Carmen Gonzalez-Murua

Universidad del País Vasco / Euskal Herriko Unibertsitatea | UPV/EHU · Vegetal Biology and Ecology

Agriculture has increased the release of reactive nitrogen to the environment due to crops' low nitrogen-use efficiency (NUE) after the application of nitrogen-fertilisers. Practices like the use of stabilized-fertilisers with nitrification inhibitors such as DMPP (3,4-dimethylpyrazole phosphate) have been adopted to reduce nitrogen losses. Otherwi...

Background The increasing demand for food production has led to a tenfold increase in nitrogen (N) fertilizer use since the Green Revolution. Nowadays, agricultural soils have been turned into high-nitrifying environments that increase N pollution. To decrease N losses, synthetic nitrification inhibitors (SNIs) such as 3,4-dimethylpyrazole phosphat...

Nitrification inhibitors (NIs) are useful tools to reduce nitrogen (N) losses derived from fertilization in agriculture. However, it remains unclear whether a future climate scenario with elevated CO2 could affect NIs efficiency. Thus, the objective of this work was to study whether the increase of atmospheric CO2 concentration would affect the eff...

Nitrogen fertilization is the most important factor increasing nitrous oxide (N2O) emissions from agriculture, which is a powerful greenhouse gas. These emissions are mainly produced by the soil microbial processes of nitrification and denitrification, and the application of nitrification inhibitors (NIs) together with an ammonium-based fertilizer...

Active nitrifiers and rapid nitrification are major contributing factors to nitrogen losses in global wheat production. Suppressing nitrifier activity is an effective strategy to limit N losses from agriculture. Production and release of nitrification inhibitors from plant roots is termed “biological nitrification inhibition” (BNI). Here, we report...

In forest nurseries, intensive use of non-renewable substrates such as peat and high application rates of chemical synthesis fertilizers lead to environmental problems and high susceptibility to biotic and abiotic stresses. This work aims to seek more sustainable crop management to help mitigate these problems, combining the substitution of peat by...

Enhanced-efficiency nitrogen (N) fertilizers, such as those containing nitrification or urease inhibitors, can mitigate the carbon (C) footprint linked to the production of bioenergy crops through a reduction in direct nitrous oxide (N2O) emissions and indirect N2O losses. These indirect emissions are derived from ammonia (NH3) volatilization, whic...

Nitrogen (N) input from fertilizers modifies the properties of agricultural soils as well as bacterial community diversity, composition and relationships. This can lead to negative impacts such as the deterioration of system multifunctionality, whose maintenance is critical to normal nutrient cycling. Synthetic nitrification inhibitors (NIs) can be...

RNA-based high-throughput sequencing is a valuable tool in the discernment of the implication of metabolically active bacteria during composting. In this study, “alperujo” composting was used as microbial model for the elucidation of structure-function relationships with physicochemical transformation of the organic matter. DNA and RNA, subsequentl...

Improving fertilizer nitrogen (N) use efficiency is essential to increase crop productivity and avoid environmental damage. This study was conducted during four crop cycles of winter wheat under humid Mediterranean conditions (Araba, northern Spain). The effects of N-fertilization splitting and the application of the nitrification inhibitors (NIs)...

Urea fertilization is a widely spread source of nitrogen (N) for agriculture because of its easy accessibility. However, its use is highly inefficient, since a large amount of the applied N is lost to the environment mainly in the form of ammonia (NH3) volatilization, causing serious environmental and economic damages. Although there are simple str...

Nitrate and ammonium are the main nitrogen sources in agricultural soils. In the last decade, ammonium (NH4+), a double-sided metabolite, has attracted considerable attention by researchers. Its ubiquitous presence in plant metabolism and its metabolic energy economy for being assimilated contrast with its toxicity when present in high amounts in t...

In agriculture, the applied nitrogen (N) can be lost in the environment in different forms because of microbial transformations. It is of special concern the nitrate (NO3⁻) leaching and the nitrous oxide (N2O) emissions, due to their negative environmental impacts. Nitrification inhibitors (NIs) based on dimethylpyrazole (DMP) are applied worldwide...

Low atmospheric relative humidity (RH) accompanied by elevated air temperature and decreased precipitation are environmental challenges that wheat production will face in future decades. These changes to the atmosphere are causing increases in air vapor pressure deficit (VPD) and low soil water availability during certain periods of the wheat-growi...

The current study focuses on yield and nutritional quality changes of wheat grain over the last 166 years. It is based on wheat grain quality analyses carried out on samples collected between 1850 and 2016. Samples were obtained from the Broadbalk Continuous Wheat Experiment (UK) and from herbaria from 16 different countries around the world. Our s...

This chapter presents a study of nitrous oxide (N2O) emissions from (a) forest soils (Pinus radiata and Fagus sylvatica) at different growth stages and from (b) grassland and agricultural soils in the edapho-climatic conditions of northern Spain. A mixed clover–ryegrass sward, wheat and oats crops were fertilized with ammonium sulphate nitrate, cat...

Anthropogenic heavy metal pollution is an important health issue in urban areas, and therefore rapid and inexpensive monitoring in time and space is desirable. This study aimed (i) to assess the suitability of Tilia cordata leaves as a valuable heavy metal bioindicator, including seasonal changes in concentrations and (ii) to evaluate the use of le...

Nitrogen (N) applied with fertilizers is not efficiently used in agriculture. In the soil, this N is transformed into different compounds by means of several biological processes. As a result, there is a negative economic and environmental impact due to water contamination, via nitrate (NO3−) leaching, and greenhouse gasses emission, via nitrous ox...

Agricultural sustainability is compromised by nitrogen (N) losses caused by soil microbial activity. Nitrous oxide (N2O) is a potent greenhouse gas (GHG) produced as consequence of nitrification and denitrification processes in soils. Nitrification inhibitors (NI) as 3,4-dimethylpyrazole-succinic acid (DMPSA) are useful tools to reduce these N loss...

The Lluta Valley in Northern Chile is an important agricultural area affected by both salinity and boron (B) toxicity. Zea mays L. amylacea, an ecotype arisen because of the seed selection practiced in this valley, shows a high tolerance to salt and B levels. In the present study the interaction between B and salt was studied after 20 days of treat...

Nutrition is one of the factors that most limits forestry plant growth, so current production in nurseries is based on conventional fertilization focused on enhancing vigorous. However, an excessive intake of mineral nitrogen can cause morphological imbalances and the formation of more succulent tissues which consequently increase susceptibility to...

Selection and management of synthetic nitrogen (N) fertilizers, including nitrification inhibitors, is considered an effective strategy to mitigate N oxide emissions, but depends strongly on soil characteristics and climatic conditions. We evaluated the effect of the use of a nitrification inhibitor (2-(3,4-dimethyl-1H-pyrazol-1-yl) succinic acid i...

Proper carbon (C) supply is essential for nitrogen (N) assimilation especially when plants are grown under ammonium (NH4+) nutrition. However, how C and N metabolic fluxes adapt to achieve so remains uncertain. In this work, roots of wheat (Triticum aestivum L.) plants grown under exclusive NH4+ or nitrate (NO3−) supply were incubated with isotope-...

While nitrogen (N) derived from ammonium would be energetically less expensive than nitrate-derived N, the use of ammonium-based fertilizer is limited by the potential for toxicity symptoms. Nevertheless, previous studies have shown that exposure to elevated CO2 favors ammonium assimilation in plants. However, little is known about the impact of di...

Modern agriculture aims to reduce inputs without affecting yield and quality, moving towards organic and environmental friendly agricultural crop systems. One of the strategies to achieve this goal is the use of biostimulants, which are able to activate plant metabolism allowing an improvement in plant performance in a short time period and in a ch...

In higher plants ammonium (NH4⁺) assimilation occurs mainly through the glutamine synthetase/glutamate synthase (GS/GOGAT) pathway. Nevertheless, when plants are exposed to stress conditions, such as excess of ammonium, the contribution of alternative routes of ammonium assimilation such as glutamate dehydrogenase (GDH) and asparagine synthetase (A...

Pinus radiata is a highly valued conifer because of its timber production and its value as a reforestation plant. To increase production, nurseries currently use a nutritional method based on mineral fertilizers high in macronutrients. This produces individual trees which are unbalanced in size and more likely to suffer infections from phytopathoge...

Grasslands are subject to a wide range of land management practices that influence the exchange of the three main agricultural greenhouse gases (GHGs) that are related to agriculture: carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4). Improving nitrogen fertilization management practices through the use of nitrification inhibitors (NIs)...

Among strategies suggested to decrease agricultural soil N2O losses, the use of nitrifcation inhibitors such as DMPP (3,4-dimethylpyrazole phosphate) has been proposed. However, the efciency of DMPP might be afected by soil amendments, such as biochar, which has been shown to reduce N2O emissions. This study evaluated the synergic efect of a woody...

Nitrogen fertilization is a major force in global greenhouse gases emissions and causes environmental contamination through nitrate leaching. The use of nitrification inhibitors has been proven successful to mitigate these effects. However, there is an increasing concern about the undesired effects that their potential persistence in the soil or ac...

Balancing of leaf carbohydrates is a key process for maximising crop performance in elevated CO2 environments. With the aim of testing the role of the carbon sink-source relationship under different CO2 conditions, we performed two experiments with two barley genotypes (Harrington and RCSL-89) exposed to changing CO2. In Experiment 1, the genotypes...

El uso de inhibidores de la nitrificación como el 3,4-dimetilpirazol fosfato (DMPP) ha demostrado ser una estrategia eficaz para reducir las emisiones de N 2 O. Asimismo, la aplicación de biochar a suelos agrícolas se ha propuesto como herramienta efectiva para mitigar el cambio climático, ya que tiene potencial de secuestro de carbono recalcitrant...

In this work, we evaluate, in a winter wheat crop, the effect of two different land managements (CT and NT) and the use of the NI 3,4-dimethylpyrazolesuccinic acid (DMPSA) on N2O emissions. Under humid Mediterranean conditions, the addition of DMPSA to fertilizer allows to keep N2O emissions at the same level as in the unfertilized treatment in b...

Soil N 2 O emissions are mainly the result of the biological processes of nitrification and denitrification. Although both processes occur simultaneously under most soil conditions, nitrification is the preferential source of N 2 O under more aerated soils (water filled pore space WFPS < 60%) and denitrification is the dominant process in soils wit...

The increase of the global demand for dairy products is reflected in a rise of animal feed and forage productivity. In the coastal Atlantic climate conditions of northern Spain the maize-ryegrass rotation is a common management used to satisfy this forage demand. With the aim of mitigating greenhouse gases (GHG) emissions associated with fertilizat...

This work explores whether the natural abundance of N isotopes technique could be used to understand the movement of N within the plant during vegetative and grain filling phases in wheat crop (Triticum aestivum L.) under different fertilizer management strategies. We focus on the effect of splitting the same N dose through a third late amendment a...

Nitrification inhibitors are used to maintain ammonium available in the soil for longer periods while reducing nitrate leaching and N2O emission. In this work we evaluated the potential toxicity effects of 3,4-dimethylpyrazole phosphate (DMPP) and 2-(N-3,4-dimethyl-1H-pyrazol-1-yl) succinic acid isomeric mixture (DMPSA) nitrification inhibitors. In...

Nitrous oxide (N2O) emissions have been increasing as a result of intensive nitrogen (N) fertilisation. Soil nitrification and denitrification are the main sources of N2O, and the use of ammonium-based fertilisers combined with nitrification inhibitors (NIs) could be useful in mitigating N2O emissions from agricultural systems. In this work we look...

An adequate carbon supply is fundamental for plants to thrive under ammonium stress. In this work we studied the mechanisms involved in tomato (Solanum lycopersicum L.) response to ammonium toxicity when grown under ambient or elevated CO2 conditions (400 ppm or 800 ppm CO2). Tomato roots were observed to be the primary organ dealing with ammonium...

In the last decades, intensive agriculture management and the application of nitrogen fertilizer have led to high nitrogen losses to the environment. Among these losses is the soil emission of the potent greenhouse gas nitrous oxide (N2O) which is mainly produced by the soil microbial processes of nitrification and denitrification. The use of nitri...

Nitrous oxide (N2O) is the strongest greenhouse gas associated with agricultural soils. Current agricultural practices, based on the use of N fertilizers, can lead to environmental N losses, with some losses occurring as N2O emissions. Among the strategies suggested by the Intergovernmental Panel on Climate Change to decrease N losses through agric...

The use of nitrogen (N) fertilizers in crops increases their yield but can modify their quality and lead to environmental problems by the emission of greenhouse gases (GHG). One of the strategies for mitigating this emission is the use of nitrification inhibitors (NI) as 3,4-dimethylpyrazole phosphate (DMPP). Additionally, the increased persistence...

Nowadays agricultural practices are based in the use of N fertilizers which can lead to environmentalN losses. These losses can occur as nitrous oxide (N2O) emissions as result of the microbial processesof nitrification and denitrification. N2O together with carbon dioxide (CO2) and methane (CH4) are thestrongest greenhouse gases (GHG) associated w...

Accessing different nitrogen (N) sources involves a profound adaptation of plant metabolism. In this study, a quantitative proteomic approach was used to further understand how the model plant Arabidopsis thaliana adjusts to different N sources when grown exclusively under nitrate or ammonium nutrition. Proteome data evidenced that glucosinolate me...

Predicted reduced precipitation, enhanced evaporative demand and increasing CO2 in the atmosphere will strongly influence wheat production. The association of wheat with arbuscular mycorrhizal fungi (AMF) improves growth under stressful conditions. Our objective was to test the influence of mycorrhizal inoculation on yield, and accumulation of macr...

Ammonium nutrition often represents an important growth-limiting stress in plants. Some of the symptoms that plants present under ammonium nutrition have been associated with pH deregulation, in fact external medium pH control is known to improve plants ammonium tolerance. However, the way plant cell metabolism adjusts to these changes is not compl...

Root length of plants grown under different conditions of pH (5.7 or 6.7), N source (NO3- or NH4+), and concentration (2 or 10 mM). Statistical analysis was described in Figure 1. Columns represent mean ± se (n = 25–35).

Pearson correlations between GDH activity and tissue NH4+ content in roots and leaves of plants grown under nitrate or ammonium as nitrogen source. Correlation lines are presented only if p < 0.05.

Pearson correlations between ICDH activity and amino acid content in roots and leaves of plants grown under nitrate or ammonium as nitrogen source. Correlation lines are presented only if p < 0.05.

External medium pH monitoring during Arabidopsis plants growth under different conditions of pH (5.7 or 6.7), N source (NO3- or NH4+) and concentration (2 or 10 mM).

Zoom of gln1-4 and gn1-5 genes expression shown in Figure 4.

GDH enzyme activity measured on its deaminating sense from shoots (A) and roots (B) of plants grown under different conditions of pH (5.7 or 6.7), N source (NO3- or NH4+), and concentration (2 or 10 mM). Statistical analysis was described in Figure 1. Columns represent mean ± se (n = 3). Each sample is a pool of three plants.

Ammonium (NH4+) toxicity typically occurs in plants exposed to high environmental NH4+ concentration. NH4+ assimilating capacity may act as a biochemical mechanism avoiding its toxic accumulation but requires a fine tuning between nitrogen assimilating enzymes and carbon anaplerotic routes. In this work, we hypothesized that extra C supply, exposin...

Cell structure and alterations in tissue organization were analyzed for roots of Zea maysL. amylacea as a consequence of high salinity and boron (B) levels. Saline treatment concentrations were 100 mM NaCl (Low salinity, L) and 430 mM NaCl (High salinity, H). An excess of B was supplied as boric acid to obtain 20 (334 µM) and 40 (668 µM) mg B kg–1...

Nitrate (NO3(-)) and ammonium (NH4(+)) are the main forms of nitrogen available in the soil for plants. Excessive NH4(+) accumulation in tissues is toxic for plants and exclusive NH4(+)-based nutrition enhances this effect. Ammonium toxicity syndrome commonly includes growth impairment, ion imbalance and chlorosis among others. In this work, we obs...