Effectiveness of Osmoprotectants in Improving Aroma Quality and Yield of Pare Wangi Upland Rice Variety Grown on Two Different Soil Types in East Nusa Tenggara

This study aimed to evaluate the effectiveness of exogenous osmoprotectant application in increasing the stability of aroma quality and grain yield of Pare Wangi on different soil types. A two factors greenhouse experiment was designed according to Split Plot design with three replications. The first factor was soil types of specific and target location. The second factor was application of exogenous osmoprotectants, i.e. without osmoprotectant, 10 mM proline, 20 mM proline, 10 mM sorbitol, 20 mM sorbitol, 10 mM sucrose and 20 mM sucrose. Observed data included soil physical and chemical properties, rice vegetative and reproductive growth and physiological characters, and rice aroma quality. Collected data were subjected to analysis of variance, followed by an Honestly Significant Difference (HSD) post hoc and a simple correlation tests. Results indicated that grain yield per pot was higher on soil from target location than on soil from specific location, but concentration of proline and 2AP, and the aroma scores were in the opposite direction. Besides more effective in increasing grain yield, the osmoprotectants proline and sucrose, each at 10 mM, were also better in maintaining rice aroma quality compared tosorbitol osmoprotectants, and aroma score showed a significantly positive correlation with 2AP concentration

Efficacy of osmoprotectants on prevention and treatment of murine dry eye

Purpose: To evaluate the efficacy of osmoprotectants on prevention and treatment of dry eye in a murine model. Methods: Dry eye was induced in mice by using an intelligently controlled environmental system (ICES). Osmoprotectants betaine, L-carnitine, erythritol, or vehicle (PBS) were topically administered to eyes four times daily following two schedules: schedule 1 (modeling prevention): dosing started at the beginning of housing in ICES and lasted for 21 or 35 days; schedule 2 (modeling treatment): dosing started after ICES-housed mice developed dry eye (day 21), continuing until day 35. Treatment efficacy was evaluated for corneal fluorescein staining; corneal epithelial apoptosis by TUNEL and caspase-3 assays; goblet cell numbers by PAS staining; and expression of inflammatory mediators, TNF-a, IL-17, IL-6, or IL-1b by using RT-PCR on days 0, 14, 21, and/or 35. Results: Compared with vehicle, prophylactic administration of betaine, L-carnitine, or erythritol significantly decreased corneal staining and expression of TNF-a and IL-17 on day 21 (schedule 1). Treatment of mouse dry eye with osmoprotectants significantly reduced corneal staining on day 35 compared with day 21 (schedule 2). Relative to vehicle, L-carnitine treatment of mouse dry eye for 14 days (days 21 to 35) resulted in a significant reduction in corneal staining, number of TUNEL-positive cells, and expression of TNF-a, IL-17, IL-6, or IL- 1b, as well as significantly increased the number of goblet cells. Conclusion: Topical application of betaine, L-carnitine, or erythritol systematically limited progression of environmentally induced dry eye. L-carnitine can also reduce the severity of such dry-eye conditions

Unravelling the adaptation responses to osmotic and temperature stress in Chromohalobacter salexigens, a bacterium with broad salinity tolerance

Chromohalobacter salexigens, a Gammaproteobacterium belonging to the family Halomonadaceae, shows a broad salinity range for growth. Osmoprotection is achieved by the accumulation of compatible solutes either by transport (betaine, choline) or synthesis (mainly ectoine and hydroxyectoine). Ectoines can play additional roles as nutrients and, in the case of hydroxyectoine, in thermotolerance. A supplementary solute, trehalose, not present in cells grown at 37°C, is accumulated at higher temperatures, suggesting its involvement in the response to heat stress. Trehalose is also accumulated at 37°C in ectoine-deficient mutants, indicating that ectoines suppress trehalose synthesis in the wild-type strain. The genes for ectoine (ectABC) and hydroxyectoine (ectD, ectE) production are arranged in three different clusters within the C. salexigens chromosome. In order to cope with changing environment, C. salexigens regulates its cytoplasmic pool of ectoines by a number of mechanisms that we have started to elucidate. This is a highly complex process because (i) hydroxyectoine can be synthesized by other enzymes different to EctD (ii) ectoines can be catabolized to serve as nutrients, (iii) the involvement of several transcriptional regulators (σS, σ32, Fur, EctR) and hence different signal transduction pathways, and (iv) the existence of post-trancriptional control mechanisms. In this review we summarize our present knowledge on the physiology and genetics of the processes allowing C. salexigens to cope with osmotic stress and high temperature, with emphasis on the transcriptional regulation

Novel insights into the Thaumarchaeota in the deepest oceans: their metabolism and potential adaptation mechanisms

Background: Marine Group I (MGI) Thaumarchaeota, which play key roles in the global biogeochemical cycling of nitrogen and carbon (ammonia oxidizers), thrive in the aphotic deep sea with massive populations. Recent studies have revealed that MGI Thaumarchaeota were present in the deepest part of oceans - the hadal zone (depth > 6,000 m, consisting almost entirely of trenches), with the predominant phylotype being distinct from that in the “shallower” deep sea. However, little is known about the metabolism and distribution of these ammonia oxidizers in the hadal water. Results: In this study, metagenomic data were obtained from 0-10,500 m deep seawater samples from the Mariana Trench. The distribution patterns of Thaumarchaeota derived from metagenomics and 16S rRNA gene sequencing were in line with that reported in previous studies: abundance of Thaumarchaeota peaked in bathypelagic zone (depth 1,000 – 4,000 m) and the predominant clade shifted in the hadal zone. Several metagenome-assembled thaumarchaeotal genomes were recovered, including a near-complete one representing the dominant hadal phylotype of MGI. Using comparative genomics we predict that unexpected genes involved in bioenergetics, including two distinct ATP synthase genes (predicted to be coupled with H+ and Na+ respectively), and genes horizontally transferred from other extremophiles, such as those encoding putative di-myo-inositol-phosphate (DIP) synthases, might significantly contribute to the success of this hadal clade under the extreme condition. We also found that hadal MGI have the genetic potential to import a far higher range of organic compounds than their shallower water counterparts. Despite this trait, hadal MDI ammonia oxidation and carbon fixation genes are highly transcribed providing evidence they are likely autotrophic, contributing to the primary production in the aphotic deep sea. Conclusions: Our study reveals potentially novel adaptation mechanisms of deep-sea thaumarchaeotal clades and suggests key functions of deep-sea Thaumarchaeota in carbon and nitrogen cycling

Germination of primed seed under NaCl stress in wheat.

Copyright © 2012 Michael P. Fuller et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Soil salinity affects a large and increasing amount of arable land worldwide, and genetic and agronomic solutions to increasing salt tolerance are urgently needed. Experiments were conducted to improve wheat seed performance under salinity stress conditions after priming. An experiment was conducted using a completely randomized design of four replications for germination indices in wheat (Triticum aestivum L. cv. Caxton). Normal and primed seed with PEG6000 at −1MPa and five concentrations of NaCl (0, 50, 100, 150, and 200mM) were tested. Results indicate that priming seed significantly (P < 0.05) increased germination percentage at first count and final count, coefficient of velocity of germination, germination rate index, and mean germination time, while increasing of NaCl concentration significantly reduced it. Priming seed improved germination attributes at all NaCl concentration levels. The priming appeared to be able to overcome the effect of salt stress at 50 to 100mMand reduce the effect of NaCl at higher concentrations up to 200 mM. The primed seed gave both faster germination and led to higher germination when under salt stress. We conclude that using priming techniques can effectively enhance the germination seed under saline condition

Quantitative RNA-seq Analysis Unveils Osmotic and Thermal Adaptation Mechanisms Relevant for Ectoine Production in Chromohalobacter salexigens

Quantitative RNA sequencing (RNA-seq) and the complementary phenotypic assays were implemented to investigate the transcriptional responses of Chromohalobacter salexigens to osmotic and heat stress. These conditions trigger the synthesis of ectoine and hydroxyectoine, two compatible solutes of biotechnological interest. Our findings revealed that both stresses make a significant impact on C. salexigens global physiology. Apart from compatible solute metabolism, the most relevant adaptation mechanisms were related to “oxidative- and protein-folding- stress responses,” “modulation of respiratory chain and related components,” and “ion homeostasis.” A general salt-dependent induction of genes related to the metabolism of ectoines, as well as repression of ectoine degradation genes by temperature, was observed. Different oxidative stress response mechanisms, secondary or primary, were induced at low and high salinity, respectively, and repressed by temperature. A higher sensitivity to H2O2 was observed at high salinity, regardless of temperature. Low salinity induced genes involved in “protein-folding-stress response,” suggesting disturbance of protein homeostasis. Transcriptional shift of genes encoding three types of respiratory NADH dehydrogenases, ATP synthase, quinone pool, Na+/H+ antiporters, and sodium-solute symporters, was observed depending on salinity and temperature, suggesting modulation of the components of the respiratory chain and additional systems involved in the generation of H+ and/or Na+ gradients. Remarkably, the Na+ intracellular content remained constant regardless of salinity and temperature. Disturbance of Na+- and H+-gradients with specific ionophores suggested that both gradients influence ectoine production, but with differences depending on the solute, salinity, and temperature conditions. Flagellum genes were strongly induced by salinity, and further induced by temperature. However, salt-induced cell motility was reduced at high temperature, possibly caused by an alteration of Na+ permeability by temperature, as dependence of motility on Na+-gradient was observed. The transcriptional induction of genes related to the synthesis and transport of siderophores correlated with a higher siderophore production and intracellular iron content only at low salinity. An excess of iron increased hydroxyectoine accumulation by 20% at high salinity. Conversely, it reduced the intracellular content of ectoines by 50% at high salinity plus high temperature. These findings support the relevance of iron homeostasis for osmoadaptation, thermoadaptation and accumulation of ectoines, in C. salexigens.España Ministerio de Economía y Competitividad BIO2015-63949-RJunta de Andalucía P11-CVI-729

A pivotal role for starch in the reconfiguration of 14C-partitioning and allocation in Arabidopsis thaliana under short-term abiotic stress.

Plant carbon status is optimized for normal growth but is affected by abiotic stress. Here, we used 14C-labeling to provide the first holistic picture of carbon use changes during short-term osmotic, salinity, and cold stress in Arabidopsis thaliana. This could inform on the early mechanisms plants use to survive adverse environment, which is important for efficient agricultural production. We found that carbon allocation from source to sinks, and partitioning into major metabolite pools in the source leaf, sink leaves and roots showed both conserved and divergent responses to the stresses examined. Carbohydrates changed under all abiotic stresses applied; plants re-partitioned 14C to maintain sugar levels under stress, primarily by reducing 14C into the storage compounds in the source leaf, and decreasing 14C into the pools used for growth processes in the roots. Salinity and cold increased 14C-flux into protein, but as the stress progressed, protein degradation increased to produce amino acids, presumably for osmoprotection. Our work also emphasized that stress regulated the carbon channeled into starch, and its metabolic turnover. These stress-induced changes in starch metabolism and sugar export in the source were partly accompanied by transcriptional alteration in the T6P/SnRK1 regulatory pathway that are normally activated by carbon starvation