Changes in leaf ecophysiological traits and proteome profile provide new insights into variability of salt response in the succulent halophyte Cakile maritima.

Natural variability of stress tolerance in halophytic plants is of significance both ecologically and in view of identifying molecular traits for salt tolerance in plants. Using ecophysiological and proteomic analyses, we address these phenomena in two Tunisian accessions of the oilseed halophyte, Cakile maritima Scop., thriving on arid and semi-arid Mediterranean bioclimatic stages (Djerba and Raoued, respectively), with a special emphasis on the leaves. Changes in biomass, photosynthetic gas exchange and pigment concentrations in C. maritima plants treated with three salinity levels (0, 100 and 300mM NaCl) were monitored for 1month. Comparative two-dimensional gel electrophoresis (2-DE) revealed 94 and 56 proteins of differential abundance in Raoued and Djerba accessions, respectively. These salinity-responsive proteins were mainly related to photosynthesis and oxidative phosphorylation (OXPHOS). Although Djerba accession showed a lower biomass productivity, it showed a slightly higher CO2 assimilation rate than Raoued accession when salt-treated. Photosynthesis impairment in both accessions under salinity was also suggested by the lower abundance of proteins involved in Calvin cycle and electron transfer. A significant increase of protein spots involved in the OXPHOS system was found in Djerba accession, suggesting an increase in mitochondrial respiration for increased ATP production under saline conditions, whereas a lesser pronounced trend was observed for Raoued accession. The latter showed in addition higher abundance of proteins involved in photorespiration. Salt-challenged plants of Djerba also likely developed mechanisms for scavenging ROS in leaves as shown by the increase in superoxide dismutase and thioredoxin, while an opposite trend was found in Raoued.

Recovery aptitude of the halophyte Cakile maritima upon water deficit stress release is sustained by extensive modulation of the leaf proteome.

Among the most intriguing features characterizing extremophile plants is their ability to rapidly recover growth activity upon stress release. Here, we investigated the responses of the halophyte C. maritima to drought and recovery at both physiological and leaf proteome levels. Six week-old plants were either cultivated at 100% or at 25% field capacity. After 12 d of treatment, one lot of dehydrated plants was rewatered to 100% FC for 14 d (stress release). Drought stress impaired shoot hydration, photosynthetic activity and chlorophyll content compared to the control, resulting in severe plant growth restriction. This was concomitant with a marked increase in anthocyanin and proline concentrations. Upon stress release, C. maritima rapidly recovered with respect to all measured parameters. Two-dimensional gel-based proteome analysis of leaves revealed 84 protein spots with significantly changed volumes at the compared conditions: twenty-eight protein spots between normally watered plants and stressed plants but even 70 proteins between stressed and recovered plants. Proteins with higher abundance induced upon rewatering were mostly involved in photosynthesis, glycolytic pathway, TCA cycle, protein biosynthesis, and other metabolic pathways. Overall, C. maritima likely adopts a drought-avoidance strategy, involving efficient mechanisms specifically taking place upon stress release, leading to fast and strong recovery.

Comparative analysis of salt-induced changes in the root proteome of two accessions of the halophyte Cakile maritima.

NaCl stress is a major abiotic stress factor limiting the productivity and the geographical distribution of many plant species. Although halophytes are able to withstand and even to require salt in the rhizosphere, roots are the most sensitive organs to salinity. Here, we investigate the variability of salt tolerance in two Tunisian accessions of the halophyte Cakile maritima (Raoued and Djerba, harvested from the semi-arid and arid Mediterranean bioclimatic stages, respectively) with a special emphasis on the proteomic changes in roots. Seedlings were hydroponically grown for one month under salt-free conditions and subsequently at three salinities (0, 100, and 300 mM NaCl). Physiological parameters (plant growth, water content, Na+, K+ contents) and root protein profiles were analyzed. Plant biomass was higher in Raoued than in Djerba but the latter was impacted to a lesser extent by salinity, notably due to lower sodium accumulation and higher selectivity for K+. 121 and 97 salt-responsive proteins were identified in Djerba and Raoued accessions, respectively. These proteins can be assigned to several different functional categories: protein metabolism, nucleotide metabolism, amino acid metabolism, glutathione metabolism, translation and ribosome biogenesis, carbohydrate and energy metabolism, and reactive oxygen species regulation and detoxification. The comparative proteome analysis revealed that 33 proteins were salt-responsive in both accessions, while 88 and 64 proteins were salt-responsive only in the Djerba or Raoued accessions, respectively. Our results give deeper insights into the plasticity of salt-stress response of C. maritima in its native ecosystems.

High salinity impacts germination of the halophyte Cakile maritima but primes seeds for rapid germination upon stress release.

Seed germination recovery aptitude is an adaptive trait of overriding significance for the successful establishment and dispersal of extremophile plants in their native ecosystems. Cakile maritima is an annual halophyte frequent on Mediterranean coasts, which produces transiently dormant seeds under high salinity, that germinate fast when soil salinity is lowered by rainfall. Here, we report ecophysiological and proteomic data about (1) the effect of high salt (200 mM NaCl) on the early developmental stages (germination and seedling) and (2) the seed germination recovery capacity of this species. Upon salt exposure, seed germination was severely inhibited and delayed and seedling length was restricted. Interestingly, non-germinated seeds remained viable, showing high germination percentage and faster germination than the control seeds after their transfer onto distilled water. The plant phenotypic plasticity during germination was better highlighted by the proteomic data. Salt exposure triggered (1) a marked slower degradation of seed storage reserves and (2) a significant lower abundance of proteins involved in several biological processes (primary metabolism, energy, stress-response, folding and stability). Yet, these proteins showed strong increased abundance early after stress release, thereby sustaining the faster seed storage proteins mobilization under recovery conditions compared to the control. Overall, as part of the plant survival strategy, C. maritima seems to avoid germination and establishment under high salinity. However, this harsh condition may have a priming-like effect, boosting seed germination and vigor under post-stress conditions, sustained by active metabolic machinery.

Chitosan delays ripening and ROS production in guava (Psidium guajava L.) fruit.

Guava is a typically tropical fruit highly perishable with a short shelf-life due to intense metabolic activity after harvested. In attempt to minimize the problems related to the postharvest, we evaluated the physiochemical characteristics and antioxidant system in guava fruits under chitosan coating at concentrations of 1%, 2%, and 3% stored at 25°C during 96h. The chitosan suppressed the respiratory rate, fresh weight loss, firmness and skin color with delay in the degradation of chlorophyll. In the treatment with 2% and 3% of chitosan in the solid soluble content and ascorbic acid were reduced; retarded the loss of titratable acidity during 96h after treatment. These treatment induced significant decreases in the phenylalanine ammonia-lyase activity and significantly increases of peroxidase Activity. Our results suggest that chitosan effectively prolongs the quality attributes in guava fruits after harvesting due to increases in the antioxidant processes, delaying the ripening during room temperature of storage.

Facing the challenge of sustainable bioenergy production: Could halophytes be part of the solution?

Due to steadily growing population and economic transitions in the more populous countries, renewable sources of energy are needed more than ever. Plant biomass as a raw source of bioenergy and biofuel products may meet the demand for sustainable energy; however, such plants typically compete with food crops, which should not be wasted for producing energy and chemicals. Second-generation or advanced biofuels that are based on renewable and non-edible biomass resources are processed to produce cellulosic ethanol, which could be further used for producing energy, but also bio-based chemicals including higher alcohols, organic acids, and bulk chemicals. Halophytes do not compete with conventional crops for arable areas and freshwater resources, since they grow naturally in saline ecosystems, mostly in semi-arid and arid areas. Using halophytes for biofuel production may provide a mid-term economically feasible and environmentally sustainable solution to producing bioenergy, contributing, at the same time, to making saline areas - which have been considered unproductive for a long time - more valuable. This review emphasises on halophyte definition, global distribution, and environmental requirements. It also examines their enzymatic valorization, focusing on salt-tolerant enzymes from halophilic microbial species that may be deployed with greater advantage compared to their conventional mesophilic counterparts for faster degradation of halophyte biomass.

Severity of acne and its impact on quality of life.

Acne is a chronic disease that is especially common among adolescents. It can have a considerable psychological and social impact that is not always correlated with clinical severity. The aim of this paper was to evaluate clinical severity and alteration of quality of life in acne patients, and to investigate a possible correlation between the two. A total of 82 patients with juvenile acne were included in this study. The clinical severity of acne was evaluated using the Echelle de Cotation des Lésions d'Acné (ECLA) scale. The Cardiff Acne Disability Index (CADI) was used to assess acne-related quality of life. Acne was mild to moderate in 61% of patients (ECLA < or = 12). A considerable alteration of quality of life was present in 51% of cases. There was a positive correlation between overall scores on the ECLA and CADI scales (P = .012) before and after treatment. Additionally, CADI score improved after effective treatment of acne. Acne may have an important impact on teenagers' psychological and social life. An objective assessment of this impact seems to be necessary. ECLA and CADI scores appear to be objective and simple instruments that may be used in acne management.

A case of pellagra associated with megaduodenum in a young woman.

Pellagra is a rare condition that has been known for many years to be related to niacin deficiency. Clinically known as the 4 "D" symptoms for dermatitis, diarrhea, dementia, and even death, skin changes remain one of the most important features of this pathology, leading frequently to the diagnosis. Pellagra is mostly seen in poor populations with a deficient diet; still, it is sporadically observed in developed countries, usually in association with digestive disorders. We report a new case of pellagra in a 29-year-old woman in whom the diagnosis of megaduodenum was made. Megaduodenum is a rare condition that can be idiopathic or secondary to visceral myopathy or neuropathy. Parenteral supplementation with niacin has resulted in a quick response of dermatological and psychiatric symptoms. To our knowledge, no case of pellagra due to megaduodenum has been reported in literature.