A novel function of the tomato CALCINEURIN-B LIKE 10 gene as a root-located negative regulator of salt stress.

Climate change exacerbates abiotic stresses like salinization, negatively impacting crop yield, so development of strategies, like using salt-tolerant rootstocks, is crucial. The CALCINEURIN B-LIKE 10 (SlCBL10) gene has been previously identified as a positive regulator of salt tolerance in the tomato shoot. Here, we report a different function of SlCBL10 in tomato shoot and root, as disruption of SlCBL10 only induced salt sensitivity when it was used in the scion but not in the rootstock.

Salt-tolerant alternative crops as sources of quality food to mitigate the negative impact of salinity on agricultural production.

An increase of abiotic stress tolerance and nutritive value of foods is currently a priority because of climate change and rising world population. Among abiotic stresses, salt stress is one of the main problems in agriculture. Mounting urbanization and industrialization, and increasing global food demand, are pressing farmers to make use of marginal lands affected by salinity and low-quality saline water.

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.

The Ca Sensor Calcineurin B-Like Protein 10 in Plants: Emerging New Crucial Roles for Plant Abiotic Stress Tolerance.

Ca is a second messenger that mediates plant responses to abiotic stress; Ca signals need to be decoded by Ca sensors that translate the signal into physiological, metabolic, and molecular responses. Recent research regarding the Ca sensor CALCINEURIN B-LIKE PROTEIN 10 (CBL10) has resulted in important advances in understanding the function of this signaling component during abiotic stress tolerance. Under saline conditions, CBL10 function was initially understood to be linked to regulation of Na homeostasis, protecting plant shoots from salt stress.

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 Salt Sensitivity Induced by Disruption of Cell Wall-Associated Kinase 1 () Tomato Gene Is Linked to Altered Osmotic and Metabolic Homeostasis.

Tomato cell wall-associated kinase 1 () has only been studied in biotic stress response and hence its function in abiotic stress remains unknown. In a screening under salinity of an insertional mutant collection of tomato ( L.), a mutant exhibiting lower degree of leaf chlorosis than wild type (WT) together with reduced leaf Na accumulation was selected.

The res (restored cell structure by salinity) tomato mutant reveals the role of the DEAD-box RNA helicase SlDEAD39 in plant development and salt response.

Increasing evidences highlight the importance of DEAD-box RNA helicases in plant development and stress responses. In a previous study, we characterized the tomato res mutant (restored cell structure by salinity), showing chlorosis and development alterations that reverted under salt-stress conditions. Map-based cloning demonstrates that RES gene encodes SlDEAD39, a chloroplast-targeted DEAD-box RNA helicase.

Recovering Tomato Landraces to Simultaneously Improve Fruit Yield and Nutritional Quality Against Salt Stress.

Salt stress generally induces important negative effects on tomato () productivity but it may also cause a positive effect improving fruit quality, one of the greatest challenges in nowadays agriculture. Because of the genetic erosion of this horticultural species, the recovery of locally adapted landraces could play a very important role in avoiding, at least partially, production losses and simultaneously improving fruit quality. Two tomato landraces endemic of the Spanish Southeast area, characterized by the harsh climatic conditions of the Mediterranean basin, have been selected: Negro Yeste (NY) characterized by its dark-red colored fruits and Verdal (V), which fruits did not achieve the characteristic red color at ripening.

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 Ca signalling, transcription factors and others related to stress responses.

Developmental role of the tomato Mediator complex subunit MED18 in pollen ontogeny.

Pollen development is a crucial step in higher plants, which not only makes possible plant fertilization and seed formation, but also determines fruit quality and yield in crop species. Here, we reported a tomato T-DNA mutant, pollen deficient1 (pod1), characterized by an abnormal anther development and the lack of viable pollen formation, which led to the production of parthenocarpic fruits. Genomic analyses and the characterization of silencing lines proved that pod1 mutant phenotype relies on the tomato SlMED18 gene encoding the subunit 18 of Mediator multi-protein complex involved in RNA polymerase II transcription machinery.

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 SlCBL10 Calcineurin B-Like Protein Ensures Plant Growth under Salt Stress by Regulating Na and Ca Homeostasis.

Characterization of a new tomato () T-DNA mutant allowed for the isolation of the () gene whose lack of function was responsible for the severe alterations observed in the shoot apex and reproductive organs under salinity conditions. Physiological studies proved that gene is required to maintain a proper low Na/Ca ratio in growing tissues allowing tomato growth under salt stress. Expression analysis of the main responsible genes for Na compartmentalization (i.

The phenotype alterations showed by the res tomato mutant disappear when the plants are grown under semi-arid conditions: Is the res mutant tolerant to multiple stresses?

The res (restored cell structure by salinity) mutant, recently identified as the first tomato mutant accumulating jasmonate (JA) without stress, exhibited important morphological alterations when plants were grown under control conditions but these disappeared under salt stress. Since the defense responses against stresses are activated in the res mutant as a consequence of the increased expression of genes from the JA biosynthetic and signaling pathways, the mutant may display a tolerance response not only to salt stress but also to multiple stresses. Here, we show that when res mutant plants are grown under the summer natural conditions of the Mediterranean area, with high temperatures and low relative humidity, the characteristic leaf chlorosis exhibited by the mutant disappears and leaves become dark green over time, with a similar aspect to WT leaves.

The tomato mutant ars1 (altered response to salt stress 1) identifies an R1-type MYB transcription factor involved in stomatal closure under salt acclimation.

A screening under salt stress conditions of a T-DNA mutant collection of tomato (Solanum lycopersicum L.) led to the identification of the altered response to salt stress 1 (ars1) mutant, which showed a salt-sensitive phenotype. Genetic analysis of the ars1 mutation revealed that a single T-DNA insertion in the ARS1 gene was responsible of the mutant phenotype.

The tomato res mutant which accumulates JA in roots in non-stressed conditions restores cell structure alterations under salinity.

Jasmonic acid (JA) regulates a wide spectrum of plant biological processes, from plant development to stress defense responses. The role of JA in plant response to salt stress is scarcely known, and even less known is the specific response in root, the main plant organ responsible for ionic uptake and transport to the shoot. Here we report the characterization of the first tomato (Solanum lycopersicum) mutant, named res (restored cell structure by salinity), that accumulates JA in roots prior to exposure to stress.

Heterologous expression of the yeast HAL5 gene in tomato enhances salt tolerance by reducing shoot Na+ accumulation in the long term.

For salt tolerance to be achieved in the long-term plants must regulate Na(+)/K(+) homeostasis over time. In this study, we show that the salt tolerance induced by overexpression of the yeast HAL5 gene in tomato (Solanum lycopersicum) was related to a lower leaf Na(+) accumulation in the long term, by reducing Na(+) transport from root to shoot over time regardless of the severity of salt stress. Furthermore, maintaining Na(+)/K(+) homeostasis over time was associated with changes in the transcript levels of the Na(+) and K(+) transporters such as SlHKT1;2 and SlHAK5.

Proteomic analysis of chloroplast-to-chromoplast transition in tomato reveals metabolic shifts coupled with disrupted thylakoid biogenesis machinery and elevated energy-production components.

A comparative proteomic approach was performed to identify differentially expressed proteins in plastids at three stages of tomato (Solanum lycopersicum) fruit ripening (mature-green, breaker, red). Stringent curation and processing of the data from three independent replicates identified 1,932 proteins among which 1,529 were quantified by spectral counting. The quantification procedures have been subsequently validated by immunoblot analysis of six proteins representative of distinct metabolic or regulatory pathways.

Understanding the mechanisms of chilling injury in bell pepper fruits using the proteomic approach.

In order to advance in the understanding of CI in pepper fruits, the cell ultrastructure alterations induced by CI and the physiological and metabolic changes have been studied along with the proteomic study. When stored at low temperatures bell pepper (Capsicum annuum) fruits exhibited visual CI symptoms and important alterations within the cell ultrastructure, since peroxisomes and starch grains were not detected and the structure of the chloroplast was seriously damaged in chilled tissues. Physiological and metabolic disorders were also observed in chilled fruits, such as higher ethylene production, increased MDA content, changes in sugar and organic acids and enzymatic activities.

Proteome changes in tomato fruits prior to visible symptoms of chilling injury are linked to defensive mechanisms, uncoupling of photosynthetic processes and protein degradation machinery.

A comparative proteomic analysis between tomato fruits stored at chilling and non-chilling temperatures was carried out just before the appearance of visible symptoms of chilling injury. At this stage of the stress period it was possible to discriminate between proteins involved in symptoms and proteins implicated in response. To investigate the changes in the tomato fruit proteome under this specific stressful condition, two-dimensional differential in-gel electrophoresis coupled with spot identification by mass spectrometry was applied.

Chloroplast to chromoplast transition in tomato fruit: spectral confocal microscopy analyses of carotenoids and chlorophylls in isolated plastids and time-lapse recording on intact live tissue.

Background And Aims: There are several studies suggesting that tomato (Solanum lycopersicum) chromoplasts arise from chloroplasts, but there is still no report showing the fluorescence of both chlorophylls and carotenoids in an intermediate plastid, and no video showing this transition phase.

Methods: Pigment fluorescence within individual plastids, isolated from tomato fruit using sucrose gradients, was observed at different ripening stages, and an in situ real-time recording of pigment fluorescence was performed on live tomato fruit slices.

Key Results: At the mature green and red stages, homogenous fractions of chloroplasts and chromoplasts were obtained, respectively.

Chromoplast differentiation: current status and perspectives.

Chromoplasts are carotenoid-accumulating plastids conferring color to many flowers and fruits as well as to some tubers and roots. Chromoplast differentiation proceeds from preexisting plastids, most often chloroplasts. One of the most prominent changes is remodeling of the internal membrane system associated with the formation of carotenoid-accumulating structures.

Characteristics of the tomato chromoplast revealed by proteomic analysis.

Chromoplasts are non-photosynthetic specialized plastids that are important in ripening tomato fruit (Solanum lycopersicum) since, among other functions, they are the site of accumulation of coloured compounds. Analysis of the proteome of red fruit chromoplasts revealed the presence of 988 proteins corresponding to 802 Arabidopsis unigenes, among which 209 had not been listed so far in plastidial databanks. These data revealed several features of the chromoplast.

1-Methylcyclopropene affects the antioxidant system of apricots (Prunus armeniaca L. cv. Búlida) during storage at low temperature.

Background: Apricots (Prunus armeniaca cv. Búlida) were treated with 1 μL L⁻¹ [corrected] 1-methylcyclopropene (1-MCP) immediately after harvest and stored in air at 2 degrees C for 21 days. Antioxidant levels (ascorbic acid and carotenoids), enzymatic antioxidant activities (superoxide dismutase (SOD) and unspecific peroxidase (POX)) and total antioxidant capacity (trolox equivalent antioxidant capacity (TEAC)) were determined.

Six edible wild fruits as potential antioxidant additives or nutritional supplements.

Total antioxidant activity of six non-cultivated but traditionally collected fruits from the south of Europe was assessed by measuring their ability to reduce the hydroxyl radical (OH) and hydrogen peroxide (H(2)O(2)), and their Trolox equivalent antioxidant capacity (TEAC). This antioxidant activity was compared with that shown by the synthetic antioxidants BHA (E-320), BHT (E-321) and propyl gallate (E-310). Total phenolics, ascorbic acid and the carotenoid content of the fruits were also analyzed.

Oil quality and sensory evaluation of almond (Prunus amygdalus) stored after electron beam processing.

The changes in the lipid fraction and the deterioration of its quality were studied in almonds (Prunus amygdalus) of the variety Guara after treatment with accelerated electrons at doses of 3, 7, and 10 kGy, during a storage period of 5 months. In almond oil, the most significant difference from the nutritional point of view was seen in the fatty acid linolenic (18:3), which shows at 3 kGy a maintenance of the initial content during the whole storage period, whereas, at 7 and 10 kGy, the content in 18:3 disappears from the first moment. The quality indices of the oil (K(232), K(270)) decreased at all doses and remained stable during the time of storage.