Search

In this research study, we evaluated the effect of mild water deficit on the physiological response of the flag leaf at the milky grain development stage and the final grain yield and mineral content at maturity of bread wheat (Tritticum aestivum cv Gazul). Three plants were grown in 5-L pots containing a mixture of perlite and vermiculite in a volumetric ratio of 3 to 1 as the soilless substrate and under greenhouse conditions from February 2023 to July 2023. After seed sowing, the potted plants were fertigated at full-holding capacity (100% FC) three days per week. After the unfolding of the fourth leaf, pots were divided into two blocks: one half of the pots followed the same fertigation pattern at 100% FC while fertigation was reduced to 65% FC in the other half until plant maturity and senescence. At the milky grain development stage, when plants water demand was highest, we assessed leaf morphological traits, photosynthesis related traits, content of proline, free amino acids, ascorbic acid, glutathione and nitrate at two consecutive days. At maturity, plants were harvested to determine final biomass, water use efficiency, grain yield, and mineral content of the flag leaves and the grains.

Singlet oxygen is a reactive oxygen species that causes oxidative damage to plant cells, but intriguingly it can also act as a signalling molecule to reprogram gene expression required to induce plant physiological/cellular responses. Singlet oxygen photosensitization in plants mainly occurs in chloroplasts after the molecular collision of ground-state molecular oxygen with triplet-excited-state chlorophyll. Singlet oxygen direct detection through phosphorescence emission in chloroplasts is a herculean task due to its extremely low luminescence quantum yield. Because of this, indirect alternative methods have been developed for its detection in biological systems, for example, by measuring the changes in the EPR signal or fluorescence intensity of singlet oxygen reaction-based probes. The singlet oxygen chemiluminescence (SOCL) is a chemiluminescence probe with high sensitivity and selectivity towards singlet oxygen and promising use to detect it in living cells without the inconvenience of low stability of the EPR signal of spin probes in the presence of redox compounds, spurious light scattering coming from the light source required for the excitation of fluorescence probes or the light emission of endogenous fluorescent molecules like chlorophyll in chloroplasts. The protocol presented in this chapter describes the first steps to characterizing singlet oxygen production within the biological system under study; this is accomplished through monitoring molecular oxygen consumption by SOCL using a Clark-type oxygen electrode and measuring the chemiluminescence generated by SOCL 1,2-dioxetane using a spectrofluorometer. For singlet oxygen detection within living cells, a version of SOCL with increased membrane permeability (SOCL-CPP) is described.

Reactive oxygen species (ROS) are produced by energy transfer and electron transport in plant chloroplast thylakoids at non-toxic levels under normal growth conditions, but at threatening levels under adverse or fluctuating environmental conditions. Among chloroplast ROS, singlet oxygen and superoxide anion radical, respectively, produced by photosystem II (PSII) and PSI, are known to be the major ROS under several stress conditions. Both are very unlikely to diffuse out of chloroplasts, but they are instead capable of triggering ROS-mediated chloroplast operational retrograde signalling to activate defence gene expression in concert with hormones and other molecular compounds. Therefore, their detection, identification and localization in vivo or in biological preparations is a priority for a deeper understanding of their role in (concurrent) regulation of plant growth and defence responses. Here, we present two EPR spin traps, abbreviated as TEMPD-HCl and DEPMPO, to detect and identify ROS in complex systems, such as isolated thylakoids, together with some hints and cautions to perform reliable spin trapping experiments.

Plants function in symbiosis with numerous microorganisms, which might contribute to their adaptation and performance. In this study, we tested whether fungal strains in symbiotic interaction with roots of Celtica gigantea, a wild grass adapted to nutrient-poor soils in semiarid habitats, could improve the field performance of the agricultural cereal tritordeum (Triticum durum × Hordeum chilense). Seedlings of tritordeum were inoculated with 12 different fungal strains isolated from roots of Celtica gigantea that were first proved to promote the growth of tritordeum plants under greenhouse conditions. The inoculated seedlings were transplanted to field plots at two locations belonging to different climatic zones in terms of mean temperatures and precipitation in the Iberian Peninsula. Only one strain, Diaporthe iberica T6, had a significant effect on plant height, number of tillers and grain yield in one location. This result showed a substantial divergence between the results of greenhouse and field tests. In terms of grain nutritional quality, several parameters were differentially affected at both locations: Diaporthe T6, Pleosporales T7, Zygomycota T29 and Zygomycota T80 increased the content of total carotenoids, mainly lutein, in the colder location; whereas gluten proteins increased with several treatments in the warmer location. In conclusion, early inoculation of tritordeum plants with fungal symbionts had substantial beneficial effects on subsequent plant growth and development in the field. Regarding grain nutritional quality, the effect of inoculation was affected by the agroclimatic differences between both field locations.

In this study, we tested whether fungal strains in symbiotic interaction with roots of Celtica gigantea, a wild grass adapted to nutrient-poor soils in semiarid habitats, could improve the field performance of the agricultural cereal tritordeum (Triticum durum x Hordeum chilense). Seedlings of tritordeum were inoculated with 12 different fungal strains isolated from roots of Celtica gigantea. The inoculated seedlings were transplanted to field plots at two locations belonging to different climatic zones in terms of mean temperatures and precipitation in the Iberian Peninsula (Salamanca and Córdoba). Both experiments were conducted under rainfed conditions. Plant height, measured as the length from the base of the stem to the tip of the top leaf, and tiller number were recorded when plants were at a growth stage equivalent to stage 5 on the Feekes scale for wheat. When plants had five leaves fully expanded, a sample was collected for nutrient analysis. Plants were harvested at maturity and the number of heads per plant, grain weight, and 1000 grain weight were determined. Several grain quality parameters were analyzed

This article comments on: Sapeta H, Yokono M, Takabayashi A, Ueno Y, Cordeiro AM, Hara T, Tanaka A, Akimoto S, Oliveira MM, Tanaka R. 2023. Reversible down-regulation of photosystems I and II leads to fast photosynthesis recovery after long-term drought in Jatropha curcas. Journal of Experimental Botany 74, 336–351.

Functional symbiosis with fungal endophytes can help plants adapt to environmental stress. Diaporthe atlantica is one of the most abundant fungal taxa associated with roots of Festuca rubra subsp. pruinosa, a grass growing in sea cliffs. This study aimed to investigate the ability of a strain of this fungus to ameliorate the impact of drought stress on tomato plants. In a greenhouse experiment, tomato plants were inoculated with Diaporthe atlantica strain EB4 and exposed to two alternative water regimes: well-watered and drought stress. Several physiological and biochemical plant parameters were evaluated. Inoculation with Diaporthe promoted plant growth in both water treatments. A significant interactive effect of Diaporthe-inoculation and water-regime showed that symbiotic plants had higher photosynthetic capacity, water-use efficiency, nutrient uptake (N, P, K, Fe and Zn), and proline content under drought stress, but not under well-watered conditions. In addition, Diaporthe improved the enzymatic antioxidant response of plants under drought, through an induced mechanism, in which catalase activity was modulated and conferred protection against reactive oxygen species generation during stress. The results support that Diaporthe atlantica plays a positive role in the modulation of tomato plant responses to drought stress by combining various processes such as improving photosynthetic capacity, nutrient uptake, enzymatic antioxidant response and osmo-protectant accumulation. Thus, drought stress in tomato can be enhanced with symbiotic fungi

The continous rise in the atmospheric CO2 concentration and temperature of the Earth's surface threatens the nutritional value of agricultural edibles. Used as a major staple food, wheat grain provides a large proportion of proteins, minerals and vitamins for human nutrition. This study uncovers potential biomarkers for the improvement of nutritional quality at different N availabilites.

El trigo harinero es uno de los alimentos básicos para millones de personas en todo el mundo. Las predicciones de cambio climático reflejan aumentos en la concentración atmosférica de CO2 y la temperatura media de la superficie terrestre, junto con periodos de sequía más frecuentes e intensos que pueden afectar al rendimiento del trigo. En este contexto, se estudió el impacto del déficit hídrico moderado en la biomasa y el metabolismo primario del C N de la hoja bandera y la espiga de plantas de trigo crecidas en condiciones de CO2 y temperatura elevados. Las plantas se cultivaron en cámaras de crecimiento de ambiente controlado bajo dos regímenes hídricos: déficit hídrico moderado (65% capacidad de campo aplicado desde la fase vegetativa) y control hídrico (100% capacidad de campo). La biomasa, el área verde y el contenido de carbohidratos, nitrato, aminoácidos y proteínas solubles se determinó en la hoja bandera y espiga en la fase de emergencia de la espiga del trigo. El déficit hídrico redujo el peso seco en la hoja y el porcentaje de humedad y el área verde en ambos órganos, siendo el efecto más acusado en la hoja que en la espiga, mientras que aumentó significativamente el contenido de glucosa y fructosa en la hoja bandera pero no en la espiga. La sequía indujo un aumento del contenido de nitrato a nivel foliar y un descenso de almidón y nitrato en la espiga. En ambos órganos, el déficit hídrico condujo a un incremento de la masa por área y del contenido de fructanos y aminoácidos, y no tuvo efecto en el contenido de sacarosa y proteínas. Estos datos muestran evidencias de que la acumulación de compuestos osmóticamente activos en respuesta al déficit hídrico fue mayor a nivel foliar que en la espiga, resaltando la importancia de la evaluación de los distintos órganos de las plantas de trigo en la adaptación al cambio climático

Wheat is an essential cereal in human nutrition. It provides 20% of the calories in daily intake and is an important source of proteins, carbhydrates, minerals, vitamins, and phytochemicales. In the coming decades, the globla demand for wheat will increase with the growing population worldwide, whereas its procutivity may decrease due to climate change.

Wheat is one of the main staple foods worldwide due to its nutritional value and high consumption by human population. However, its production is expected to decline because of the effect of global climate change. Together with the increase in atmospheric (CO2) and Earth's average surface temperature, there will be stronger and more frequent episodes of drought threating wheat productivity, especially in the Mediterranean zone. In this study, we aim to investigate the effect of water deficit on the physiological and photosynthetic response of the flag leaf of three different genoytypes of two wheat species (Triticum aestivum L. cv Gazul and CIMMYT-HTWSN 41 and Triticum durum L. cv. Regallo) grown under a controlled environment, in which CO2 was kept at 900 ppm and the daily and sesaonal temperature was 4ºC above the current average of Salamanca region

This study provides new evidences on the imbalance between grain yield and nutritional quality of wheat under elevated CO₂ and high temperature conditions. Our results give valuable insights into the physiological and biochemical pathways underlying the trade‐off between grain yield and quality in wheat genotypes

Among abiotic stresses, drought is the main cause of crop yield loss. Studies on water deficit effects are commonly carried out using pots inside greenhouses or controlled-environment chambers, whiche allow more stable conditions. However, comparisons of main results from different laboratories point to different approaches defining and maintaining water conditions as the main cause of low experimental reproductibility

La sequía es uno de los estreses abióticos que más reduce el crecimiento y la productividad de los cultivos. El uso de macetas para estudiar el efecto del déficit hídrico en plantas permite diseñar ensayos en invernaderos o cámaras de crecimiento bajo condiciones controladas. Sin embargo, la variabilidad en el diseño experimental para definir y mantener las condiciones de déficit hídrico suele ser el principal motivo por el cual se observa una baja reproducibilidad entre experimentos de diferentes laboratorios. El potencial hídrico del suelo (XX), definido como la energía potencial del agua retenida en el suelo por unidad de volumen con respecto al agua pura como referencia, es un parámetro físicoquímico útil para establecer el nivel de sequía con independencia del sustrato utilizado; aunque el uso de sensores para medir XX conlleva ciertas consideraciones, en particular aquellas relacionadas con el rango de sensibilidad, la posición y orientación en la maceta, así como el tamaño de estas. El presente estudio preliminar tuvo dos objetivos: primero, relacionar XX con una capacidad de campo (CC) establecida y, segundo, monitorizar cambios en XX del sustrato durante el desarrollo de plantas de trigo (Triticum aestivum L. cv Gazul) bajo condiciones de estrés hídrico moderado. Se utilizó como sustrato una mezcla de perlita: vermiculita (3:1, v/v). En el desarrollo vegetativo, se indujo un déficit hídrico del 65% de CC, mientras que las plantas de control hídrico se mantuvieron al 100% de CC. El seguimiento de la pérdida de agua por evapotranspiración se realizó por métodos gravimétricos, reponiendo la cantidad de agua necesaria para mantener el sustrato al nivel hídrico establecido. Los datos registrados del XXX muestran un patrón oscilante, que aumentó notablemente en fases avanzadas del desarrollo de la planta, particularmente desde el estado de bota. En la madurez, las plantas cultivadas en condiciones de estrés hídrico tuvieron una biomasa y un rendimiento de grano m

El trigo es un cereal esencial en la alimentación humana ya que proporciona el 20% de las calorías de la dieta y es una fuente importante de proteínas, carbohidratos, minerales, vitaminas y fitoquímicos. En las próximas décadas, el aumento de CO2 y temperatura de la atmósfera irá acompañado de periodos de sequía más frecuentes, intensos y duraderos que podrán afectar a la productividad y calidad de los cultivos agroalimentarios, incluido el trigo, y comprometer la seguridad alimentaria. Por ello, el objetivo de este trabajo fue estudiar el efecto del déficit hídrico moderado y terminal en el rendimiento y calidad del grano de plantas de trigo crecidas en condiciones de CO2 y temperatura elevada. Con esta finalidad, se cultivaron plantas de trigo en cámaras de crecimiento de ambiente controlado bajo un déficit hídrico moderado de larga duración (65% capacidad de campo aplicado en fase vegetativa), déficit hídrico terminal (50% capacidad de campo inducido en la emergencia de la espiga) y control hídrico (100% capacidad de campo). En la madurez del cultivo, se determinó la biomasa, los componentes del rendimiento y parámetros de calidad del grano (minerales, carbohidratos, proteínas, compuestos fenólicos y capacidad antioxidante total). Ambos déficits hídricos redujeron la biomasa y el rendimiento, el número de espigas y granos, la relación C/N y el contenido de Ca, Mn y Zn, mientras que aumentaron el número de tallos no productivos y el contenido de proteínas y K en el grano. El déficit hídrico terminal disminuyó, en comparación con las plantas de control hídrico, el índice de cosecha y el contenido de fructosa, y aumentó la capacidad antioxidante total y el contenido de compuestos fenólicos y S en el grano. El déficit hídrico moderado aumentó la relación raíz/parte aérea de las plantas de trigo y el contenido de Na con respecto al control hídrico. Entre ambos déficits hídricos hubo diferencias en la biomasa del tallo, la relación C/N, capacidad antioxidante y el cont

Se espera que el aumento de la concentración de CO2 atmosférico y la concomitante subida de la temperatura media global provoquen periodos de sequía más frecuentes e intensos, particularmente en zonas mediterráneas. Este cambio climático limitará el crecimiento y productividad del trigo, uno de los cereales más cultivados en el mundo. Por ello, el objetivo del estudio fue investigar los efectos de distintos regímenes hídricos en la hoja bandera y la espiga del trigo Triticum aestivum L. cv Gazul en un ambiente previsto para finales de siglo. Las plantas se cultivaron dentro de una cámara de crecimiento de ambiente controlado, donde la concentración de CO2 se incrementó hasta alcanzar 900 ppm y la temperatura se fijó en 26ºC/16º C día/noche, 4º C por encima de los valores medios actuales de la temperatura día/noche en Salamanca. Se regó con dos regímenes hídricos diferentes: un déficit hídrico de larga duración (LWD), comenzando en la fase de crecimiento vegetativo, y un déficit hídrico terminal (TWD) a partir de la fase de la emergencia de la espiga. En ambos órganos se analizaron los cambios en biomasa, morfología, contenido de prolina (Pro), ascorbato (AsA) y glutatión (GSH), y varias actividades enzimáticas antioxidantes. Los resultados mostraron un comportamiento distinto de los órganos en respuesta a los dos déficits hídricos. LWD en la hoja bandera redujo significativamente la biomasa, el área, el porcentaje del contenido de humedad (MC%) y el contenido de AsA, mientras que aumentó el peso seco por área (DMA), el contenido de Pro y las actividades catalasa y glutatión reductasa. TWD no produjo cambios significativos en hoja con respecto al tratamiento control. Por el contrario, ambos déficits hídricos afectaron de manera similar a las espigas, disminuyendo la biomasa, el DMA y el contenido de GSH y aumentando el MC%. TWD causó además un incremento en el contenido de Pro y la actividad superóxido dismutasa en espiga. Asimismo, los datos indicaron que el elevado

The projected continuous rise in atmospheric CO2 accompanied by an increase in global mean temperatures will bring together more frequent and severe drought episodes, particularly in Mediterranean regions. Wheat is one of the most cultivated cereals in the world, and these future climate changes will negatively affect its growth and productivity, especially during the reproductive stage. In the present study, we aim to investigate the effect of different water regimes on flag leaves and ears of a bread wheat genotype Gazul. Potted wheat plants were grown in an environmentcontrolled chamber in which CO2 above the current average temperatures typically experienced in the province of Salamanca (Spain) and was maintained at 26 ºC/16 ºC day/night. The plants were subjected to two different water deficits: a long water deficit (LWD) applied at the vegetative growth stage, and a terminal water deficit (TWD) applied at the ear emergence stage. Both organs were analysed for changes in biomass and morphology, the content of proline (Pro), ascorbate (AsA) and glutathione (GSH) as well as enzymatic antioxidant activities. The statistical analysis was performed using the R software. The obtained results showed a different behaviour of the organs toward the water deficit regimes. LWD significantly reduced the biomass, area, moisture content percentage (MC%) and AsA content but caused an increase in dry matter per area (DMA), Pro content, catalase and glutathione reductase activities of the flag leaf. However, TWD treatment produced no significant changes for this organ compared to control. In contrast, both treatments similarly affected the ears by reducing the biomass, DMA and GSH content, and enhancing MC%. Additionally, TWD caused an increase in Pro content and superoxide dismutase activity. In conclusion, the results showed that elevated CO2 might mitigate the severity of both water deficits and thereby reduce ROS production in both organs. Furthermore, the multifactorial ana

Wheat is an essential cereal in human nutrition. It provides 20% of the calories in daily intake and is an important source of proteins, carbohydrates, minerals, vitamins, and phytochemicals. In the coming decades, the global demand for wheat will increase with the growing population worldwide, whereas its productivity may decrease due to climate change. In this context, the increase in the concentration of CO2 and temperature of the atmosphere will be accompanied by more frequent, intense and long-lasting periods of drought, which, in turn, could jeopardize food security. The objective of this study was to investigate the effect of drought stress on grain yield and quality of wheat grown under combined elevated CO2 and high temperature. To achieve this goal, wheat plants were grown in controlled environment growth chambers under long-term moderate water deficit applied from the vegetative developmental stage (65% field capacity), terminal water deficit (50% field capacity) applied from the ear emergence, and well-watered conditions (100% field capacity). At crop maturity, the plant biomass and the grain yield and quality were assessed. Both water deficits decreased plant biomass, grain yield, ear and grain number, C/N ratio and Ca, Mn and Zn contents but increased the content of proteins and K in the grain. Long-term moderate water deficit increased the root/shoot ratio and the Na content compared to well-watered conditions. Terminal water deficit reduced the harvest index and fructose content but increased the total antioxidant capacity and the content of polyphenols and S in the grain. Between water deficits, there were differences in the stem biomass, C/N ratio, total antioxidant capacity and the content of proteins, polyphenols, Na and S. This study reflects the negative impact of complex environmental conditions associated with climate change on the wheat grain yield and quality

Understanding the kinetic mechanism of enzyme inactivation by suicide substrate is of relevance for the optimal design of new drugs with pharmacological and therapeutic applications. Suicide substrate inactivation usually occurs via a two-step mechanism, although there are enzymes such as peroxidase and catalase in which the suicide inactivation by H2O2 happens in a single step. The approximate solution of the ordinary differential equation (ODE) system of the one step suicide substrate inactivation kinetics for a uni–uni reaction following the irreversible Michaelis–Menten model was previously analytically solved when accumulation of the substrate–enzyme complex was negligible, however not for more complex models, such as a ping-pong reaction, in which the enzyme is present in two active states during the catalytic turnover. To solve this issue, a theoretical approach was followed, in which the standard quasi-steady state and reactant stationary approximations were invoked. These approximations allowed for solving the ODE system of a ping-pong reaction with one substrate undergoing disproportionation when suicide inactivation was also present. Although the approximate analytical solutions were rather unwieldy, they were still valuable in qualitative analyses to explore the time course of the reaction products and identify the enzyme active state that irreversibly reacted with the suicide substrate during the reaction.

Predicted increases in the atmospheric CO2 concentration and the earth’s mean surface temperature will be accompanied by a higher incidence of drought events. These environmental changes are likely to adversely affect crop productivity and quality, including wheat, an essential food in the human diet. We investigated the primary C-N metabolism response to drought stress at the whole-plant level and its dependence on plant development in bread wheat grown under combined elevated CO2 and temperature. With this aim, the content of carbohydrates, nitrate, proteins and amino acids, together with the biomass were assessed in flag leaves and roots of wheat grown in controlled environment chambers at both ear emergence and anthesis stages. Multifactorial analysis revealed that the organ was the main factor explaining data variation. The physiological and biochemical traits in the flag leaves were more affected by drought than growth stage, leading to an accumulation of soluble carbohydrates, nitrate and amino acids. By contrast, roots were affected by the developmental stages but not by the treatment. The root content of fructose, glucose, starch and amino acids was higher at ear emergence than anthesis, whereas the accumulation of sucrose, fructans, proteins and nitrate increased at the latest growth stage. This study provides new insights into the reprograming of primary metabolism at whole plant level throughout the development in response to the future climate scenario, which could help to select traits ensuring sustainable food production systems that strengthen capacity for adaptation to climate change following the Sustainable Development Goals of 2030 Agenda

Triticum aestivum L. cv. Gazul is a spring wheat widely cultivated in Castilla y León (Spain). Potted plants were grown in a scenario emulating the climate change environmental conditions expected by the end of this century, i.e., with elevated CO2 and high temperature under two water deficit regimes: long (LWD) and terminal (TWD). Changes in biomass and morphology, the content of proline (Pro), ascorbate (AsA) and glutathione (GSH), and enzymatic antioxidant activities were analyzed in flag leaves and ears. Additionally, leaf gas exchange was measured. LWD caused a decrease in biomass and AsA content but an increase in Pro content and catalase and GSH reductase activities in flag leaves, whereas TWD produced no significant changes. Photosynthesis was enhanced under both water deficit regimes. Increase in superoxide dismutase activity and Pro content was only observed in ears under TWD. The lack of a more acute effect of LWD and TWD on both organs was attributed to the ROS relieving effect of elevated CO2. Gazul acted as a drought tolerant variety with anisohydric behavior. A multifactorial analysis showed better adaptation of ears to water deficit than flag leaves, underlining the importance of this finding for breeding programs to improve grain yield under future climate change.

A rapid and high throughput protocol to measure the catalase activity in vitro has been designed. Catalase is an enzyme with unusual kinetic properties because it does not follow the standard Michaelis–Menten model and is inactivated by H2O2. This makes the analysis of the two rate equations of the second‐ordered reactions of the kinetic model rather complex. A two‐degree polynomial fitting of the experimental data is proposed after transforming the exponential form of the integrated rate equation of the [H2O2] into a polynomial using the Taylor series. The fitting is validated by establishing an experimental linear relationship between the initial rate of the H2O2 decomposition and the protein concentration, regardless of the suicide inactivation that catalase might undergo beyond t > 0. In addition, experimental considerations are taken into account to avoid statistical bias in the analysis of the catalase activity. ANOVA analyses show that the proposed protocol can be utilized to measure the initial rate of the H2O2 decomposition by catalase in 32 samples in triplicates if kept below 8 mM min−1 in the microplate wells. These kinetic and statistical analyses can pave the way for other antioxidant enzyme activity assays in microplate readers at small scale and low cost.

Festuca rubra subsp. pruinosa is a perennial grass that inhabits sea cliffs, a habitat where salinity and low nutrient availability occur. These plants have a rich fungal microbiome, and particularly common are their associations with Epichloë festucae in aboveground tissues and with Fusarium oxysporum and Periconia macrospinosa in roots. In this study, we hypothesized that these fungi could affect the performance of F. rubra plants under salinity, being important complements for plant habitat adaptation. Two lines of F. rubra, each one consisting of Epichloë-infected and Epichloë-free clones, were inoculated with the root endophytes (F. oxysporum and P. macrospinosa) and subjected to a salinity treatment. Under salinity, plants symbiotic with Epichloë had lower Na+ content than non-symbiotic plants, but this effect was not translated into plant growth. P. macrospinosa promoted leaf and root growth in the presence and absence of salinity, and F. oxysporum promoted leaf and root growth in the presence and absence of salinity, plus a decrease in leaf Na+ content under salinity. The growth responses could be due to functions related to improved nutrient acquisition, while the reduction of Na+ content might be associated with salinity tolerance and plant survival in the long term. Each of these three components of the F. rubra core mycobiome contributed with different functions, which are beneficial and complementary for plant adaptation to its habitat in sea cliffs. Although our results do not support an obvious role of Epichloë itself in FRP salt tolerance, there is evidence that Epichloë can interact with root endophytes, affecting host plant performance

The progressive rise in atmospheric CO2 concentrations and temperature associated with climate change is predicted to have a major impact on the productivity and quality of food crops. Therefore, food security is highly dependent on climate change. Following a survey with 60 bread wheat genotypes, here we investigated the genetic variation in grain yield and nutritional quality among 10 of these genotypes grown under elevated CO2 and temperature. With this purpose, the biomass production, grain yield-related traits, the grain concentration of starch, total protein, phenolic compounds, and mineral nutrients, together with the total antioxidant capacity, were determined. Variation among genotypes was found for almost all the studied traits. Higher grain and ear numbers were associated with increased grain yield but decreased grain total protein concentration and minerals such as Cu, Fe, Mg, Na, P, and Zn. Mineral nutrients were mainly associated with wheat biomass, whereas protein concentration was affected by plant biomass and yield-related traits. Associations among different nutrients and promising nutrient concentrations in some wheat genotypes were also found. This study demonstrates that the exploration of genetic diversity is a powerful approach, not only for selecting genotypes with improved quality, but also for dissecting the effect of the environment on grain yield and nutritional composition

Celtica gigantea (=Stipa gigantea) is a large perennial grass which grows in nutrient-poor sandy soils in semiarid zones of the western Iberian Peninsula. The purpose of this work was to find out if culturable fungal symbionts isolated from roots of this wild grass could have growth promoting activity in tritordeum, a hybrid cereal for human consumption. A survey of fungi from the root endosphere of C. gigantea produced an isolate collection consisting of 60 different taxa, mostly ascomycetes. Fungal strains were inoculated into tritordeum plants in order to evaluate their effect in leaf and root biomass, nutrient content, and total antioxidant capacity. Two consecutive screening processes were made to test endophyte effects in plants. In the first screening, 66 strains were inoculated into seedlings by dipping roots in a liquid suspension of inoculum. In the second screening, 13 strains selected from the first screening were inoculated by sowing seeds in a substrate containing inoculum. The inoculation method used in the second screening involved less labor and plant manipulation and improved the quantity and quality of the inoculum, making it more appropriate for big scale experimental inoculation pro-cedures. Several fungal strains promoted leaf or root growth. In particular, a strain belonging to the genus Diaporthe caused an increase in leaf and root biomass in both screening processes, suggesting that this endophyte might have a good potential for field application in tritordeum.

Global warming will inevitably affect crop development and productivity, increasing uncertainty regarding food production. The exploitation of genotypic variability can be a promising approach for selecting improved crop varieties that can counteract the adverse effects of future climate change. We investigated the natural variation in yield performance under combined elevated CO2 and high-temperature conditions in a set of 60 bread wheat genotypes (59 of the 8TH HTWSN CIMMYT collection and Gazul). Plant height, biomass production, yield components and phenological traits were assessed. Large variations in the selected traits were observed across genotypes. The CIMMYT genotypes showed higher biomass and grain yield when compared to Gazul, indicating that the former performed better than the latter under the studied environmental conditions. Principal component and hierarchical clustering analyses revealed that the 60 wheat genotypes employed different strategies to achieve final grain yield, highlighting that the genotypes that can preferentially increase grain and ear numbers per plant will display better yield responses under combined elevated levels of CO2 and temperature. This study demonstrates the success of the breeding programs under warmer temperatures and the plants’ capacity to respond to the concurrence of certain environmental factors, opening new opportunities for the selection of widely adapted climate-resilient wheat genotypes.

The asymptotes and transition points of the net CO2 assimilation (A/Ci) rate curves of the steady-state Farquhar–von Caemmerer–Berry (FvCB) model for leaf photosynthesis of C3 plants are examined in a theoretical study, which begins from the exploration of the standard equations of hyperbolae after rotating the coordinate system. The analysis of the A/Ci quadratic equations of the three limitation states of the FvCB model—abbreviated as Ac, Aj and Ap—allows us to conclude that their oblique asymptotes have a common slope that depends only on the mesophyll conductance to CO2 diffusion (gm). The limiting values for the transition points between any two states of the three limitation states c, j and p do not depend on gm, and the results are therefore valid for rectangular and non-rectangular hyperbola equations of the FvCB model. The analysis of the variation of the slopes of the asymptotes with gm casts doubts about the fulfilment of the steady-state conditions, particularly, when the net CO2 assimilation rate is inhibited at high CO2 concentrations. The application of the theoretical analysis to extended steady-state FvCB models, where the hyperbola equations of Ac, Aj and Ap are modified to accommodate nitrogen assimilation and amino acids export via the photorespiratory pathway, is also discussed

Triticum aestivum L. cv. Gazul is a spring wheat widely cultivated in Castilla y León (Spain). Potted plants were grown in a scenario emulating the climate change environmental conditions expected by the end of this century, i.e., with elevated CO2 and high temperature under two water deficit regimes: long (LWD) and terminal (TWD). Changes in biomass and morphology, the content of proline (Pro), ascorbate (AsA) and glutathione (GSH), and enzymatic antioxidant activities were analyzed in flag leaves and ears. Additionally, leaf gas exchange was measured. LWD caused a decrease in biomass and AsA content but an increase in Pro content and catalase and GSH reductase activities in flag leaves, whereas TWD produced no significant changes. Photosynthesis was enhanced under both water deficit regimes. Increase in superoxide dismutase activity and Pro content was only observed in ears under TWD. The lack of a more acute effect of LWD and TWD on both organs was attributed to the ROS relieving effect of elevated CO2. Gazul acted as a drought tolerant variety with anisohydric behavior. A multifactorial analysis showed better adaptation of ears to water deficit than flag leaves, underlining the importance of this finding for breeding programs to improve grain yield under future climate change.

A chemiluminescence probe for singlet oxygen 1O2 (SOCL) was investigated in phosphate buffer saline (PBS), either in the absence of proteins or containing bovine serum albumin (BSA). In the protein-free PBS, the reactivity of SOCL for methylene blue (MB)-photosensitized 1O2 was found to be moderate or low. The reaction yield increased with temperature and/or concentration of dissolved molecular oxygen. Unexpectedly, the presence of BSA boosted both the emissive nature and the thermal stability of the phenoxy-dioxetane intermediate formed in the chemiexcitation pathway. Isothermal titration calorimetry showed that SOCL has a moderate binding affinity for BSA and that entropy forces drive the formation of the SOCL-BSA complex. A model with two identical and independent binding sites was used to fit the binding isotherm data. Co-operative binding was observed when MB was present. Local viscosity factors and/or conformational restrictions of the BSA-bound SOCL phenoxy-dioxetane were proposed to contribute to the formation of the highly emissive benzoate ester during the chemically initiated electron exchange luminescence (CIEEL) process. These results led us to conclude that hydrophobic interactions of the SOCL with proteins can modify the emissive nature of its phenoxy-dioxetane, which should be taken into account when using SOCL or its cell-penetrating peptide derivative in living cells.