (LI) and high NH4+ resulted in a series of metabolic imbalances, as reflected in a much higher organic acid content, thereby suggesting that the origin of the toxicity in plants cultured at high NH4+ and LI is related to their inability to avoid large-scale accumulation of the NH4+ ion.
Open Access
Depletion of the heaviest stable N isotope is associated with NH4+/NH3 toxicity in NH4+-fed plants
(BioMed Central, 2011) Ariz Arnedo, Idoia; Cruz, Cristina; Morán Juez, José Fernando; González Moro, María Begoña; García Olaverri, Carmen; González Murua, Carmen; Martins Loucao, María A.; Aparicio Tejo, Pedro María; Estatistika eta Ikerketa Operatiboa; Estadística e Investigación Operativa; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
Background: In plants, nitrate (NO3-) nutrition gives rise to a natural N isotopic signature (δ15N), which correlates with the δ15N of the N source. However, little is known about the relationship between the δ15N of the N source and the 14N/15N fractionation in plants under ammonium (NH4+) nutrition. When NH4 + is the major N source, the two forms, NH4 + and NH3, are present in the nutrient solution. There is a 1.025 thermodynamic isotope effect between NH3 (g) and NH4 + (aq) which drives to a different δ15N. Nine plant species with different NH4 +-sensitivities were cultured hydroponically with NO3 - or NH4 + as the sole N sources, and plant growth and δ15N were determined. Short-term NH4 +/NH3 uptake experiments at pH 6.0 and 9.0 (which favours NH3 form) were carried out in order to support and substantiate our hypothesis. N source fractionation throughout the whole plant was interpreted on the basis of the relative transport of NH4 + and NH3. Results: Several NO3 --fed plants were consistently enriched in 15N, whereas plants under NH4 + nutrition were depleted of 15N. It was shown that more sensitive plants to NH4 + toxicity were the most depleted in 15N. In parallel, N-deficient pea and spinach plants fed with 15NH4 + showed an increased level of NH3 uptake at alkaline pH that was related to the 15N depletion of the plant. Tolerant to NH4 + pea plants or sensitive spinach plants showed similar trend on 15N depletion while slight differences in the time kinetics were observed during the initial stages. The use of RbNO3 as control discarded that the differences observed arise from pH detrimental effects. Conclusions: This article proposes that the negative values of δ15N in NH4 +-fed plants are originated from NH3 uptake by plants. Moreover, this depletion of the heavier N isotope is proportional to the NH4 +/NH3 toxicity in plants species. Therefore, we hypothesise that the low affinity transport system for NH4 + may have two components: one that transports N in the molecular form and is associated with fractionation and another that transports N in the ionic form and is not associated with fractionation.
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
Can N nutrition lead to "plant diabetes"? The perspective from ammonium nutrition and methylglyoxal accumulation
(Frontiers Media, 2022) Rivero Marcos, Mikel; Ariz Arnedo, Idoia; Institute for Multidisciplinary Research in Applied Biology - IMAB; Gobierno de Navarra / Nafarroako Gobernua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Here we introduce a debate about whether plants can be suffering a "diabetes-like syndrome" depending on the N nutrition management. The idea of a plant diabetes is not new and was initially proposed by Saito et al. (2011) when they identified MG as a potent photosystem I-mediated superoxides generator in spinach chloroplasts. Later and along the same lines, Takagi et al. (2014) and Shimakawa et al. (2014) discussed the possible plant diabetes by associating it with the accumulation of MG as a common metabolite of the primary pathways of sugar anabolism and catabolism. Nevertheless, given the increasing relevance of NH+ 4 nutrition for crop production in a context of elevated atmospheric CO2, in addition to being a less polluting alternative to the excessive use of NO- 3 (Subbarao and Searchinger, 2021), we examine here from a new point of view the current knowledge about the glycolytic by-product MG and its link to a possible "NH+ 4 diet"-mediated plant diabetes.
Open Access
Effect of N-(n-butyl) thiophosphoric triamide on urea metabolism and the assimilation of ammonium by Triticum aestivum L.
(Springer, 2010-08-25) Artola Rezola, Ekhiñe; Cruchaga Moso, Saioa; Ariz Arnedo, Idoia; Morán Juez, José Fernando; Garnica, María; Houdusse, Fabrice; García Mina, José M.; Irigoyen Iriarte, Ignacio; Lasa Larrea, Berta; Aparicio Tejo, Pedro María; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Producción Agraria; Nekazaritza Ekoizpena
The use of urea as an N fertilizer has increased to such an extent that it is now the most widely used fertilizer in the world. However, N losses as a result of ammonia volatilization lead to a decrease in its efficiency, therefore different methods have been developed over the years to reduce these losses. One of the most recent involves the use of urea combined with urease inhibitors, such as N-(n-butyl) thiophosphoric triamide (NBPT), in an attempt to delay the hydrolysis of urea in the soil. The aim of this study is to perform an in-depth analysis of the effects that NBPT use has on plant growth and N metabolism. Wheat plants were cultivated in a greenhouse experiment lasting four weeks and fertilized with urea and NBPT at different concentrations (0, 0.012, 0.062, 0.125%). Each treatment was replicated six times. A non-fertilized control was also cultivated. Several parameters related with N metabolism were analysed at harvest. NBPT use was found to have visible effects, such as a transitory yellowing of the leaf tips, at the end of the first week of treatment. At a metabolic level, plants treated with the inhibitor were found to have more urea in their tissues and a lower amino acid content, lower glutamine synthetase activity, and lower urease and glutamine synthetase content at the end of the study period, whereas their urease activity seemed to have recovered by this stage.
Open Access
Use of recombinant iron-superoxide dismutase as a marker of nitrative stress
(Elservier, 2008-04-20) Larrainzar Rodríguez, Estíbaliz; Urarte Rodríguez, Estíbaliz; Auzmendi, Iñigo; Ariz Arnedo, Idoia; Arrese-Igor Sánchez, César; González García, Esther; Morán Juez, José Fernando; Ciencias del Medio Natural; Natura Ingurunearen Zientziak; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Gobierno de Navarra / Nafarroako Gobernua, 57/2007
Superoxide dismutases (SODs; EC 1.15.1.1) are a group of metalloenzymes which are essential to protect cells under aerobic conditions. In biological systems, it has been reported that SODs and other proteins are susceptible to be attacked by peroxynitrite (ONOO-) which can be originated from the reaction of nitric oxide with superoxide radical. ONOO- is a strong oxidant molecule capable of nitrating peptides and proteins at the phenyl side chain of the tyrosine residues. In the present work, bovine serum albumin (BSA) and recombinant iron¿superoxide dismutase from the plant cowpea (Vu_FeSOD) are used as target molecules to estimate ONOO- production. The method employs the compound SIN-1, which simultaneously generates -NO and O2- in aerobic aqueous solutions. First, assay conditions were optimized incubating BSA with different concentrations of SIN-1, and at a later stage, the effect on the tyrosine nitration and catalytic activity of Vu_FeSOD was examined by in-gel activity and spectrophotometric assays. Both BSA and Vu_FeSOD are nitrated in a dose-dependent manner, and, at least in BSA nitration, the reaction seems to be metal catalyzed.
Open Access
Foliar application of urea to "Sauvignon Blanc" and "Merlot" vines: doses and time of application
(Springer Nature, 2012-02-19) Lasa Larrea, Berta; Menéndez Villanueva, Sergio; Sagastizabal, Kepa; Calleja Cervantes, María Eréndira; Irigoyen Iriarte, Ignacio; Muro Erreguerena, Julio; Aparicio Tejo, Pedro María; Ariz Arnedo, Idoia; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Producción Agraria; Nekazaritza Ekoizpena
A careful control of the N nutritional status of grapevines can have a determining effect on wine characteristics; therefore a suitable management of N fertilization might allow some wine parameters to be modified, thereby improving product quality. The aim of this study was to determine the effect of foliar application of urea at different doses and different times of the growing season on the parameters of Sauvignon Blanc and Merlot grape juice. The research described herein involved Sauvignon Blanc and Merlot grapevines (V. vinifera L.) at a commercial vineyard and was conducted over 2 years. In the first year, N treatment involved a foliar application at a dose of 10 kg N ha−1 during veraison, whereas in the second year it involved a foliar urea application at two doses (10 and 50 kg N ha−1) and at three different times—3 weeks before veraison, during veraison and 3 weeks after veraison. In this second year, the urea applied at a dose of 10 kg N ha−1 was isotopically labelled with 1% 15N. Chemical parameters, yeast assimilable N, amino acid content, amino acid profile and N isotopic composition were determined for all treatments. Grape and grape-juice parameters for Merlot were found to be more affected by N fertilization than for Sauvignon Blanc and were also more affected during the second year than during the first year, thus indicating that the climatic characteristics of each campaign could affect these parameters. The yeast assimilable N in grape juice was found to be higher for late applications of foliar urea, with application of the higher dose of urea during veraison increasing the amino acid and proline contents in both varieties. The isotopic analysis data showed that the urea applied to leaves was transferred to the berries, with the maximum translocation in Sauvignon Blanc occurring for the post-veraison treatment and in Merlot for the veraison treatment. We can therefore conclude that foliar application of urea could modify grape juice quality and could therefore be used as a tool for obtaining quality wines.
Open Access
Leaf δ15N as a physiological indicator of the responsiveness of N2-fixing alfalfa plants to elevated CO2, temperature and low water availability
(Frontiers Media, 2015) Ariz Arnedo, Idoia; Cruz, Cristina; Neves, Tomé; Irigoyen, Juan J.; García Olaverri, Carmen; Nogués, Salvador; Aparicio Tejo, Pedro María; Aranjuelo Michelena, Iker; Estatistika eta Ikerketa Operatiboa; Natura Ingurunearen Zientziak; Estadística e Investigación Operativa; Ciencias del Medio Natural; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Gobierno de Navarra / Nafarroako Gobernua
The natural 15N/14N isotope composition (δ15N) of a tissue is a consequence of its N source and N physiological mechanisms in response to the environment. It could potentially be used as a tracer of N metabolism in plants under changing environmental conditions, where primary N metabolism may be complex, and losses and gains of N fluctuate over time. In order to test the utility of δ15N as an indicator of plant N status in N2-fixing plants grown under various environmental conditions, alfalfa (Medicago sativa L.) plants were subjected to distinct conditions of [CO2] (400 vs. 700 μmol mol−1), temperature (ambient vs. ambient +4°C) and water availability (fully watered vs. water deficiency—WD). As expected, increased [CO2] and temperature stimulated photosynthetic rates and plant growth, whereas these parameters were negatively affected by WD. The determination of δ15N in leaves, stems, roots, and nodules showed that leaves were the most representative organs of the plant response to increased [CO2] and WD. Depletion of heavier N isotopes in plants grown under higher [CO2] and WD conditions reflected decreased transpiration rates, but could also be related to a higher N demand in leaves, as suggested by the decreased leaf N and total soluble protein (TSP) contents detected at 700 μmol mol−1 [CO2] and WD conditions. In summary, leaf δ15N provides relevant information integrating parameters which condition plant responsiveness (e.g., photosynthesis, TSP, N demand, and water transpiration) to environmental conditions.