Salinity impairs photosynthetic capacity and enhances carotenoid-related gene expression and biosynthesis in tomato (Solanum lycopersicum L. cv. Micro-Tom)

Indexación: ScopusCarotenoids are essential components of the photosynthetic antenna and reaction center complexes, being also responsible for antioxidant defense, coloration, and many other functions in multiple plant tissues. In tomato, salinity negatively affects the development of vegetative organs and productivity, but according to previous studies it might also increase fruit color and taste, improving its quality, which is a current agricultural challenge. The fruit quality parameters that are increased by salinity are cultivar-specific and include carotenoid, sugar, and organic acid contents. However, the relationship between vegetative and reproductive organs and response to salinity is still poorly understood. Considering this, Solanum lycopersicum cv. Micro-Tom plants were grown in the absence of salt supplementation as well as with increasing concentrations of NaCl for 14 weeks, evaluating plant performance from vegetative to reproductive stages. In response to salinity, plants showed a significant reduction in net photosynthesis, stomatal conductance, PSII quantum yield, and electron transport rate, in addition to an increase in non-photochemical quenching. In line with these responses the number of tomato clusters decreased, and smaller fruits with higher soluble solids content were obtained. Mature-green fruits also displayed a salt-dependent higher induction in the expression of PSY1, PDS, ZDS, and LYCB, key genes of the carotenoid biosynthesis pathway, in correlation with increased lycopene, lutein, _- carotene, and violaxanthin levels. These results suggest a key relationship between photosynthetic plant response and yield, involving impaired photosynthetic capacity, increased carotenoid-related gene expression, and carotenoid biosynthesis.https://peerj.com/articles/9742

Stomata regulation by tissue-specific expression of the Citrus sinensis MYB61 transcription factor improves water-use efficiency in Arabidopsis

Water-use efficiency (WUE) is a quantitative measurement of biomass produced per volume of water transpired by a plant. WUE is an important physiological trait for drought response to mitigate the water deficiency. In this work, a cisgenic construction from Citrus sinensis was developed and its function in the improvement of WUE was evaluated in Arabidopsis. Sequences of the CsMYB61 coding region, a transcription factor implicated in the closure of stomata, together with a putative stomata-specific promoter from CsMYB15, were identified and cloned. The protein encoded in the CsMYB61 locus harbors domains and motifs characteristic of MYB61 proteins. In addition, a 1.2 kb promoter region of the gene CsMYB15 (pCsMYB15) containing regulatory elements for expression in guard cells and in response to Abscisic Acid (ABA) and light was isolated. In Arabidopsis, pCsMYB15 directs the expression of the reporter gene GUS in stomata in the presence of light. In addition, transgenic lines expressing the CsMYB61 coding region under transcriptional control of pCsMYB15 have a normal phenotype under in vitro and greenhouse conditions. These transgenic lines exhibited a smaller opening of the stomata pore, lower stomatal conductance and respiration rate, enhanced sensitivity to exogenous ABA, and high drought stress tolerance. Our results indicate that stomata-specific expression of CsMYB61 enhances water use efficiency under drought conditions in Arabidospi

Environmental effects of ozone depletion, UV radiation and interactions with climate change : UNEP Environmental Effects Assessment Panel, update 2017

Peer reviewe

Contribution to the study of taxis in interrupted and alternating currents

International audienc

Contribution a l'etude des taxies en courant interrompu et alternatif

International audienc

Insuffisance rénale chronique: quel régime [Chronic renal failure: what diet?].

A low protein diet has been traditionally advocated in patients with chronic renal failure (CRF), in order to slow its progression. However, CRF is often associated with malnutrition, aggravating its prognosis, especially in elderly patients. In severe CRF, the spontaneous reduction of appetite coupled with additional restrictions regarding sodium, potassium and phophates may further impact on nutrition status. The potential benefit of a low protein diet is therefore questionable. We only recommend a moderately restricted protein diet (0,8 g/kg/day) in selected patients with no sign of malnutrition. This strategy, if applied, must be supported by a multidisciplinary approach involving a nephrologist and a specialised dietician. Additional dietary restrictions are not justified, except in particular situations

Dénutrition en diatlyse: vers la fin d'une fatalité [Malnutrition on dialysis: the end of a fatality].

Protein-energy malnutrition in patients treated with haemodialysis (HD) is a complex, multifactorial and prevalent problem, starting well ahead of the dialysis program. It is associated with an increased morbidity and mortality. Uraemic patients are relatively resistant to nutrients because of metabolism abnormalities. Prevention of malnutrition is therefore more efficient than treatment per se. Classical supplementation including oral nutritional supplements, intradialytic parenteral nutrition and enteral nutrition remain efficient, if applied for a sufficient time. A global approach coupling supplementation and strategies designed to optimise metabolism abnormalities should increase treatment efficacy and improve the outcome and quality of life of these patients

Dénutrition en diatlyse: vers la fin d'une fatalité [Malnutrition on dialysis: the end of a fatality].

Protein-energy malnutrition in patients treated with haemodialysis (HD) is a complex, multifactorial and prevalent problem, starting well ahead of the dialysis program. It is associated with an increased morbidity and mortality. Uraemic patients are relatively resistant to nutrients because of metabolism abnormalities. Prevention of malnutrition is therefore more efficient than treatment per se. Classical supplementation including oral nutritional supplements, intradialytic parenteral nutrition and enteral nutrition remain efficient, if applied for a sufficient time. A global approach coupling supplementation and strategies designed to optimise metabolism abnormalities should increase treatment efficacy and improve the outcome and quality of life of these patients

Proteomics fingerprinting of phagosome maturation and evidence for the role of a Galpha during uptake.

Phagocytosis, whether of food particles in protozoa or bacteria and cell remnants in the metazoan immune system, is a conserved process. The particles are taken up into phagosomes, which then undergo complex remodeling of their components, called maturation. By using two-dimensional gel electrophoresis and mass spectrometry combined with genomic data, we identified 179 phagosomal proteins in the amoeba Dictyostelium, including components of signal transduction, membrane traffic, and the cytoskeleton. By carrying out this proteomics analysis over the course of maturation, we obtained time profiles for 1,388 spots and thus generated a dynamic record of phagosomal protein composition. Clustering of the time profiles revealed five clusters and 24 functional groups that were mapped onto a flow chart of maturation. Two heterotrimeric G protein subunits, Galpha4 and Gbeta, appeared at the earliest times. We showed that mutations in the genes encoding these two proteins produce a phagocytic uptake defect in Dictyostelium. This analysis of phagosome protein dynamics provides a reference point for future genetic and functional investigations

Early induction of Fe-SOD gene expression is involved in tolerance to Mn toxicity in perennial ryegrass

Manganese (Mn) toxicity limits plant growth in acid soils. Although Mn toxicity induces oxidative stress, the role of superoxide dismutase (SOD, EC.1.15.1.1) isoforms in conferring Mn tolerance remains unclear. Seedlings of ryegrass cultivars Nui (Mn-sensitive) and Kingston (Mn-tolerant) were hydroponically grown at 2.4 (optimal) or 750 mu M Mn (toxic) concentration, and harvested from 2 to 48 h. Kingston showed higher shoot Mn than Nui at 2.4;mu M Mn. At toxic supply, shoot Mn concentration steadily increased in both cultivars, with Kingston having the highest accumulation at 48 h. An early (2 h) increase in lipid peroxidation under Mn excess occurred, but it returned (after 6 h) to the basal level in Kingston only. Kingston exhibited higher SOD activity than Nui, and that difference increased due to toxic Mn. In general, Mn-induced gene expression of Mn- and Cu/Zn-SOD isoforms was higher in Nui than Kingston. Nevertheless, under Mn excess, we found a greater Fe-SOD up-regulation (up to 5-fold) in Kingston compared to Nui. Thus, Fe-SOD induction in Kingston might explain, at least partly, its high tolerance to Mn toxicity. This is the first evidence that Mn toxicity causes differential gene expression of SOD isoforms in ryegrass cultivars in the short-term. (C) 2013 Published by Elsevier Masson SAS