Estrés Abiótico y Homeostasis Iónica

Master Universitario en Biología Agraria y Acuicultura.-- 75 horas, 3 Créditos ECTS.Peer reviewe

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Lipoxygenase activity and lipid composition of cotyledons and oil bodies of two sunflower hybrids

Lipoxygenase (linoleate: oxygen oxidoreductase, EC 1.13.11.12) and lipid fatty acid composition of cotyledons and oil bodies of two near-isogenic high and low oleic acid sunflower hybrids (Helianthus annuus L.) were investigated during seedling growth. Triacylglycerol fatty acid content decreased strongly in cotyledons of both hybrids between days 1 and 7 of seedling growth. Oil bodies contained mostly neutral lipids and small amounts of phospholipids and proteins. Between days 1 and 7 of germination the degradation rate of oil body neutral lipids was lower for the high oleic acid hybrid compared to the low oleic acid hybrid. From days 0 to 9 of germination, neutral lipids and phospholipids of cotyledons and oil bodies from the high oleic acid hybrid contained more oleic acid and less linoleic acid than those of the low oleic acid hybrid. The presence of an oil body lipoxygenase was shown enzymatically and by immunodetection. In both hybrids, lipoxygenase activity of oil bodies and whole cotyledons was lower in 7 than in 1 day-old seedlings. Moreover, the high oleic acid hybrid showed a lower oil body lipoxygenase activity than the low oleic acid hybrid, both at 1 and 7 days of germination. Immunoblot analysis indicated that differences in enzyme activity between the two hybrids were not due to changes in the amount of antigenic protein. Oleic acid was found to be a competitive inhibitor of oil body lipoxygenase. Based on these results it is concluded that oleic acid could act as a natural inhibitor of sunflower oil body lipoxygenase.This work was supported by Spanish DGICYT (Grant PB 94-0118-CO2-01)Peer Reviewe

Improved yield, fruit quality, and salt resistance in tomato co-overexpressing LeNHX2 and SlSOS2 genes

The K, Na/H antiporter LeNHX2 and the regulatory kinase SlSOS2 are important determinants of salt tolerance in tomato plants and their fruit production ability. In this work, we have analyzed the effects of LeNHX2 and SlSOS2 co-overexpression on fruit production, quality in tomato plants (Solanum lycopersicum L. cv. MicroTom), and analyzed physiological parameters related to salt tolerance. Plants overexpressing LeNHX2, SlSOS2 or both were grown in greenhouse. They were treated with 125 mM NaCl or left untreated and their salt tolerance was analyzed in terms of plant biomass and fruit yield. Under NaCl cultivation conditions, transgenic tomato plants overexpressing either SlSOS2 or LeNHX2 or both grew better and showed a higher biomass compared to their wild-type plants. Proline, glucose and protein content in leaves as well as pH and total soluble solid (TSS) in fruits were analyzed. Our results indicate that salinity tolerance of transgenic lines is associated with an increased proline, glucose and protein content in leaves of plants grown either with or without NaCl. Salt treatment significantly reduced yield, pH and TSS in fruits of WT plants but increased yield, pH and TSS in fruits of transgenic plants, especially those overexpressing both LeNHX2 and SlSOS2. All these results indicate that the co-overexpression of LeNHX2 and SlSOS2 improve yield and fruit quality of tomato grown under saline conditions.This work was supported by grants from National Centre for Scientific and Technical Research-CNRST and Minister for Higher Education, Scientific Research and Executive Training— Morocco (PPR/2015/21). Consejería de Economía, Innovación Ciencia y Empresa, Junta de Andalucía, Spain (CVI-7558 to MPRR), Spanish Ministry of Economy and Competitiveness and Agencia Estatal de Investigación (BIO2015-65056-P, BIO2016-81957-REDT/ AEI and Programa I-COOPB + 2013 Ref: COOPB20053)

Plastidial transporters KEA1 and KEA2 at the inner envelope membrane adjust stromal pH in the dark

Photosynthesis and carbon fixation depend critically on the regulation of pH in chloroplast compartments in the daylight and at night. While it is established that an alkaline stroma is required for carbon fixation, it is not known how alkaline stromal pH is formed, maintained or regulated. We tested whether two envelope transporters, AtKEA1 and AtKEA2, directly affected stromal pH in isolated Arabidopsis chloroplasts using the fluorescent probe 2ʹ,7ʹ-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF). External K-induced alkalinization of the stroma was observed in chloroplasts from wild-type (WT) plants but not from kea1kea2 mutants, suggesting that KEA1 and KEA2 mediate K uptake/H loss to modulate stromal pH. While light-stimulated alkalinization of the stroma was independent of KEA1 and KEA2, the rate of decay to neutral pH in the dark is delayed in kea1kea2 mutants. However, the dark-induced loss of a pH gradient across the thylakoid membrane was similar in WT and mutant chloroplasts. This indicates that proton influx from the cytosol mediated by envelope K/H antiporters contributes to adjustment of stromal pH upon light to dark transitions.This work was supported by ERDF cofinanced grants from the Spanish Agencia Estatal de Investigación, Ministerio de Economía y Competitividad/Ministerio de Ciencia e Innovación (BIO2015-65056-P, PID2019-105260GB-I00 and BIO2016-81957-REDT/AEI to KV and MPRR) and from the Consejería de Conocimiento, Investigación y Universidad, Junta de Andalucía, Spain (CVI-7558 to MPRR), and stimulated by the ERA-CAPS funded project Flux4Lives

La sobreexpresión de SlSOS2 confiere tolerancia a la salinidad en tomate transgénico

Trabajo presentado en el XII Congreso Hispano-Luso de Fisiología Vegetal, celebrado en Castellón del 21 al 24 de junio de 2011.La ruta SOS dependiente de Ca2+ se ha revelado como un mecanismo esencial en la homeostasis del Na+ y K+, así como del transporte de Na+ a larga distancia en plantas de Arabidopsis, Thellungiella y tomate cultivadas bajo condiciones salinas. Aquí, se describe la caracterización funcional del gen que codifica a la proteína quinasa en la ruta SOS en tomate, SlSOS2. La secuencia aminoacídica de SlSOS2 mostró la mayor homología (71% de identidad) con AtSOS2 (AtCIPK24), de entre todas las CIPKs de Arabidopsis. La expresión heteróloga de SlSOS2 tanto en levadura como en el mutante de Arabidopsis sos2, en ensayos de complementación funcional de sensibilidad a sal, mostraron que era el homólogo funcional de la proteína AtSOS2. Para evaluar su papel en la tolerancia del tomate a la salinidad se han obtenido plantas transgénicas de S. lycopersicum cv. MicroTom mono-locus y homocigóticas para el transgen SlSOS2, bajo control del promotor constitutivo 35S. La sobreexpresión de SlSOS2 incrementó la tolerancia a la salinidad de las plantas de tomate, tanto en estadíos muy jóvenes de desarrollo en ausencia de transpiración como en estadios de desarrollo vegetativo en condiciones de transpiración. Esta mayor tolerancia de las de las plantas transgénicas se manifestó en un menor contenido de sodio en raíces y tallos, menor clorosis foliar, una mayor velocidad de crecimiento relativo y una floración más temprana que permitió, en última instancia, una mayor producción de frutos. A nivel bioquímico, el incremento en la tolerancia a la salinidad de las plantas sobrexpresoras de SlSOS2 estuvo asociado principalmente a la regulación positiva de los antiportadores Na+/H+ de la membrana plasmática (SlSOS1) y de los antiportadores K+,Na+/H+ de los compartimentos endosomal-vacuolar (LeNHX2 y LeNHX4), responsables, en gran medida, del mantenimiento de la homeostasis celular de Na+ y K+.Financiado por MCINN y fondos FEDER (BIO2006-01955), BIO2008-01691, BIO-2009-07655) y CICE, Junta de Andalucía (AGR-436).Peer Reviewe

Gibberellic acid and indole acetic acid improves salt tolerance in transgenic tomato plants overexpressing LeNHX4 antiporter

Salinity is the major environmental factor that limits plant growth and productivity. High concentrations of Na and Cl ions in soil solution negatively affect K uptake and may cause physiological and metabolic disorders, which adversely affect the plant growth and crop yield. In plants, NHX antiporters play an important role in salt tolerance by catalyzing Na accumulation in vacuoles. In this work, we studied the effect of exogenous plants hormones auxin (IAA) and gibberellic acid (GA), on salinity tolerance, fruit production and quality in transgenic tomato plants overexpressing LeNHX4 antiporter grown under 125 mM NaCl. Here, we have found that IAA and GA positively affected leaf proline, glucose, soluble proteins and ortho-diphenol. In addition, both hormones increased tomato production and fruit quality parameters. These results suggest that GA and IAA improved salinity tolerance and increased fruit yield and quality, probably by increasing the expression or the activity of LeNHX4 antiporter.This work was supported by grants from National Centre for Scientific and Technical Research and Minister for Higher Education, Scientific Research and Executive Training (Morocco) Ref: PPR/2015/21. CSIC Progamme for scientific cooperation for development (I-COOP-B + 2013; Ref: COOPB20053

Overexpression of LeNHX2 and SlSOS2 increases salt tolerance and fruit production in double transgenic tomato plants

Transgenic tomato plants (Solanum lycopersicum L. cv. MicroTom) overexpressing both the K,Na/H antiporter LeNHX2 and the regulatory kinase SlSOS2 were produced by crossing transgenic homozygous lines overexpressing LeNHX2 and SlSOS2. LeNHX2 expression was enhanced in plants overexpressing LeNHX2 but surprisingly even more in plants overexpressing SlSOS2 with and without LeNHX2. All transgenic plants showed better NaCl tolerance than wild type controls and plants overexpressing both LeNHX2 and SlSOS2 grew better under saline conditions than plants overexpressing only one of these genes. Yield related parameters indicated that single and above all double transgenic plants performed significantly better than wild type controls. All transgenic plants produced fruits with a higher K content than wild-type plants and plants overexpressing SlSOS2 accumulated more Na in fruits than the rest of the plants when grown with NaCl. Roots, stems and leaves of transgenic plants overexpressing LeNHX2 showed a higher K content than wild type and single transgenic plants overexpressing SlSOS2. Na content in stems and leaves of NaCl treated plants was higher in SlSOS2 overexpressing plants than in wild type and LeNHX2 single transgenic plants. All transgenic lines showed a higher leaf relative water content and a higher plant water content and water use efficiency than wild type controls when both were grown in the presence of NaCl. Results in this work indicate that the joint overexpression of LeNHX2 and SlSOS2 improves growth and water status under NaCl stress, affects K and Na homeostasis and enhances fruit yield of tomato plants.This work was supported by grants from Consejería de Economía, Innovación, Ciencia y Empresa, Junta de Andalucía, Spain (CVI-7558 to MPRR), Spanish MINECO and Agencia Estatal de Investigación (BIO2015-65056-P and BIO2016-81957-REDT/AEI to KV and MPRR) and Moroccan MESRSFC and CNRST (PPR/2015/21 to MB).Peer Reviewe