Identification of key genes involved in the phenotypic alterations of res (restored cell structure by salinity) tomato mutant and its recovery induced by salt stress through transcriptomic analysis.

BACKGROUND: The res (restored cell structure by salinity) mutant, recently identified as the first tomato mutant accumulating jasmonate in roots under non-stressful conditions, exhibits a remarkable growth inhibition and morphological alterations in roots and leaves, which are suppressed when the mutant plants are exposed to salinity. In order to understand the molecular basis of the phenotype recovery induced by salt stress in the res mutant, we carried out a comparative transcriptomic analysis in roots and leaves of wild-type and res plants in absence of stress (control) and when the phenotypic recovery of res mutant began to be observed upon salt stress (5 days of 200 mM NaCl). RESULTS: The number of differentially expressed genes was three times greater in roots than in leaves of res vs WT plants grown in control, and included the down-regulation of growth-promoting genes and the up-regulation of genes involved in Ca2+ signalling, transcription factors and others related to stress responses. However, these expression differences were attenuated under salt stress, coinciding with the phenotypic normalisation of the mutant. Contrarily to the attenuated response observed in roots, an enhanced response was found in leaves under salt stress. This included drastic expression changes in several circadian clock genes, such as GIGANTEA1, which was down-regulated in res vs WT plants. Moreover, the higher photosynthetic efficiency of res leaves under salt stress was accompanied by specific salt-upregulation of the genes RUBISCO ACTIVASE1 and ALTERNATIVE OXIDASE1A. Very few genes were found to be differentially expressed in both tissues (root and leaf) and conditions (control and salt), but this group included SlWRKY39 and SlMYB14 transcription factors, as well as genes related to protein homeostasis, especially protease inhibitors such as METALLOCARBOXYPEPTIDASE INHIBITOR, which also seem to play a role in the phenotype recovery and salt tolerance of res mutant. CONCLUSIONS: In summary, in this study we have identified genes which seem to have a prominent role in salt tolerance. Moreover, we think this work could contribute to future breeding of tomato crops with increased stress tolerance.

Social Networking Use Across Gender: Its Association with Social Connectedness and Happiness Amidst the COVID-19 Pandemic.

With the increasing popularity of social networking platforms, it serves a greater purpose that is no longer contained simply as a means of social leisure. Social networking sites (SNSs) form and maintain social interactions. Various phenomena revolve around how this usage is associated with certain behaviors, such as keeping social ties online and affecting well-being. It is vital to understand how SNSs may affect users differently during this time, viewing this in the context of the COVID-19 pandemic in the Philippines. Moreover, studies have also suggested that gender plays a role in these behaviors. The present study investigated SNS use and showed evidence of its association with social connectedness and happiness across gender during the COVID-19 pandemic. We empirically examined the association of social networking use with the sense of social connectedness and state of happiness among 420 Generation Z Filipinos (31.4% male) aged 18 to 27. We found that social networking use is not associated with either social connectedness or happiness. Multiple-sample path analysis was performed to investigate further the association between social networking site use, social connectedness, and happiness across gender. SNS use for male participants during stress-related periods predicted decreased social connectedness and happiness levels. General motives for use, or reasons people are likely to use SNSs, also predicted reduced happiness levels among males. Overall, the findings suggest that SNS use by itself may not be sufficient to influence substantial change in social connectedness and happiness and that gender alter the ways of SNS use, given its importance as a crucial channel for communication at the time of the COVID-19 pandemic.

An insertional mutagenesis programme with an enhancer trap for the identification and tagging of genes involved in abiotic stress tolerance in the tomato wild-related species Solanum pennellii.

Salinity and drought have a huge impact on agriculture since there are few areas free of these abiotic stresses and the problem continues to increase. In tomato, the most important horticultural crop worldwide, there are accessions of wild-related species with a high degree of tolerance to salinity and drought. Thus, the finding of insertional mutants with other tolerance levels could lead to the identification and tagging of key genes responsible for abiotic stress tolerance. To this end, we are performing an insertional mutagenesis programme with an enhancer trap in the tomato wild-related species Solanum pennellii. First, we developed an efficient transformation method which has allowed us to generate more than 2,000 T-DNA lines. Next, the collection of S. pennelli T(0) lines has been screened in saline or drought conditions and several presumptive mutants have been selected for their salt and drought sensitivity. Moreover, T-DNA lines with expression of the reporter uidA gene in specific organs, such as vascular bundles, trichomes and stomata, which may play key roles in processes related to abiotic stress tolerance, have been identified. Finally, the growth of T-DNA lines in control conditions allowed us the identification of different development mutants. Taking into account that progenies from the lines are being obtained and that the collection of T-DNA lines is going to enlarge progressively due to the high transformation efficiency achieved, there are great possibilities for identifying key genes involved in different tolerance mechanisms to salinity and drought.

Unraveling the Strategies Used by the Underexploited Amaranth Species to Confront Salt Stress: Similarities and Differences With Quinoa Species.

Yield losses due to cultivation in saline soils is a common problem all over the world as most crop plants are glycophytes and, hence, susceptible to salt stress. The use of halophytic crops could be an interesting alternative to cope with this issue. The Amaranthaceae family comprises by far the highest proportion of salt-tolerant halophytic species. Amaranth and quinoa belong to this family, and their seeds used as pseudo-cereal grains have received much attention in recent years because of their exceptional nutritional value. While advances in the knowledge of salt tolerance mechanisms of quinoa have been remarkable in recent years, much less attention was received by amaranth, despite evidences pointing to amaranth as a promising species to be grown under salinity. In order to advance in the understanding of strategies used by amaranth to confront salt stress, we studied the comparative responses of amaranth and quinoa to salinity (100 mM NaCl) at the physiological, anatomical, and molecular levels. Amaranth was able to exhibit salt tolerance throughout its life cycle, since grain production was not affected by the saline conditions applied. The high salt tolerance of amaranth is associated with a low basal stomatal conductance due to a low number of stomata (stomatal density) and degree of stomata aperture (in adaxial surface) of leaves, which contributes to avoid leaf water loss under salt stress in a more efficient way than in quinoa. With respect to Na+ homeostasis, amaranth showed a pattern of Na+ distribution throughout the plant similar to glycophytes, with the highest accumulation found in the roots, followed by the stem and the lowest one detected in the leaves. Contrarily, quinoa exhibited a Na+ includer character with the highest accumulation detected in the shoots. Expression levels of main genes involved in Na+ homeostasis (SOS1, HKT1s, and NHX1) showed different patterns between amaranth and quinoa, with a marked higher basal expression in amaranth roots. These results highlight the important differences in the physiological and molecular responses of amaranth and quinoa when confronted with salinity.

Exosome-Mediated Insulin Delivery for the Potential Treatment of Diabetes Mellitus.

Exosomes are extracellular nanovesicles between 30 and 150 nm that serve as essential messengers for different biological signaling and pathological processes. After their discovery, a wide range of applications have been developed, especially in therapeutic drug delivery. In this context, the aim of this work was to test the efficiency of exosome-mediated human insulin delivery using exosomes extracted from three different cell lines: hepatocellular carcinoma (HepG2); primary dermal fibroblasts (HDFa) and pancreatic ß cells (RIN-m); all are related to the production and/or the ability to sense insulin and to consequently regulate glucose levels in the extracellular medium. The obtained results revealed that the optimal insulin loading efficiency was achieved by a 200 V electroporation, in comparison with incubation at room temperature. Moreover, the maximum in vitro exosome uptake was reached after incubation for 6 h, which slightly decreased 24 h after adding the exosomes. Glucose quantification assays revealed that exosome-mediated incorporation of insulin presented significant differences in HDFa and HepG2 cells, enhancing the transport in HDFa, in comparison with free human insulin effects in the regulation of extracellular glucose levels. No significant differences were found between the treatments in RIN-m cells. Hence, the results suggest that exosomes could potentially become a valuable tool for stable and biocompatible insulin delivery in diabetes mellitus treatment alternatives.

Potential Applications and Functional Roles of Exosomes in Cardiometabolic Disease.

Despite diagnostic and therapeutic advances, cardiometabolic disease remains the leading cause of death worldwide. Extracellular vesicles (EVs), which include exosomes and microvesicles, have gained particular interest because of their role in metabolic homeostasis and cardiovascular physiology. Indeed, EVs are recognized as critical mediators of intercellular communication in the cardiovascular system. Exosomes are naturally occurring nanocarriers that transfer biological information in the setting of metabolic abnormalities and cardiac dysfunction. The study of these EVs can increase our knowledge on the pathophysiological mechanisms of metabolic disorders and their cardiovascular complications. Because of their inherent properties and composition, exosomes have been proposed as diagnostic and prognostic biomarkers and therapeutics for specific targeting and drug delivery. Emerging fields of study explore the use exosomes as tools for gene therapy and as a cell-free alternative for regenerative medicine. Furthermore, innovative biomaterials can incorporate exosomes to enhance tissue regeneration and engineering. In this work, we summarize the most recent knowledge on the role of exosomes in cardiometabolic pathophysiology while highlighting their potential therapeutic applications.

Traditional Tomato Varieties Improve Fruit Quality Without Affecting Fruit Yield Under Moderate Salt Stress.

Identification of tomato varieties able to exhibit higher accumulation of primary and secondary metabolites in their fruits is currently a main objective in tomato breeding. One tool to improve fruit quality is to cultivate the plants under salt stress, although improvement of fruit quality is generally accompanied by productivity losses. However, it is very interesting to implement strategies aiming at enhancing fruit quality of tomato by means of growing plants in moderate salt stress that allows for a sustainable fruit yield. The traditional tomato varieties adapted to the Mediterranean environmental constraints may be very attractive plant materials to achieve this goal, given the wide range of fruit quality traits because of their genetic diversity. Here, agronomic responses and fruit quality traits, including primary and secondary metabolites, were analyzed in fruits of two Mediterranean traditional tomato varieties named "Tomate Pimiento" ("TP") and "Muchamiel Aperado" ("MA") because of the pepper and pear shape of their fruits, using as reference the commercial cultivar "Moneymaker" ("MM"). Plants were grown without salt (control) and with moderate salt stress (50 mM NaCl), which did not affect fruit yield in any variety. "TP" is of great interest because of its high soluble solids content (SSC) in control, which is even higher in salt, whereas "MA" is very attractive because of its high Brix yield index (SSC × fruit yield), used as overall fruit quality measure. Similitude between both traditional varieties were found for primary metabolism, as they significantly increased sucrose contents compared with "MM" in red ripe fruits from plants in control and, especially, salt stress conditions. The most remarkable difference was the high constitutive levels of total amino acids in "TP" fruits, including the three major free amino acids found in tomato fruit, GABA, glutamate, and glutamine, which even increased under salinity. Regarding secondary metabolites, the most interesting change induced by salinity was the increase in α-tocopherol found in red ripe fruits of both "TP" and "MA." These results reveal the interest of traditional varieties as sources of genetic variation in breeding because of their improvement of tomato fruit quality without production losses under moderate salt stress.

The drought-tolerant Solanum pennellii regulates leaf water loss and induces genes involved in amino acid and ethylene/jasmonate metabolism under dehydration.

Breeding for drought-tolerant crops is a pressing issue due to the increasing frequency and duration of droughts caused by climate change. Although important sources of variation for drought tolerance exist in wild relatives, the mechanisms and the key genes controlling tolerance in tomato are little known. The aim of this study is to determine the drought response of the tomato wild relative Solanum pennellii (Sp) compared with the cultivated tomato Solanum lycopersicum (Sl). The paper investigates the physiological and molecular responses in leaves of Sp and Sl plants without stress and moderate drought stress. Significant physiological differences between species were found, with Sp leaves showing greater ability to avoid water loss and oxidative damage. Leaf transcriptomic analysis carried out when leaves did not as yet show visual dehydration symptoms revealed important constitutive expression differences between Sp and Sl species. Genes linked to different physiological and metabolic processes were induced by drought in Sp, especially those involved in N assimilation, GOGAT/GS cycle and GABA-shunt. Up-regulation in Sp of genes linked to JA/ET biosynthesis and signaling pathways was also observed. In sum, genes involved in the amino acid metabolism together with genes linked to ET/JA seem to be key actors in the drought tolerance of the wild tomato species.