nuevos desafíos en espectroscopia vibracional

El principal objetivo de la Química Analítica Verde es la sustitución de metodologías contaminantes por otras más limpias, mediante: La reducción de reactivos y disolventes empleados en el pre-tratamiento y análisis de las muestras. Minimizar las cantidades y de la toxicidad de los compuestos empleados en las etapas de preparación y medida, especialmente mediante automatización y miniaturización. El desarrollo de metodologías directas de análisis sin uso de reactivos o disolventes y que, por tanto, no generen desechos tóxicos ni peligrosos. Las técnicas espectroscópicas junto con el uso de la quimiometría pueden ser una buena alternativa a los métodos tradicionales, ya que se pueden realizar medidas directas de las muestras sin el uso de reactivos ni disolventes. Por ello, mediante el uso de espectroscopia de infrarrojo cercano (NIR), medio (MIR) y Raman y, con la ayuda de herramientas quimiométricas, se han desarrollado metodologías que cumplen con los objetivos de la Química Analítica Verde. En aquellos casos en los que es necesaria una extracción de los analitos para su posterior determinación, se persiguió: Asegurar la alta calidad extracto/producto. El diseño de procesos de extracción reduciendo el consumo de energía. Uso de disolventes alternativos y productos renovables naturales, siendo los agro-solventes y bio-solventes los favoritos para reemplazar disolventes derivados del petróleo. Esta Tesis Doctoral se ha estructurado en 3 apartados. El primer apartado corresponde a los Objetivos, siendo el principal objetivo del proyecto, el desarrollo de una Química Analítica Verde a través de la simplificación de las formas de preparación de muestras y el empleo de metodologías directas mediante el uso de técnicas espectroscópicas en el análisis de muestras de diferente tipo. El segundo apartado corresponde a la Introducción, considerando: Química Analitica Verde. Se describen los conceptos fundamentales a partir de los 12 Principios de la Química Analítica Verde, así como la evaluación de los métodos analíticos. Espectroscopia vibracional. Se resumen los fundamentos de la espectroscopia vibracional en el infrarrojo medio, cercano y Raman. Quimiometría. Incluye las técnicas multivariantes utilizadas en esta Tesis Doctoral, ya sean supervisadas o no supervisadas, junto con la construcción, validación y evaluación de los modelos quimiométricos y descripción de los parámetros y pre-procesamientos más importantes. En el tercer apartado se recogen los Resultados Experimentales y Ámbito de aplicación de esta Tesis Doctoral, estructurados en 3 Partes y subdivididos en 9 capítulos, constituidos por 12 trabajos; 6 de los cuales se han publicado y los 6 restantes se han enviado a revistas científicas para ser publicados. Al final de cada capítulo se exponen las conclusiones más relevantes obtenidas en cada uno de los estudios realizados. Parte 1. Muestras de Alimentos En el Capítulo 1 se desarrolla un método rápido para la determinación de grasas, proteínas, hidratos de carbono y valor energético de tarritos de bebé, comida rápida para niños y menús de comedores universitarios, mediante el uso de medidas NI) y MIR utilizando métodos de calibración multivariante. (M.M Cascant, S. Garrigues, M. de la Guardia, Direct determination of major components in human diets and baby foods, Ana.l Bioanal. Chem., 407(2015) 1961:1972) En el Capítulo 2 se describe la determinación de los compuestos polares en aceite de fritura a través de 2 trabajos: 2.A. Comparación de la espectroscopia FT-NIR y FT-MIR en asociación con la calibración de mínimos cuadrados parciales (PLS) como herramienta verde para la determinación directa de compuestos polares en aceites de fritura. 2.B. Estudios previos para el desarrollo de un instrumento de bajo coste para la evaluación de la calidad del aceite de fritura. En el Capítulo 3, se estudia la determinación del contenido de los lípidos en aceite de salmón, mediante 2 trabajos: 3.A. Estudio de la extracción de los lípidos del salmón mediante disolventes alternativos al hexano con la ayuda de dos métodos computacionales como son; el Hansen Solubility Parameter (HSP) y Conductor-like Screening Model for Real Solvent (COSMO-RS) y mediante el uso de estudios experimentales para comparar los disolventes alternativos empleados con el hexano. Cabe mencionar que este trabajo fue realizado en una estancia predoctoral de tres meses en el Groupe de Recherche en Eco-Extraction de produits Naturels (GREEN) de la Universidad de Avignon (Francia) bajo la supervisión del Prof. Farid Chemat. (M.M. Cascant, C. Breil, S. Garrigues, M. de la Guardia, A.S. Fabiano-Tixier, F. Chemat, A green analytical chemistry approach for lipid extraction: computation methods in the selection of green solvents as alternative to hexane, Anal. Bioanal. Chem., 409(2017) 3527:3539) 3.B. Evaluación de la espectroscopia del infrarrojo cercano en combinación con los modelos PLS para la determinación simultánea de i) ácidos grasos como ácido oleico, ácido palmítico, ácido linolénico, ácido linoleico, ii) familias de ácidos grasos como omega-3, omega-6, ácidos grasos poliinsaturados, ácidos grasos monoinsaturados y ácidos grasos saturados, y iii) clases de lípidos como triacilglicéridos, diacilglicéridos, ácidos grasos libres y ergosterol en aceite de salmón Parte de este trabajo, relativo a la obtención de los resultados de referencia, se realizó durante la estancia predoctoral antes mencionada en el grupo GREEN de la Universidad de Avignon (Francia). El Capítulo 4 se basa en el Control de calidad de aditivos alimentarios mediante el uso de espectroscopia Raman e infrarrojo cercano (NIR) Parte 2. Muestras ambientales y de interés agrícola El Capítulo 5, basado en la evaluación de composts para su posterior uso en la agricultura mediante espectroscopia NIR y MIR, se encuentra compuesto por 2 trabajos: 5.A. Determinación de compuestos fenólicos totales (M.M. Cascant, M. Sisouane, S. Tahiri, M. El Krati, M.L. Cervera, S. Garrigues, M. de la Guardia, Determination of total phenolic compounds in compost by infrared spectroscopy, Talanta, 153(2016) 360:365) 5.B. Predicción del contenido de carbono orgánico y de nitrógeno total (M. Sisouane, M.M. Cascant, S. Tahiri, S. Garrigues, M. El Krati, G.E. Boutchich, M.L. Cervera, M. de la Guardia, Prediction of organic carbon and total nitrogen contents in organic wastes and their composts by Infrared spectroscopy and partial least square regression, Talanta, 167(2017) 352:358) En ambos casos las estrategias desarrolladas se basan en las medidas directas de las muestras sin tratamiento previo y sin el uso de reactivos ni disolventes. Los resultados obtenidos proporcionaron una capacidad predictiva aceptable para la determinación de compuestos fenólicos totales, mientras que para el caso del contenido de carbono orgánico y nitrógeno total los resultados obtenidos fueron aceptables para fines de cribado. El Capítulo 6 se refiere al desarrollo de una metodología para la determinación rápida y directa de analitos volátiles en suelos, combinando el espacio de cabeza (HS) con la espectroscopia infrarroja (FTIR). El Capítulo 7 se basa en la evaluación de un método flexible y automatizado para evitar las interferencias espectrales de vapores orgánicos en espectros FTIR medidos en fase de vapor, teniendo como compuesto diana la acetona, utilizando una metodología que combina el uso de espacio de cabeza con espectroscopia infrarroja para muestras de BTEX y EtOH. Parte 3. Muestras arqueológicas El Capítulo 8 describe un método analítico para la predicción de elementos alcalinotérreos y detección de procesos diagenéticos en muestras de huesos enterrados mediante espectroscopia de infrarrojo cercano. (M.M. Cascant, S. Rubio, G. Gallello, A. Pastor, S. Garrigues, M. de la Guardia, Prediction of alkaline earth elements in bone remains by near infrared spectroscopy, Talanta, 162(2017) 428:434) En el Capítulo 9 se hace referencia al uso del infrarrojo cercano para el estudio y clasificación de huesos quemados. El Análisis de Componentes Principales y la clasificación de conglomerados se utilizaron como técnicas exploratorias, a partir de los espectros de los huesos y de los sedimentos, para la selección de muestras de hueso quemado menos afectadas por procesos ambientales, para realizar adecuadamente estudios forenses. El Análisis Discriminante por Mínimos Cuadrados Parciales se utilizó para clasificar las muestras óseas según sus condiciones de combustión, y además, se construyeron modelos de regresión por mínimos cuadrados parciales para predecir la concentración de calcio, magnesio y estroncio de las muestras óseas. (M.M. Cascant, S. Rubio, G. Gallello, A. Pastor, S. Garrigues, M. de la Guardia, Burned bones forensic investigations employing near infrared spectroscopy, Vibrational Spectroscopy, 90 (2017) 21:30) Para finalizar, se presentan las Conclusiones generales de esta Tesis Doctoral; indicando que la espectroscopia vibracional combinada con el uso de herramientas quimiométricas ofrece una buena alternativa a los métodos tradicionales, siguiendo los principales objetivos de la Química Analítica Verde.The main objective of Green Analytical Chemistry is to replace polluting methodologies with cleaner ones by: Reducing reagents and solvents used in the pre-treatment and analysis of the samples. Minimizing the amounts and toxicity of the compounds used in the preparation and measurement steps, especially through automation and miniaturization. Developing direct analysis methodologies without the use of reagents or solvents which, therefore, do not generate toxic or hazardous waste. Spectroscopic techniques together with the use of chemometrics can be a good alternative to traditional methods, since direct measurements of the samples can be made without the use of reagents or solvents. Therefore, through the use of near infrared (NIR), middle (MIR) and Raman spectroscopy combined with chemometric tools, methodologies have been developed in order to meet the objectives of Green Analytical Chemistry. In those cases in which an extraction of the analytes is necessary for their subsequent determination, it was pursued to: Ensure high quality extract / product. Design extraction processes reducing energy consumption. Use alternative solvents and natural renewable products, being agro-solvents and bio-solvents the favorite to replace solvents derived from petroleum. This Doctoral Thesis has been structured in 3 sections. The first section corresponds to the Objectives, being the main objective of the project, the development of a Green Analytical Chemistry through the simplification of the sample preparation and the use of direct measurement methodologies by using spectroscopic techniques in the analysis of different kind of samples. Second section corresponds to the Introduction, considering: Green Analytical Chemistry. Fundamental concepts starting from the 12 Principles of Green Analytical Chemistry are described, as well as the greenness evaluation of analytical methods. Vibrational spectroscopy. Vibrational spectroscopy fundamentals in the middle, near infrared and Raman are summarized. Chemometrics. The multivariate techniques used in this Doctoral Thesis are comprehended here, whether supervised or unsupervised, together with the construction, validation and evaluation of the chemometric models and the description of the most important parameters and data pre-processing methods applied. In the third section, the Experimental Results and Scope of this Doctoral Thesis are presented and discussed. This section is structured in 3 parts and subdivided into 9 chapters, consisting of 12 works; 6 of which have been already published and the remaining 6 have been sent to scientific journals to be published. At the end of each chapter the most relevant conclusions obtained in each of the studies are presented. Part 1. Food Samples Chapter 1 corresponds to the development of a fast method for the determination of fats, proteins, carbohydrates and energetic values for baby jars, children´s fast food, and university canteens menus, by using NIR and MIR spectroscopy, and using multivariate calibration methods. (M.M Cascant, S. Garrigues, M. de la Guardia, Direct determination of major components in human diets and baby foods, Anal. Bioanal. Chem., 407(2015) 1961:1972) Chapter 2 describes the polar compounds determination in frying oil through 2 works: 2.A. Comparison of FT-NIR and FT-MIR spectroscopy in association with partial least squares (PLS) calibration models as a green tool for the direct determination of polar compounds in frying oils. 2.B. Previous studies for low cost instrument development for frying oil quality evaluation. In Chapter 3, the determination of the lipid content in salmon oil is studied by means of 2 works: 3.A. Study of lipid extraction from salmon using alternative solvents to hexane by using two computational methods such as; Hansen Solubility Parameter (HSP) and Conductor-like Screening Model for Real Solvent (COSMO-RS) and by using experimental studies to compare the alternative solvents used with hexane as a reference. It should be mentioned that this work was carried out in a three-month predoctoral stay at the Groupe de Recherche en Eco-Extraction of produits Naturels (GREEN) of the University of Avignon (France) under the supervision of Prof. Farid Chemat. (M.M. Cascant, C. Breil, S. Garrigues, M. de la Guardia, A.S. Fabiano-Tixier, F. Chemat, A green analytical chemistry approach for lipid extraction: computation methods in the selection of green solvents as alternative to hexane, Anal. Bioanal. Chem. 409(2017) 3527:3539). 3.B. Evaluation of the near infrared spectroscopy in combination of PLS models for the simultaneous determination of: i) fatty acids as oleic acid, palmitica acid, linolenic acid, linoleic acid, ii) fatty acid families as omega-3, omega-6, poliunsturated fatty acids, monounsaturated fatty acids and saturated fatty acids, and iii) lipid class as triacylglycerides, diacylglycerides, free fatty acids and ergosterol in salmon oil. Part of this work, related to obtaining the reference results, was performed during the abovementioned predoctoral stay in the group GREEN of the University of Avignon (France). Chapter 4 is based on the Quality Control of Food Additives through the use of Raman and NIR for direct measurement of samples contained into glass vials. Part 2. Environmental and agricultural interest samples Chapter 5, is devoted to the evaluation of composts for later use in agriculture using NIR and MIR spectroscopy, and consists of 2 works: 5.A. Determination of total phenolic compounds (M.M. Cascant, M. Sisouane, S. Tahiri, M. El Krati, M.L. Cervera, S. Garrigues, M. de la Guardia, Determination of total phenolic compounds in compost by infrared spectroscopy, Talanta, 153(2016) 360:365). 5.B. Prediction of organic carbon and total nitrogen content (M. Sisouane, M.M. Cascant, S. Tahiri, S. Garrigues, M. El Krati, G.E. Boutchich, M.L. Cervera, M. de la Guardia, Prediction of organic carbon and total nitrogen contents in organic wastes and their composts by Infrared spectroscopy and partial least square regression, Talanta, 167(2017) 352:358). In both cases developed strategies are based on the direct measurement of samples without previous pretreatment or the use of neither reagents nor solvents. Results obtained provided an acceptable predictive capability for determination of total phenolic compounds instead the poor capability for organic carbon and nitrogen content that is acceptable for screening purposes. Chapter 6 deals with the development of a methodology for the rapid and direct determination of volatile analytes in soils, combining headspace (HS) with infrared spectroscopy (FTIR). Chapter 7 is based on the evaluation of a flexible and automated method to avoid the spectral interferences of organic vapors in FTIR spectra measured in vapor phase, having acetone as a target compound, using a methodology that combines the headspace use with infrared spectroscopy for BTEX and EtOH samples. Part 3. Archaeological samples Chapter 8 describes an analytical method for the prediction of alkaline earth elements and detection of diagenetic processes in buried bones samples by near-infrared spectroscopy. (M.M. Cascant, S. Rubio, G. Gallello, A. Pastor, S. Garrigues, M. de la Guardia, Prediction of alkaline earth elements in bone remains by near infrared spectroscopy, Talanta, 162(2017) 428:434) Chapter 9 refers to the use of the near infrared for the study and classification of burned bones. Bone and sediment spectra were treated by Principal Component Analysis and cluster classification as exploratory techniques to select burned bone samples, less affected by environmental processes, to properly carry out forensic studies. Partial Least Square Discriminant Analysis was used to classify bone samples based on their burning conditions, and Partial Least Square regression models were built to predict calcium, magnesium and strontium concentration of bone samples. (M.M. Cascant, S. Rubio, G. Gallello, A. Pastor, S. Garrigues, M. de la Guardia, Burned bones forensic investigations employing near infrared spectroscopy, Vibrational Spectroscopy, 90 (2017) 21:30) Finally, the Final Conclusions of this Doctoral Thesis are presented; indicating that vibrational spectroscopy with the use of chemometrics tools offers a good alternative to traditional methods, keeping the objectives of Green Analytical Chemistry

Metabolomic Diversity of Human Milk Cells over the Course of Lactation - A Preliminary Study

Human milk (HM) is a complex biofluid containing a wide cell variety including epithelial cells and leukocytes. However, the cellular compositions and their phenotypic properties over the course of lactation are poorly understood. The aim of this preliminary study was to characterize the cellular metabolome of HM over the course of lactation. Cells were isolated via centrifugation and the cellular fraction was characterized via cytomorphology and immunocytochemical staining. Cell metabolites were extracted and analyzed using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-QqTOF-MS) in the positive and negative electrospray ionization modes. Immunocytochemical analysis revealed a high variability of the number of detected cells with relative median abundances of 98% of glandular epithelial cells, 1% of leukocytes, and 1% of keratinocytes. Significant correlations between the milk postnatal age with percentage of epithelial cells and leukocytes, and with total cell count were observed. Results from the Hierarchical Cluster Analysis of immunocytochemical profiles were very similar to those observed in the analysis of the metabolomic profiles. In addition, metabolic pathway analysis showed alterations in seven metabolic pathways correlating with postnatal age. This work paves the way for future investigations on changes in the metabolomic fraction of the cellular compartment of HM

Wheat Oxylipins in Response to Aphids, CO2 and Nitrogen Regimes

Wheat is critical for food security, and is challenged by biotic stresses, chiefly aphids and the viruses they transmit. The objective of this study was to determine whether aphids feeding on wheat could trigger a defensive plant reaction to oxidative stress that involved plant oxylipins. Plants were grown in chambers with a factorial combination of two nitrogen rates (100% N vs. 20% N in Hoagland solution), and two concentrations of CO2 (400 vs. 700 ppm). The seedlings were challenged with Rhopalosiphum padi or Sitobion avenae for 8 h. Wheat leaves produced phytoprostanes (PhytoPs) of the F1 series, and three types of phytofurans (PhytoFs): ent-16(RS)-13-epi-ST-Δ14-9-PhytoF, ent-16(RS)-9-epi-ST-Δ14-10-PhytoF and ent-9(RS)-12-epi-ST-Δ10-13-PhytoF. The oxylipin levels varied with aphids, but not with other experimental sources of variation. Both Rhopalosiphum padi and Sitobion avenae reduced the concentrations of ent-16(RS)-13-epi-ST-Δ14-9-PhytoF and ent-16(RS)-9-epi-ST-Δ14-10-PhytoF in relation to controls, but had little or no effect on PhytoPs. Our results are consistent with aphids affecting the levels of PUFAs (oxylipin precursors), which decreased the levels of PhytoFs in wheat leaves. Therefore, PhytoFs could be postulated as an early indicator of aphid hosting for this plant species. This is the first report on the quantification of non-enzymatic PhytoFs and PhytoPs in wheat leaves in response to aphids

Brain Oxygen Perfusion and Oxidative Stress Biomarkers in Fetuses with Congenital Heart Disease-A Retrospective, Case-Control Pilot Study.

Fetuses with congenital heart disease (CHD) have circulatory changes that may lead to predictable blood flow disturbances that may affect normal brain development. Hypoxemia and hypoperfusion may alter the redox balance leading to oxidative stress (OS), that can be assessed measuring stable end-products. OS biomarkers (OSB) were measured in amniotic fluid in fetuses with (n = 41) and without CHD (n = 44) and analyzed according to aortic flow, expected cyanosis after birth, and a CHD classification derived from this. Birth head circumference (HC) was used as a neurodevelopment biomarker. CHD fetuses had higher levels of ortho-Tyrosine (o-Tyr) than controls (p = 0.0003). There were no differences in o-Tyr levels considering aortic flow obstruction (p = 0.617). Fetuses with expected extreme cyanosis presented the highest levels of o-Tyr (p = 0.003). Among groups of CHD, fetuses without aortic obstruction and extreme cyanosis had the highest levels of o-Tyr (p = 0.005). CHD patients had lower HC than controls (p = 0.023), without correlation with OSB. Patients with HC < 10th percentile, presented high levels of o-Tyr (p = 0.024). Fetuses with CHD showed increased OSB and lower HC when compared to controls, especially those with expected extreme cyanosis. Our results suggest that increased levels of OSB are more influenced by the effect of low oxygenation than by aortic flow obstruction. Future studies with larger sample size are needed to further investigate the role of OSB as an early predictor of neurodevelopmental problems in CHD survivors

Wheat Oxylipins in Response to Aphids, CO2 and Nitrogen Regimes

Wheat is critical for food security, and is challenged by biotic stresses, chiefly aphids and the viruses they transmit. The objective of this study was to determine whether aphids feeding on wheat could trigger a defensive plant reaction to oxidative stress that involved plant oxylipins. Plants were grown in chambers with a factorial combination of two nitrogen rates (100% N vs. 20% N in Hoagland solution), and two concentrations of CO2 (400 vs. 700 ppm). The seedlings were challenged with Rhopalosiphum padi or Sitobion avenae for 8 h. Wheat leaves produced phytoprostanes (PhytoPs) of the F1 series, and three types of phytofurans (PhytoFs): ent-16(RS)-13-epi-ST-Δ14-9-PhytoF, ent-16(RS)-9-epi-ST-Δ14-10-PhytoF and ent-9(RS)-12-epi-ST-Δ10-13-PhytoF. The oxylipin levels varied with aphids, but not with other experimental sources of variation. Both Rhopalosiphum padi and Sitobion avenae reduced the concentrations of ent-16(RS)-13-epi-ST-Δ14-9-PhytoF and ent-16(RS)-9-epi-ST-Δ14-10-PhytoF in relation to controls, but had little or no effect on PhytoPs. Our results are consistent with aphids affecting the levels of PUFAs (oxylipin precursors), which decreased the levels of PhytoFs in wheat leaves. Therefore, PhytoFs could be postulated as an early indicator of aphid hosting for this plant species. This is the first report on the quantification of non-enzymatic PhytoFs and PhytoPs in wheat leaves in response to aphids.Agricultura y Veterinari

Searching molecular biomarkers correlating with BSID-III at 24 months in infants with neonatal hypoxic-ischemic encephalopathy

An early prediction of outcomes of neonatal hypoxic-ischemic encephalopathy (NE) is of key importance in reducing neonatal mortality and morbidity. The objectives were (i) to analyze the characteristics of miRNA expression and metabolic patterns of neonates with NE and (ii) to assess their predictive performance for neurodevelopmental outcomes. Plasma samples from moderate/severe NE patients (N = 92) of the HYPOTOP study were collected before, during, and after therapeutic hypothermia (TH) and compared to a control group (healthy term infants). The expression of miRNAs and concentrations of metabolites (hypoxia-related and energy, steroid, and tryptophan metabolisms) were analyzed. Neurodevelopmental outcomes were evaluated at 24 months postnatal age using Bayley Scales of Infant Development, ed. III, BSID-III. Differences in miRNA and metabolic profiles were found between NE vs. control infants, abnormal (i.e., mildly and moderately abnormal and severe) vs. normal, and severe vs. non-severe (i.e., normal and mildly and moderately abnormal) BSID-III. 4-Androstene-3,17-dione, testosterone, betaine, xanthine, and lactate were suitable for BSID-III outcome prediction (receiver operating characteristic areas under the curve (AUCs) ≥ 0.6), as well as 68 miRNAs (AUCs of 0.5–0.9). Significant partial correlations of xanthine and betaine levels and the expression of several miRNAs with BSID-III sub-scales were found. Conclusion: We have identified metabolites/miRNAs that might be useful to support the prediction of middle-term neurodevelopmental outcomes of NE.This study has been funded by Instituto de Salud Carlos III (ISCIII) through the project “RD21/0012/0015” and co-funded by the European Union—NextGenerationEU

Exogenous Application of Salicylic Acid Modulates Oxidative Stress during the Seed Development of Rice (Oryza sativa L.) Grain

The present study aimed to discover the effects of exogenously foliar-applied salicylic acid (SA) in concentrations of 0, 1 and 15 mM (applied 7 and 21 days after heading) on oxidative stress. The effects were monitored through the concentrations of phytoprostanes (PhytoPs) and phytofurans (PhytoFs) in immature and mature grains of three genotypes of rice (‘R52’, ‘R45’ and ‘Yerua’), and their influence on grains per panicle and chalkiness. Chromatographic separation of PhytoPs and PhytoFs was performed using a UHPLC coupled to triple quadrupole-MS/MS (Agilent Technologies, Germany). The concentrations of oxylipins showed differences in both harvest times (immature and mature) for each genotype. The advanced lines, ‘R52’ and ‘R45’, showed concentrations that were 24.0 and 79.0% lower than those of the immature grains, respectively. The PhytoFs concentration in “R45” was 46.0% lower in the mature grains. In unripe grains, SA reduced a single oxylipin of all those analyzed, while in mature grains, a significant decrease in six of the ten monitored biomarkers was observed. The SA produced an increase in grains per panicle, and a decrease in chalkiness. Therefore, salicylic acid-mediated antioxidant regulatory capacities due to oxylipin down-regulation could favor grain filling and, hence, rice productionThis study was partially funded by the “Fundación Séneca de la Región de Murcia” Grupo de Excelencia 19900/GERM/15, and the Spanish project AGL2017-83386-R from the Spanish Ministry of Science, Innovation and Universities. This research is included in the framework of the collaboration between the Spanish Research Council (CEBAS-CSIC) and CNRS-University of Montpellier, as “ProjetsInternationaux de Cooperation Scientifique” (PICS-2015-261141). The authors declare no conflicts of interest. M.M.C.-V.: Instituto Carlos III, Ministry of Economy and Competitiveness, Spain [grant number CD19/00037], and Conselleria de innovación, universidades, ciencia y sociedad digital from GeneralitatValenciana [grant number CIBEST/2021/34]Peer reviewe