Current overview of S-nitrosoglutathione (GSNO) in higher plants

S-nitrosoglutathione is a nitric oxide-derived molecule, generated by the interaction of nitric oxide (NO) with reduced glutathione (GSH) in a process called S-nitrosylation (Figure 1). The reaction appears to take place either through the formation of N2O3 or the addition of NO to a glutathionyl radical formed during this reaction (Broniowska et al., 2013). GSNO is regarded as an intracellular NO reservoir as well as a vehicle of NO throughout the cell, which enables NO biological activity to expand. GSNO is also considered to be the most abundant low-molecular-mass (LMM) S-nitrosothiol (SNO). This family includes other molecules such as S-nitrosocysteine (CySNO) and S-nitrosocysteinylglycine (GlyCySNO), which have been the subject of less study in the field of plant research. There is another group of SNOs called high-molecular mass (HMM) SNOs which are produced by NO binding to sulfhydryl (-SH) groups present in specific cysteine residues of proteins. Figure 1 shows a simple model of GSNO metabolism and its interactions with other molecules in cells where different reactions including S-nitrosylation, S-transnitrosation, and S-glutathionylation are involved (Hogg, 2002; Martínez-Ruiz and Lamas, 2007). In plants, research has focused on the importance of total SNOs in specific stress situations (Feechan et al., 2005; Chaki et al., 2011a) and on the identification of the potential protein targets of S-nitrosylation as this kind of post-translational modification can alter the function of the affected proteins (Astier et al., 2012). Initial studies in this area exogenously applied GSNO in order to identify the pool of potential protein candidates (Lindermayr et al., 2005). However, less attention has been paid to the abundance, distribution, and modulation of endogenous GSNO under natural and stress conditions. In this article, we will provide a current overview of GSNO in higher plants. [EN]Work in our laboratories is supported by ERDF-cofinanced grants from the Ministry of Science and Innovation (BIO2012-33904 and BFU2011-22779)Peer reviewe

Protein Tyrosine Nitration during Development and Abiotic Stress Response in Plants

In recent years, the study of nitric oxide (NO) in plant systems has attracted the attention of many researchers. A growing number of investigations have shown the significance of NO as a signal molecule or as a molecule involved in the response against (a)biotic processes. NO can be responsible of the post-translational modifications (NO-PTM) of target proteins by mechanisms such as the nitration of tyrosine residues. The study of protein tyrosine nitration during development and under biotic and adverse environmental conditions has increased in the last decade; nevertheless, there is also an endogenous nitration which seems to have regulatory functions. Moreover, the advance in proteome techniques has enabled the identification of new nitrated proteins, showing the high variability among plant organs, development stage and species. Finally, it may be important to discern between a widespread protein nitration because of greater RNS content, and the specific nitration of key targets which could affect cell-signaling processes. In view of the above point, we present a mini-review that offers an update about the endogenous protein tyrosine nitration, during plant development and under several abiotic stress conditions.This study was supported by an ERDF grant co-financed by the Ministry of Economy and Competitiveness (project BIO2015-66390-P) and Junta de Andalucía (groups BIO286 and BIO192). Research in FJC laboratory is supported by an ERDF grant co-financed by the Ministry of Economy and Competitiveness (AGL2015-65104-P).Peer reviewedPeer Reviewe

Short-Term Low Temperature Induces Nitro-Oxidative Stress that Deregulates the NADP-Malic Enzyme Function by Tyrosine Nitration in Arabidopsis thaliana

Low temperature (LT) negatively affects plant growth and development via the alteration of the metabolism of reactive oxygen and nitrogen species (ROS and RNS). Among RNS, tyrosine nitration, the addition of an NO2 group to a tyrosine residue, can modulate reduced nicotinamide-dinucleotide phosphate (NADPH)-generating systems and, therefore, can alter the levels of NADPH, a key cofactor in cellular redox homeostasis. NADPH also acts as an indispensable electron donor within a wide range of enzymatic reactions, biosynthetic pathways, and detoxification processes, which could affect plant viability. To extend our knowledge about the regulation of this key cofactor by this nitric oxide (NO)-related post-translational modification, we analyzed the effect of tyrosine nitration on another NADPH-generating enzyme, the NADP-malic enzyme (NADP-ME), under LT stress. In Arabidopsis thaliana seedlings exposed to short-term LT (4 °C for 48 h), a 50% growth reduction accompanied by an increase in the content of superoxide, nitric oxide, and peroxynitrite, in addition to diminished cytosolic NADP-ME activity, were found. In vitro assays confirmed that peroxynitrite inhibits cytosolic NADP-ME2 activity due to tyrosine nitration. The mass spectrometric analysis of nitrated NADP-ME2 enabled us to determine that Tyr-73 was exclusively nitrated to 3-nitrotyrosine by peroxynitrite. The in silico analysis of the Arabidopsis NADP-ME2 protein sequence suggests that Tyr73 nitration could disrupt the interactions between the specific amino acids responsible for protein structure stability. In conclusion, the present data show that short-term LT stress affects the metabolism of ROS and RNS, which appears to negatively modulate the activity of cytosolic NADP-ME through the tyrosine nitration processThis research was funded by ERDF grants co-financed by the Ministry of Economy and Competitiveness (project PGC2018-096405-B-I00) and the Junta de Andalucía (group BIO286) in Spain. Research in FJ-C lab is supported by an ERDF-co-financed grant from the Ministry of Economy and Competitiveness (AGL2015-65104-P) and Junta de Andalucía (group BIO-192), Spain. Postdoctoral researcher J.B.-M. was funded by the Ministry of Economy and Competitiveness (Spain) within Juan de la Cierva-Incorporación program (IJCI-2015-23438)

Diseño, aplicación y evaluación de animaciones Flash como material docente no presencial en prácticas de Bioquímica

El Área de Bioquímica y Biología Molecular ha desarrollado un conjunto de animaciones Flash interactivas específicamente diseñadas para reforzar la comprensión de conceptos, técnicas y aplicaciones instrumentales de las sesiones de prácticas de las asignaturas que imparte el Área. Las animaciones han sido incluidas en el servidor web de la Universidad de Jaén y los alumnos han dispuesto permanentemente de este material de apoyo a través de enlaces web desde la plataforma Docencia Virtual. Para valorar el grado de satisfacción, se han realizado encuestas de valoración de este material en alumnos de diferentes Grados de Ciencias durante el curso académico 2009/2010

Early and delayed long-term transcriptional changes and short-term transient responses during cold acclimation in olive leaves

Low temperature severely affects plant growth and development. To overcome this constraint, several plant species from regions having a cool season have evolved an adaptive response, called cold acclimation. We have studied this response in olive tree (Olea europaea L.) cv. Picual. Biochemical stress markers and cold-stress symptoms were detected after the first 24 h as sagging leaves. After 5 days, the plants were found to have completely recovered. Control and cold-stressed plants were sequenced by Illumina HiSeq 1000 paired-end technique. We also assembled a new olive transcriptome comprising 157,799 unigenes and found 6,309 unigenes differentially expressed in response to cold. Three types of response that led to cold acclimation were found: short-term transient response, early long-term response, and late long-term response. These subsets of unigenes were related to different biological processes. Early responses involved many cold-stress-responsive genes coding for, among many other things, C-repeat binding factor transcription factors, fatty acid desaturases, wax synthesis, and oligosaccharide metabolism. After long-term exposure to cold, a large proportion of gene down-regulation was found, including photosynthesis and plant growth genes. Up-regulated genes after long-term cold exposure were related to organelle fusion, nucleus organization, and DNA integration, including retrotransposons.This work was supported by grant AGR-5948 from Junta de Andalucía (Consejería de Economía, Innovación y Ciencia) and Ministerio de Ciencia e Innovación. Funding to pay the Open Access publication charges for this article was provided by the University of Jaén.Peer reviewe

Cold response in olive tree; A RNAseq study

Póster presentado en el COST TD801 StatSeq 5th Workshop, celebrado en Helsinki del 24 al 26 de abril de 2013.Low temperature severely affects plant growth and development. Several plant species have evolved an adaptive response, named cold acclimation. In order to study this response in olive tree (Olea europaea), we maintained twomonths- old vegetative propagated olive trees cv. Picual at low temperature (14h at 10ºC with light, 10h at 4ºC at the dark) for 15 days. Control plants were maintained in field growing conditions. Cold stress symptoms were observed after the first 24h as sagging leaf and biochemical stress markers. After 5 days the plants were observed completely recovered. We extracted RNA from leaves of three control plants and the same number from 24h and 10 days cold stressed plants. We pooled RNA and made two cDNA libraries for sequencing. We used Illumina HiSeq 1000 sequencer.Peer Reviewe

Gene Expression Pattern in Olive Tree Organs (Olea europaea L.)

peer-reviewedThe olive tree (Olea europaea L.) was one of the first plant species in history to be domesticated. Throughout olive domestication, gene expression has undergone drastic changes that may affect tissue/organ-specific genes. This is an RNA-seq study of the transcriptomic activity of different tissues/organs from adult olive tree cv. “Picual” under field conditions. This analysis unveiled 53,456 genes with expression in at least one tissue, 32,030 of which were expressed in all organs and 19,575 were found to be potential housekeeping genes. In addition, the specific expression pattern in each plant part was studied. The flower was clearly the organ with the most exclusively expressed genes, 3529, many of which were involved in reproduction. Many of these organ-specific genes are generally involved in regulatory activities and have a nuclear protein localization, except for leaves, where there are also many genes with a plastid localization. This was also observed in stems to a lesser extent. Moreover, pathogen defense and immunity pathways were highly represented in roots. These data show a complex pattern of gene expression in different organs, and provide relevant data about housekeeping and organ-specific genes in cultivated olive

Nitro-fatty acids in plant signaling: Nitro-linolenic acid induces the molecular chaperone network in Arabidopsis

Nitro-fatty acids (NO-FAs) are the product of the reaction between reactive nitrogen species derived of nitric oxide (NO) and unsaturated fatty acids. In animal systems, NO-FAs are considered novel signaling mediators of cell function based on a proven antiinflammatory response. Nevertheless, the interaction of NO with fatty acids in plant systems has scarcely been studied. Here, we examine the endogenous occurrence of nitro-linolenic acid (NO-Ln) in Arabidopsis and the modulation of NO-Ln levels throughout this plant’s development by mass spectrometry. The observed levels of this NO-FA at picomolar concentrations suggested its role as a signaling effector of cell function. In fact, a transcriptomic analysis by RNA-seq technology established a clear signaling role for this molecule, demonstrating that NO-Ln was involved in plant defense response against different abiotic-stress conditions, mainly by inducing heat shock proteins and supporting a conserved mechanism of action in both animal and plant defense processes. Bioinformatics analysis revealed that NO-Ln was also involved in the response to oxidative stress conditions, mainly depicted by HO, reactive oxygen species, and oxygen-containing compound responses, with a high induction of ascorbate peroxidase expression. Closely related to these results, NO-Ln levels significantly rose under several abiotic-stress conditions such as wounding or exposure to salinity, cadmium, and low temperature, thus validating the outcomes found by RNA-seq technology. Jointly, to our knowledge, these are the first results showing the endogenous presence of NO-Ln in Arabidopsis (Arabidopsis thaliana) and supporting the strong signaling role of these molecules in the defense mechanism against different abiotic-stress situations.C.M.-P. thanks the University of Jaén for funding the Ph.D. fellowship. LC-MS/MS analyses were carried out at the Technical Services Department of the University of Granada, Spain. ACSCs were kindly provided by Dr. Juan Bautista Arellano from the Institute of Natural Resources and Agrobiology (IRNASA-CSIC, Salamanca, Spain).Peer Reviewe

ABP: aplicación del "Aprendizaje Basado en Problemas" a la docencia de las asignaturas del Área de Bioquímica y Biología Molecular

Se ha aplicado el sistema de Aprendizaje basado en problemas (ABP) como una herramienta formativa más en la docencia de las asignaturas impartidas por nuestra Área de Conocimiento. El ABP obliga al alumno a diseñar una estrategia para afrontar un determinado problema, buscar información específica sobre el mismo y aplicarla de forma práctica en su resolución. Para poner en práctica este sistema se han ideado una serie de problemas adecuados a los contenidos y nivel de cada una de las asignaturas. El objetivo ha sido el de formar a los alumnos mediante situaciones similares a las que se encontrarán en el futuro ejercicio de su actividad profesional, estimulando así su implicación y participación en las asignaturas. Se ha desarrollado mediante exposiciones en clase y tutorías con grupos de trabajo. Se incluyen ejemplos de ABP de las distintas asignaturas. Para evaluar los resultados de este sistema se ha realizado una encuesta a los alumnos participantes cuyos resultados también se muestran

Elaboración y Desarrollo de un Programa de Autoevaluación con Refuerzo para las Asignaturas “Bioquímica” y “Técnicas Bioquímicas” de la Licenciatura en Biología

La enseñanza universitaria tradicionalmente se ha basado en la clase magistral con el apoyo principalmente de la pizarra y la fotocopiadora. Pero progresivamente y, sobre todo, en los últimos años, se han ido incorporando otros elementos de ayuda a la docencia, que incluyen tanto medios técnicos, Vg. proyectores, vídeos, como informáticos, Vg. programas para la docencia e Internet, no sólo como fuente de información, sino también como elemento deapoyo docente.El proceso de adaptación a las directrices de la Declaración de Bolonia con la creación de un Espacio Europeo de Enseñanza Superior, nos obliga a un profundo cambio pedagógico. La docencia está cambiando, y el estudiante pasa a ser el protagonista principal del proceso de aprendizaje El proceso de aprendizaje, a su vez, pasa a ser más activo y participativo, y los objetivos se basan tanto en la adquisición de conocimientos como en la capacidad para aplicarlos.La evaluación es uno de los objetivos principales del proceso docente. Con la evaluación se consigue información sobre los logros alcanzados por el alumno durante su aprendizaje, y sirve, además, para evidenciar los aspectos de la docencia que puedan ser susceptibles de mejora.Normalmente se considera la evaluación como una simple herramienta de calificación de los alumnos y no como una herramienta que permita al alumno realizar un seguimiento de su aprendizaje de forma autónoma, libre y continuada y, a su vez, le posibilite aprender de sus errores.Un sistema de evaluación adecuado mejorará la calidad de la docencia por su papel reforzador para el alumno. En consecuencia, debe usarse para enseñar al alumno