Role of Jasmonic Acid Pathway in Tomato Plant-Pseudomonas syringae Interaction

The jasmonic acid pathway has been considered as the backbone of the response against necrotrophic pathogens. However, a hemi-biotrophic pathogen, such as Pseudomonas syringae, has taken advantage of the crosstalk between the different plant hormones in order to manipulate the responses for its own interest. Despite that, the way in which Pseudomonas syringae releases coronatine to activate jasmonic acid-derived responses and block the activation of salicylic acid-mediated responses is widely known. However, the implication of the jasmonic intermediates in the plant-Pseudomonas interaction is not studied yet. In this work, we analyzed the response of both, plant and bacteria using SiOPR3 tomato plants. Interestingly, SiOPR3 plants are more resistant to infection with Pseudomonas. The gene expression of bacteria showed that, in SiOPR3 plants, the activation of pathogenicity is repressed in comparison to wild type plants, suggesting that the jasmonic acid pathway might play a role in the pathogenicity of the bacteria. Moreover, treatments with JA restore the susceptibility as well as activate the expression of bacterial pathogenicity genes. The observed results suggest that a complete jasmonic acid pathway is necessary for the susceptibility of tomato plants to Pseudomonas syringae

Employability skills: a system of recognition at Universitat Jaume I

Proceedings 10th International Conference of Education, Research and Innovation (ICERI2017)Following CEDEFOP [1] the employability is “the combination of factors which enable individuals to progress towards or get into employment, to stay in employment and to progress during their career.” Also, theories of employability have become increasingly complex and multi-dimensional in the last decades. [2]. Employability depends on the knowledge, skills and attitudes, how the graduate use those assets, and how the graduates present them to employers. Moreover, there is an amount of work developed by Careers Services and faculties enhancing employabiity of our students through diferent initiatives and programmes (placements, workshops, career guidance, traning for job search, and so forth). Also University Jaume I has developed an educational model, in which their 10 principles we find “promotion of employability and the smart entrepreneurial spirit”. However, from the vicerectorate for Students, Employment and Educational Innovation we want to go a step forward to enhance employability of our graduates launching a formal document that will be an edge in their curriculum. The main aim of this system is to show a potential employer evidences of high impact employability soft and hard competences, achieved by graduates and undergraduates during their studies. This competences have been developed by the students through active participation in both extracurricular and curricular training, increasing of sensitivity and experience (skills acquired by practice) activities organised both by the University or other organisations, and recognised by an expert committee. The aim of this communication is to explain the features of the system: background, requeriments for each activity, administrative procedure, and results. Also we will comment on progress and future challenges of the system

Ammonium enhances resistance to salinity stress in citrus plants

In this work, we demonstrate that NH4+ nutrition in citrange Carrizo plants acts as an inducer of resistance against salinity conditions. We investigated its mode of action and provide evidence that NH4+ confers resistance by priming abscisic acid and polyamines, and enhances H2O2 and proline basal content. Moreover, we observed reduced Cl− uptake as well as enhanced PHGPx expression after salt stress. Control and N-NH4+ plants showed optimal growth. However, N-NH4+ plants displayed greater dry weight and total lateral roots than control plants, but these differences were not observed for primary root length. Our results revealed that N-NH4+ treatment induces a similar phenotypical response to the recent stress-induced morphogenetic response (SIMRs). The hypothesis is that N-NH4+ treatment triggers mild chronic stress in citrange Carrizo plants, which might explain the SIMR observed. Moreover, we observed modulators of stress signaling, such as H2O2 in N-NH4+ plants, which could acts as an intermediary between stress and the development of the SIMR phenotype. This observation suggests that NH4+ treatments induce a mild stress condition that primes the citrange Carrizo defense response by stress imprinting and confers protection against subsequent salt stress

Reciprocal regulation between AtNRT2.1 and AtAMT1.1 expression and the kinetics of NH4+ and NO3− influxes

Our results show that AtNRT2.1 expression has a positive effect on the NH4+ ion influx, mediated by the HATS, as also occurs with AtAMT1.1 expression on the NO3− ion influx. AtNRT2.1 expression plays a key role in the regulation of AtAMT1.1 expression and in the NH4+ ion influx, differentiating the nitrogen source, and particularly, the lack of it. Nitrogen starvation produces a compensatory effect by AtAMT1.1 when there is an absence of the AtNRT2.1 gene. Our results also show that, in the atnrt2 mutant lacking both AtNRT2.1 and AtNRT2.2, gene functions present different kinetic parameters on the NH4+ ion influx mediated by the HATS, according to the source and availability of nitrogen. Finally, the absence of AMT1.1 also produces changes in the kinetic parameters of the NO3− influx, showing different Vmax values depending on the source of nitrogen available

Priming by Hexanoic Acid Induce Activation of Mevalonic and Linolenic Pathways and Promotes the Emission of Plant Volatiles

Hexanoic acid (Hx) is a short natural monocarboxylic acid present in some fruits and plants. Previous studies reported that soil drench application of this acid induces effective resistance in tomato plants against Botrytis cinerea and Pseudomonas syringae and in citrus against Alternaria alternata and Xanthomonas citri. In this work, we performed an in deep study of the metabolic changes produced in citrus by the application of Hx in response to the challenge pathogen A. alternata, focusing on the response of the plant. Moreover, we used 13C labeled hexanoic to analyze its behavior inside the plants. Finally, we studied the volatile emission of the treated plants after the challenge inoculation. Drench application of 13C labeled hexanoic demonstrated that this molecule stays in the roots and is not mobilized to the leaves, suggesting long distance induction of resistance. Moreover, the study of the metabolic profile showed an alteration of more than 200 molecules differentially induced by the application of the compound and the inoculation with the fungus. Bioinformatics analysis of data showed that most of these altered molecules could be related with the mevalonic and linolenic pathways suggesting the implication of these pathways in the induced resistance mediated by Hx. Finally, the application of this compound showed an enhancement of the emission of 17 volatile metabolites. Taken together, this study indicates that after the application of Hx this compound remains in the roots, provoking molecular changes that may trigger the defensive response in the rest of the plant mediated by changes in the mevalonic and linolenic pathways and enhancing the emission of volatile compounds, suggesting for the first time the implication of mevalonic pathway in response to hexanoic application.This work was supported by grants from “Programa de formació del personal investigador” of the Universitat Jaume I (PREDOC/2009/24), the Spanish Ministry of Science and Innovation AGL2010-22300-C03-01-02 and AGL2013-49023-C03-01-02-R co-funded by the European Regional Development Fund (ERDF)

Advances in endophytic fungi research: a data analysis of 25 years of achievements and challenges

Research on fungal endophytes has demonstrated the ability to improve crop performance and protect host plants against diverse biotic and abiotic stresses. Yet, despite the exponential growth of this topic, a whole outline to reflect the relevance and extent of each study type is missing. Hence, we performed an analysis of all available literature to expose the characteristics and limitations of this research field. Our results suggested that, overall, there is still a tendency to study the most known models in plant-fungal-stress combinations (ascomycetous fungi, grasses, abiotic stress). Fungal endophytes in dicot plants or against biotic stress, though promising, are still quite unexplored. All these data could lead future studies to assess less considered study factors that might help discern the beneficial effects of fungal endophytes with more extent and accuracy

Putrescine biosynthetic pathways modulate root growth differently in tomato seedlings grown under different N sources

The biosynthesis of putrescine is mainly driven by arginine decarboxylase (ADC) and ornithine decarboxylase (ODC). Hence, in this study, we generated independent ADC and ODC transgenic silenced tomato lines (SilADC and SilODC, respectively) to test the effect of defective ADC and ODC gene expression on root development under nitrate (NN) or ammonium (NA) conditions. The results showed that SilODC seedlings displayed an increase in ADC expression that led to polyamine accumulation, suggesting a compensatory effect of ADC. However, this effect was not observed in SilADC seedlings. These pathways are involved in different growth processes. The SilADC seedlings showed an increase in fresh weight, shoot length, lateral root number and shoot:root ratio under the NN source and an enhancement in fresh weight, and shoot and root length under NA conditions. However, SilODC seedlings displayed greater weight and shoot length under the NN source, whereas a decrease in lateral root density was found under NA conditions. Moreover, two overexpressed ODC lines were generated to check the relevance of the compensatory effect of the ADC pathway when ODC was silenced. These overexpressed lines showed not only an enhancement of almost all the studied growth parameters under both N sources but also an amelioration of ammonium syndrome under NA conditions. Together, these results reflect the importance of both pathways in plant growth, particularly ODC silencing, which requires compensation by ADC induction.Funding for open access charge: CRUE-Universitat Jaume

Ammonium transport and CitAMT1 expression are regulated by N in Citrus plants

Citrus seedlings (Citrus sinensis L. Osbeck × Poncirus trifoliata Blanco) were used to describe the effects of different N treatments on the NH4 + influx mediated by high- and low-affinity transport systems (HATS and LATS, respectively) and CitAMT1 gene expression. Results show that Citrus plants favor NH4 + over NO3 − influx mediated by HATS and LATS when both N sources are present in the nutrient solution and Citrus plants display a much higher capacity to take up NH4 + than NO3 −. Furthermore, NH4 + exerts a regulatory effect on NH4 + HATS activity and CitAMT1 expression, both are down-regulated by high N status of the plant, but specifically stimulated by NH4 + and the balance between these two opposite effects depends on the prior nutrition regime of the plant. On the other hand, supply of NO3 − inhibitsCitAMT1 expression but doesn’t affect NH4 + HATS activity on the roots. To explain this discrepancy, it is possible that other CitAMT1 transporters, up-regulated by N limitation, but not repressed by NO3 − could be involved in the stimulation of NH4 + HATS activity under pure NO3 − nutrition or CitAMT1 transporter could be regulated at the post-transcriptional leve

Investigación sobre estrategias de aprendizaje para alumnos de inglés de nivel A2 en educación secundaria

En este artículo se presentan los resultados de un trabajo de investigación acerca de cómo progresa un grupo de inglés de un colegio de educación secundaria, al ser instruido de manera consciente en el uso de estrategias de aprendizaje de lenguas. Se trata de un estudio cuasiexperimental, comparativo entre dos cursos compuestos por alumnos adolescentes de segundo año, nivel A2 (según el Marco Europeo de Referencia para las Lenguas, 2002), de un colegio de nivel secundario. Se estableció como objetivo general analizar la efectividad de instruir de distintas maneras a los estudiantes de educación secundaria de nivel A2 en el uso de estrategias de aprendizaje de lenguas extranjeras. El trabajo se realizó bajo el paradigma de investigación acción ya que interesaba comprender las acciones que posibilitan la mejora de los aprendizajes de estos alumnos mediante una aproximación exploratoria y con el objetivo de analizar lo que sucede en el aula en relación a la enseñanza específica interpretando hechos que tienen lugar desde el punto de vista de los participantes en el proceso educativo. Los resultados permitieron concluir que existe una relación directa entre la instrucción en el uso de estrategias de aprendizaje y un mejor rendimiento de los estudiantes

Exogenous Carbon Compounds Modulate Tomato Root Development

NO3 − is not only a nutrient, but also a signaling compound that plays an important role in several plant processes, like root development. The present study aimed to investigate the effect of three different exogenous C compounds (sucrose, glucose, 2-oxoglutarate) added to NO3 − nutrition on C/N, auxin and antioxidant metabolisms in 10-day-old tomato seedlings. Sucrose and glucose supplementation enhanced primary root (PR) length, lateral root number and root density, while 2-oxoglutarate negatively affected them. This phenomenon was accompanied by a slight increase in NRT2.1 and GS1 gene expression, together with an increase in LAX2 and LAX3 and a decrease in LAX4 in the roots growing under sucrose and glucose sources. The addition of 2-oxoglutarate enhanced the expression of NiR, GDH, PEPC1, LAX1, LAX3 and the antioxidant gene SOD Cl. Taken together, these findings contribute to a better understanding of how these C sources can modulate N uptake and C/N, auxin and antioxidant gene expression, which could be useful for improving nitrogen use efficienc