Tolerance to Stress Combination in Tomato Plants: New Insights in the Protective Role of Melatonin.

Abiotic stresses such as drought, heat or salinity are major causes of yield loss worldwide. Recent studies have revealed that the acclimation of plants to a combination of different environmental stresses is unique and therefore cannot be directly deduced from studying the response of plants to each of the different stresses applied individually. The efficient detoxification of reactive oxygen species (ROS) is thought to play a key role in enhancing the tolerance of plants to abiotic stresses. Here, we report on the role of melatonin in the protection of the photosynthetic apparatus through the increase in ROS detoxification in tomato plants grown under the combination of salinity and heat, two of the most common abiotic stresses known to act jointly. Plants treated with exogenous melatonin showed a different modulation in the expression on some antioxidant-related genes and their related enzymes. More specifically, ascorbate peroxidase, glutathione reductase, glutathione peroxidase and phospholipid hydroperoxide glutathione peroxidase (APX, GR, GPX and Ph-GPX, resepctively) showed an antagonistic regulation as compared to plants that did not receive melatonin. This translated into a better antioxidant capacity and to a lesser ROS accumulation under stress combination. The performance of the photosynthesis parameters and the photosystems was also increased in plants treated with exogenous melatonin under the combination of salinity and heat. In accordance with these findings, tomato plants treated with melatonin were found to grow better under stress combination that the non-treated ones. Our study highlights the important role that exogenous melatonin plays in the acclimation of plants to a combination of two different abiotic stresses, and how this compound can specifically regulate oxidative stress-related genes and enzymes to increase plant tolerance.

A splice acceptor site mutation in TaGW2-A1 increases thousand grain weight in tetraploid and hexaploid wheat through wider and longer grains.

KEY MESSAGE: Across 13 experiments the gw2 - A1 mutant allele shifts grain size distribution consistently across all grains significantly increasing grain weight (6.6 %), width (2.8 %) and length (2.1 %) in tetraploid and hexaploid wheat. There is an urgent need to identify, understand and incorporate alleles that benefit yield in polyploid wheat. The rice OsGW2 gene functions as a negative regulator of grain weight and width and is homologous to the wheat TaGW2 gene. Previously it was shown that transcript levels of the A-genome homoeologue, TaGW2-A1, are negatively associated with grain width in hexaploid wheat. In this study we screened the tetraploid Kronos TILLING population to identify mutants in TaGW2-A1. We identified a G to A transition in the splice acceptor site of exon 5 which leads to mis-splicing in TaGW2-A1. We backcrossed the mutant allele into tetraploid and hexaploid wheat and generated a series of backcross derived isogenic lines which were evaluated in glasshouse and field conditions. Across 13 experiments the GW2-A1 mutant allele significantly increased thousand grain weight (6.6 %), grain width (2.8 %) and grain length (2.1 %) in tetraploid and hexaploid wheat compared to the wild type allele. In hexaploid wheat, this led to an increase in spike yield since no differences were detected for spikelet or grain number between isogenic lines. The increase in grain width and length was consistent across grains of different sizes, suggesting that the effect of the mutation is stable across the ear and within spikelets. Differences in carpel size and weight between alleles were identified as early as 5 days before anthesis, suggesting that TaGW2-A1 acts on maternal tissue before anthesis to restrict seed size. A single nucleotide polymorphism marker was developed to aid the deployment of the mutant allele into breeding programmes.

Metabolite profile of the tomato dwarf cultivar Micro-Tom and comparative response to saline and nutritional stresses with regard to a commercial cultivar.

BACKGROUND: The dwarf tomato variety Micro-Tom has been used as a plant model for studies of plant development. However, its response to environmental and agricultural factors has not been well studied. This work studies the phytochemical content of Micro-Tom tomato and its comparative response to saline and nutritional (N, K and Ca) stresses with regard to a commercial variety. RESULTS: The chromatographic profiles of Micro-Tom were similar to those of the commercial variety and the only differences appear to be the concentration of the components. In Micro-Tom, the concentrations of sugars and organic acids increased by salinity in a lesser extent than in Optima. Moreover, contrary to that observed in the commercial variety, phenolic compounds and vitamin C did not increase by salinity in the dwarf variety. However, both varieties increased similarly the concentrations of carotenoids under saline conditions. Finally, fruit yield and most primary and secondary metabolite concentrations in Micro-Tom were not affected by N, K or Ca limitation. CONCLUSIONS: The mutations leading to the dwarf phenotype did not greatly alter the metabolite profiles but studies using Micro-Tom as a plant model should consider the lower capacity for sugars and organic acids under saline conditions and the greater tolerance to nutrient limitation of the dwarf variety.

The combined effect of salinity and heat reveals a specific physiological, biochemical and molecular response in tomato plants.

Many studies have described the response mechanisms of plants to salinity and heat applied individually; however, under field conditions some abiotic stresses often occur simultaneously. Recent studies revealed that the response of plants to a combination of two different stresses is specific and cannot be deduced from the stresses applied individually. Here, we report on the response of tomato plants to a combination of heat and salt stress. Interestingly, and in contrast to the expected negative effect of the stress combination on plant growth, our results show that the combination of heat and salinity provides a significant level of protection to tomato plants from the effects of salinity. We observed a specific response of plants to the stress combination that included accumulation of glycine betaine and trehalose. The accumulation of these compounds under the stress combination was linked to the maintenance of a high K(+) concentration and thus a lower Na(+) /K(+) ratio, with a better performance of the cell water status and photosynthesis as compared with salinity alone. Our findings unravel new and unexpected aspects of the response of plants to stress combination and provide a proposed list of enzymatic targets for improving crop tolerance to the abiotic field environment.

Physiological, phytochemical and structural changes of multi-leaf lettuce caused by salt stress.

BACKGROUND: Environmental stress due to salt has been described to enhance lettuce processability, shelf life and consumer acceptability. Moderate salinity causes altered leaf carotenoid, lignin, phenolic and flavonol levels without noticeable changes in the green colour and morphology of lettuce. The aim of this study was to understand the improvements in processability, due to salt stress, related to textural properties and structural characteristics. RESULTS: Physiological, phytochemical and structural changes were observed that were of significant relevance to salt stress (50, 100 and 150 mmol L(-1) NaCl). Fresh weight per plant, fresh weight per leaf, leaf area, water content, colour saturation, chlorophyll a and b and the area of the intercellular spaces decreased when the concentration of salt was increased. Solute concentration, elasticity, total and individual phenolic acids and the areas occupied by the palisade and spongy parenchyma cells increased when the concentration of salt was increased. CONCLUSION: These data illustrate that salt stress can have a positive impact on certain structural parameters, especially tissue elasticity, that can be closely linked to a higher number of cells, of lower size and high leaf strength, explaining the postharvest longevity of lettuce. However, leaf growth and visual quality could be negatively affected by salt stress.

Family Self-Care in Chronic Disease Management: An Evolving Care Pattern?

Introduction: Self-care emerges in the family context, despite being seen as an individual determinant of health. The family, understood as a system and social unit, converges to a pattern of self-care and not to a sum of it, assuming relevance at certain moments of the life cycle, particularly in the management of chronic disease. Purpose: To perform the transposition of individual self-care to the family self-care, considering the current family's needs and characteristics, by adopting family self-care as the core concept of a care pattern as a determinant of family health. Conclusion: The family unit is the most influential factor in the health status of individuals, and it will be through family self-care behaviors that families can be healthier by managing their diseases more effectively. They seek to achieve family health, maintaining health through health promotion and disease management practices, always mediated by family self-care behaviors.

Impact of family-centered care in families with children with intellectual disability: A systematic review.

Background: Family-Centered Care (FCC) is an approach to healthcare planning, delivery and evaluation, based on beneficial partnerships between health professionals, patients and families. FCC may be particularly relevant for families with children with intellectual disability (ID), given their needs of continuum care. Objective: To identify which components of the FCC are practiced and which health outcomes are considered effective in families with children with ID. Method: A systematic review guided by the PRISMA STATEMENT 2020 approach and the STROBE reporting guidelines was performed on specific databases through the EBSCOhost Web platform: MEDLINE with Full Text, CINAHL PLUS with Full Text, Academic Search Complete and Psychology and Behavioral Sciences Collection. Peer-reviewed articles published in English or Portuguese languages from 2018 to September 2023 were retrieved. Methodological quality was established using the Quality Assessment Tool for Observational, Cohort and Cross-Sectional Studies - NHLBI, NIH. Results: Ten studies met the eligibility criteria and were synthetized. The results revealed nine components, reflecting the way FCC was developed: shared decision-making; family education; respect for culture; family engagement; recognition of the family's needs, characteristics and interests; specialized care support; social and emotional support; family functionality; and family seen as a unit. The health outcomes demonstrate effective gains in improving children's health through family satisfaction with health services. Also achieved psychological and social benefits, with improved family well-being and quality of life, favoring family empowerment. Conclusions: The evidence suggests that FCC components involves an effective partnership between the family and health professionals as the main key in developing care plans, as well as the experience that the family unit brings to the delivery of care. FCC approach include all family members as decision-makers, providing emotional, physical and instrumental levels of support. Health outcomes emerged in three strands; for children with ID, families and health services.

Prophylactic negative pressure wound therapy in patients with closed surgical wound: An integrative review.

Surgical site infection is the leading healthcare-associated infection and a major contributor to rising healthcare costs. Implementation of measures to reduce this problem, particularly the prophylactic use of negative pressure wound therapy, may be an effective and promising method to reduce the risk of surgical site infection in patients with closed surgical wounds. The aim of the study was to identify the effectiveness of negative pressure wound therapy as a prophylactic measure in reducing the risk of surgical site infection in patients with a closed surgical wound. Whittemore and Knafl's five-step integrative review framework was carried out using three electronic databases. MEDLINE with Full-text, CINAHL with Full-text and Academic Search Complete were searched through the EBSCOhost Web platform. Articles search publication date was between 2018 and 2022. Nine studies were identified that addressed the effectiveness of prophylactic negative pressure wound therapy in reducing the risk of surgical site infection in the patient with a closed surgical wound. There was also evidence of effectiveness in reducing surgical wound dehiscence, drainage output and drainage time, as well as reducing the incidence of hospital readmissions and the need for wound debridement. Prophylactic negative pressure wound therapy can be an effective treatment option, among others, in reducing the risk of surgical site infection in patients with a closed surgical wound. This evidence promotes improved clinical practice regarding the management of the closed surgical wound, promoting health gains for patients.

Health Promotion and Disease Prevention in the Elderly: The Perspective of Nursing Students.

Health promotion and disease prevention are closely linked to health literacy. Therefore, intervention to increase individuals' knowledge is essential if action is to be taken to promote a healthy lifestyle with support from health professionals for decision making on choices leading to behavioral change. Taking into account the growing aging population, nurses and nursing students have to develop interventions to promote health and prevent disease in these people, in order to keep them healthy and with quality of life. This study aims to understand how nursing students' experiences in a clinical teaching context contributed to the development of their competencies in the promotion of health and prevention of disease in the elderly. METHOD: Qualitative, exploratory, and descriptive study carried out with ten students about to finish a graduate nursing course in a higher education institution in the South of Portugal. This study was carried out through narratives, one of the most common data collection procedures in social and health investigations. The content analysis technique, more specifically the thematic categorical analysis, was used for data analysis. The study received authorization from the Ethics Committee of the institution where it took place. RESULTS: Three categories were found: "Strategies to promote health and prevent disease in the elderly", "Health improvements from the implementation of the strategies to promote health and prevent disease in the elderly", and "The impact your participation in these strategies to promote health and prevent disease in the elderly had on your formative process". CONCLUSION: The students developed competencies during their clinical teaching experiences through the implementation of strategies of health promotion and disease prevention adapted to/focused on the needs of the elderly.

Phenolic and Carotenoid Profile of Lamb's Lettuce and Improvement of the Bioactive Content by Preharvest Conditions.

This study characterizes the phenolic, carotenoid and chlorophyll profile of lamb's lettuce, a vegetable whose consumption in salads and ready-to-eat products is constantly growing. The MS/MS analysis allowed the identification of thirty-five phenolic compounds including hydroxybenzoic and hydroxycinnamic acids, flavanones, flavanols and flavanones, many of which are reported here in lamb's lettuce for the first time. Chlorogenic acid was the principal phenolic compound found (57.1% of the total phenolic concentration) followed by its isomer cis-5-caffeoylquinic. Other major phenolic compounds were also hydroxycinnamic acids (coumaroylquinic, dicaffeoylquinic and feruloylquinic acids) as well as the flavones luteolin-7-rutinoside, diosmetin-apiosylglucoside and diosmin. Regarding carotenoids, seven xanthophyll and four carotenes, among which ß-carotene and lutein were the major compounds, were detected from their UV-Vis absorption spectrum. In addition, chlorophylls a and b, their isomers and derivatives (pheophytin) were identified. Preharvest factors such as reduced fertilization levels or salinity increased some secondary metabolites, highlighting the importance of these factors on the final nutritional value of plant foods. Lamb's lettuce was seen to be a good potential source of bioactive compounds, and fertilization management might be considered a useful tool for increasing its nutritional interest.

Amelioration of the Oxidative Stress Generated by Simple or Combined Abiotic Stress through the K⁺ and Ca2+ Supplementation in Tomato Plants.

Abiotic stressors such as drought, heat, or salinity are major causes of yield loss worldwide due to the oxidative burst generated under these conditions. Recent studies have revealed that plant response to a combination of different environmental stressors is unique and cannot be deduced from the response developed to each stress when applied individually. Some studies have demonstrated that a different management of some nutrients in the irrigation solution may provide an advantage to the plants against abiotic stressors. Thus, the aim of this study was to investigate if an increase in potassium (K⁺) and calcium (Ca2+) concentration in the nutrient solution may have a positive effect on the amelioration of oxidative stress which occurs under the combination of salinity and heat in tomato plants. Our results indicated that plants irrigated with an increase in K⁺ and Ca2+ concentrations in the irrigation solution from 7mM (K⁺) to 9.8 mM and from 4 mM (Ca2+) to 5.6 mM, respectively, induced a recovery of the biomass production compared to the plants treated with salinity or salinity + heat, and subsequently irrigated with the regular Hoagland solution. This was correlated with a better performance of all the photosynthetic parameters, a reduction in the foliar concentration of H2O2 and a lower lipid peroxidation rate, and with a better performance of the antioxidant enzymes ascorbate peroxidase ascorbate peroxidase (APX), dehydroascorbate reductactase (DHAR), glutathione reductase (GR), and NADPH oxidase. Our results showed that these enzymes were differentially regulated at the transcriptional level, showing a higher reactive oxygen species (ROS) detoxification efficiency under salinity and under the combination of salinity and heat, as compared to those plants irrigated with common Hoagland. An increase in K⁺ and Ca2+ in the irrigation solution also induced a lower Na+ accumulation in leaves and a higher K⁺/Na⁺ ratio. Thus, our study highlights the importance of the right management of the plant nutritional status and fertilization in order to counteract the deleterious effects of abiotic stress in plants.

Accumulation of Flavonols over Hydroxycinnamic Acids Favors Oxidative Damage Protection under Abiotic Stress.

Efficient detoxification of reactive oxygen species (ROS) is thought to play a key role in enhancing the tolerance of plants to abiotic stresses. Although multiple pathways, enzymes, and antioxidants are present in plants, their exact roles during different stress responses remain unclear. Here, we report on the characterization of the different antioxidant mechanisms of tomato plants subjected to heat stress, salinity stress, or a combination of both stresses. All the treatments applied induced an increase of oxidative stress, with the salinity treatment being the most aggressive, resulting in plants with the lowest biomass, and the highest levels of H2O2 accumulation, lipid peroxidation, and protein oxidation. However, the results obtained from the transcript expression study and enzymatic activities related to the ascorbate-glutathione pathway did not fully explain the differences in the oxidative damage observed between salinity and the combination of salinity and heat. An exhaustive metabolomics study revealed the differential accumulation of phenolic compounds depending on the type of abiotic stress applied. An analysis at gene and enzyme levels of the phenylpropanoid metabolism concluded that under conditions where flavonols accumulated to a greater degree as compared to hydroxycinnamic acids, the oxidative damage was lower, highlighting the importance of flavonols as powerful antioxidants, and their role in abiotic stress tolerance.

Glutathione homeostasis as an important and novel factor controlling blossom-end rot development in calcium-deficient tomato fruits.

Based on previous results in which oxidative metabolism was suggested as a possible inducer of blossom-end rot (BER), the main questions addressed here were whether calcium deficiency is the main factor that induces BER or whether this physiological disorder a general stress-related phenomenon? Tomato plants were grown under optimal or deficient calcium concentrations. Only the application of 0.1mM calcium resulted in BER induction, although only half of the fruits grown under this treatment had this disorder. Having fruits showing or not showing BER in the same plant and treatment provided us with a powerful tool that we used to investigate whether calcium deficiency operates alongside another mechanism in the induction of BER. Whether or not this other mechanism was the one controlling BER incidence was also investigated. We performed a complete study of the oxidative metabolism in the pericarp of healthy fruits and in the healthy portion of BER-affected fruits. Calcium deficiency led to an induction of NADPH oxidase, superoxide dismutase, dehydro- and monodehydroascorbate reductase, and to an inhibition of catalase, ascorbate peroxidase and glutathione reductase, with a concomitant accumulation of hydrogen peroxide and an increase in lipid peroxidation. While the ascorbate redox state was not affected by calcium deficiency, the glutathione redox state was markedly reduced. We conclude that calcium deficiency fundamentally affected the activity of the ascorbate-glutathione enzymes, with special importance to the inhibition of GR, which lead to a reduction of the glutathione redox state. This could cause the breakdown of cellular homeostasis, the inhibition of other enzymes responsible for H(2)O(2) detoxification, and ultimately an increase of lipid peroxidation. Therefore, BER is defined here as the visual symptom of a massive lipid peroxidation event caused by the breakdown of cellular glutathione homeostasis.