Increased temperatures caused by climate change constitute a significant threat to agriculture and food security. The selection of improved crop varieties with greater tolerance to heat stress is crucial for the future of agriculture. To overcome this challenge, four traditional tomato varieties from the Mediterranean basin and two commercial genotypes were selected to characterize their responses at high temperatures. The screening of phenotypes under heat shock conditions allowed to classify the tomato genotypes as: heat-sensitive: TH-30, ADX2; intermediate: ISR-10 and Ailsa Craig; heat-tolerant: MM and MO-10. These results reveal the intra-genetical variation of heat stress responses, which can be exploited as promising sources of tolerance to climate change conditions. Two different thermotolerance strategies were observed. The MO-10 plants tolerance was based on the control of the leaf cooling mechanism and the rapid RBOHB activation and ABA signaling pathways. The variety MM displayed a different strategy based on the activation of HSP70 and 90, as well as accumulation of phenolic compounds correlated with early induction of PAL expression. The importance of secondary metabolism in the recovery phase has been also revealed. Understanding the molecular events allowing plants to overcome heat stress constitutes a promising approach for selecting climate resilient tomato varieties.

Higher plants suffer from mild heat stress when temperatures increase by 5 °C above optimum growth temperatures. This produces changes at the cellular and metabolic levels, allowing plants to adapt to heat conditions. This study investigated an increase of 5 °C above the optimum growth temperature (26 °C) of tomato plants in the tomato—Pseudomonas syringae pv. tomato pathosystem. A temperature increase above 26 °C affects plant development, the defensive pathways activated against Pseudomonas syringae pv. tomato strain DC3000 (PstDC3000), and the bacterial growth and virulence machinery. The results demonstrated that tomato plants were able to acclimate to mild heat stress, showing no symptoms of damage. Moreover, plants subjected to a 5 °C increase (T31 °C plants) showed higher basal levels of metabolites such as proline and putrescine, which probably act as compatible osmolytes. This demonstrates their importance as key components of thermotolerance. When grown under mild heat stress, plants were less susceptible to PstDC3000 and showed increased accumulation of abscisic acid, jasmonic acid-isoleucine, and spermine. In addition, the temperature increase negatively affected the infectivity of PstDC3000. Inhibition of the genes responsible for quorum sensing establishment and synthesis of flagellin and coronatine was observed in bacteria extracted from T31 °C plants. Analysis of the genes involved in the synthesis of the type III secretion system indicates the important role of this system in bacterial growth under these conditions. As the known resistance mechanisms involved in the defense against PstDC3000 were not activated, the changes in its virulence mechanisms under high temperatures may explain the lower infection observed in the T31 °C plants.

Anaerobic treatment of industrial wastewater using upflow anaerobic reactors is an extended trend due to its high efficiency and biogas production potential, but its implementation in some sectors is limited due to the complexity and toxicity of the wastewaters. In this study, a two‐stage expanded granular sludge bed (EGSB) reactors system has been investigated at both bench and pilot scale for the treatment of complex and toxic real wastewater from a petrochemical industry. The effect of different operational parameters including organic loading rate (OLR), hydraulic retention time (HRT) and influent characteristics over COD removal and biogas production and composition have been studied. Additionally, biomass specific methanogenic activity (SMA) and wastewater toxicity have been evaluated after long‐term operation. Optimum total HRT of 24 h has been determined resulting in total COD and SO₄²⁻ removal of 56.30 ± 5.25% and 31.68 ± 14.71%, respectively, at pilot scale, and average biogas production of 93.47 ± 34.92 NL/day with 67.01 ± 10.23 %CH₄ content and 5210.11 ± 6802.27 ppmv of H₂S. SMA and toxicity tests have confirmed inhibitory and toxic effects of wastewater over anaerobic biomass with average maximum inhibition of 65.34% in the unacclimated anaerobic inoculum while chronic toxicity produced a decrease of an order of magnitude in SMA after 600 days of operation. This study demonstrates the feasibility of applying an anaerobic treatment to this wastewater using EGSB reactors between a 0.97–1.74 gCOD/L/day OLR range. Nonetheless, periodic reinoculation would be necessary for long‐term operation due to chronic toxicity of the wastewater exerted on the anaerobic biomass.Practitioner points: A two‐stage EGSB reactors system has been operated at bench and pilot scale to treat complex and toxic petrochemical wastewater. Optimal total HRT of 24 h resulted in average COD removal ranging from 40% to 60%. SMA and toxicity tests have been performed to study long‐term acclimation, detecting an activity depletion of an order of magnitude.

El grado de Ingeniería Agroalimentaria y del Medio Rural de la Universitat Jaume I de Castelló viene aplicando, en su segundo curso, un proyecto multidisciplinar utilizando el Aprendizaje Basado en Proyectos como recurso docente y pretende que los estudiantes adquieran competencias que les ayuden a enfrentarse a su futuro profesional. Este sistema de enseñanza-aprendizaje se ha llevado a cabo durante los tres cursos que está implantado el grado. Una vez asignado un tipo de explotación agrícola concreta y utilizando las herramientas del trabajo en equipo, los estudiantes deben ser capaces de desarrollar un proyecto sobre la explotación con propuestas de mejora que sean factibles y que abarquen aspectos relacionados con las diferentes disciplinas implicadas, aplicando los conocimientos adquiridos en éstas. El presente trabajo incluye los resultados obtenidos durante los tres años del proyecto desde dos puntos de vista importantes: la satisfacción del estudiante y los resultados de aprendizaje. Además se presentan las propuestas de mejora aplicadas en cada curso como respuesta a las debilidades detectadas durante el proceso. Los resultados demuestran que el método utilizado ha favorecido la adquisición de las competencias propuestas. Además el enfoque multidisciplinar ha propiciado mejores resultados que los alcanzados por los estudiantes que realizaron trabajos unidisciplinares. Por otro lado, aunque las acciones de mejora han permitido solventar algunos de los problemas detectados, siguen persistiendo carencias, sobre todo a nivel de trabajo en equipo y de tutorización, que se proponen como mejoras para el futuro.