Glycinebetaine Biosynthesis in Response to Osmotic Stress Depends on Jasmonate Signaling in Watermelon Suspension Cells

Glycine betaine and plant abiotic stresses: Unravelling physiological and molecular responses

Plants are constantly subjected to various abiotic stresses (drought, salinity, heavy metals and low temperature) throughout their life cycle, which significantly hinder their growth and productivity. Key abiotic stresses include drought, salinity, heavy metals, and extreme temperatures. In response, plants modulate glycine betaine (GB) levels, a vital compatible solute that influences growth and stress tolerance by interacting with phytohormones and cellular signaling pathways. Not all species can synthesize endogenous GB; however, some non-GB accumulating plants have been genetically modified to enhance GB production through the overexpression of synthesis genes such as choline oxidase, choline monooxygenase, and betaine aldehyde dehydrogenase. Exogenous GB treatment can mitigate stress effects by improving nutritional balance, reducing reactive oxygen species (ROS), minimizing membrane damage, and alleviating photoinhibition. Nonetheless, the specificity of GB application, transport, and accumulation across species, as well as its interaction with phytohormones in stress alleviation, remains uncertain. This review focuses on GB's role as an antioxidant, osmo-regulator, and nitrogen source, evaluating the physiological, biochemical, and molecular mechanisms by which GB mitigates abiotic stresses, aiming to develop GB-based strategies for enhancing plant stress resilience.

Identification of the maize drought-resistant gene Zinc-finger Inflorescence Meristem 23 through high-resolution temporal transcriptome analysis

Drought is a major abiotic stress that significantly limits maize productivity. However, previous transcriptomic studies with limited time-point sampling have hindered the construction of robust co-expression networks, making it challenging to identify reliable hub genes involved in drought tolerance. To overcome this limitation, we generated a high-temporal-resolution transcriptome dataset spanning 108 time points from maize seedlings subjected to two consecutive rounds of drought and re-watering treatments. A total of 8477 drought-responsive genes (DRGs) were identified by comparing drought-stressed and well-watered controls. Using weighted gene co-expression network analysis (WGCNA), we constructed 17 co-expression modules, of which 8 were strongly associated with drought stress responses and collectively contained 353 hub genes. Among them, we validated the drought resistance functions of ZmCPK35, a known drought-responsive gene, and Zinc-finger Inflorescence Meristem 23 (ZmZIM23), a newly identified drought-regulatory gene, within the M10 module. Functional analysis revealed that ZmZIM23 enhances drought tolerance by improving water-use efficiency, reducing transpiration rates, and promoting biomass accumulation. Furthermore, yeast one-hybrid (Y1H) and dual-luciferase (LUC) assays demonstrated that ZmWRKY40, another M10 module member, transcriptionally regulates both ZmZIM23 and ZmCPK35. By integrating high-resolution transcriptomic data with co-expression network analyses, this study unveils key drought-responsive regulatory networks in maize and identifies novel candidate genes for improving drought tolerance. These findings provide valuable insights into the genetic foundation of drought adaptation and offer potential targets for the development of drought-resistant maize cultivars.

A GDSL motif-containing lipase modulates Sclerotinia sclerotiorum resistance in Brassica napus

Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum (Lib.) De Bary is a devastating disease infecting hundreds of plant species. It also restricts the yield, quality, and safe production of rapeseed (Brassica napus) worldwide. However, the lack of resistance sources and genes to S. sclerotiorum has greatly restricted rapeseed SSR-resistance breeding. In this study, a previously identified GDSL motif-containing lipase gene, B. napus GDSL LIPASE-LIKE 1 (BnaC07.GLIP1), encoding a protein localized to the intercellular space, was characterized as functioning in plant immunity to S. sclerotiorum. The BnaC07.GLIP1 promoter is S. sclerotiorum-inducible and the expression of BnaC07.GLIP1 is substantially enhanced after S. sclerotiorum infection. Arabidopsis (Arabidopsis thaliana) heterologously expressing and rapeseed lines overexpressing BnaC07.GLIP1 showed enhanced resistance to S. sclerotiorum, whereas RNAi suppression and CRISPR/Cas9 knockout B. napus lines were hyper-susceptible to S. sclerotiorum. Moreover, BnaC07.GLIP1 affected the lipid composition and induced the production of phospholipid molecules, such as phosphatidylethanolamine, phosphatidylcholine, and phosphatidic acid, which were correlated with decreased levels of reactive oxygen species (ROS) and enhanced expression of defense-related genes. A B. napus bZIP44 transcription factor specifically binds the CGTCA motif of the BnaC07.GLIP1 promoter to positively regulate its expression. BnbZIP44 responded to S. sclerotiorum infection, and its heterologous expression inhibited ROS accumulation, thereby enhancing S. sclerotiorum resistance in Arabidopsis. Thus, BnaC07.GLIP1 functions downstream of BnbZIP44 and is involved in S. sclerotiorum resistance by modulating the production of phospholipid molecules and ROS homeostasis in B. napus, providing insights into the potential roles and functional mechanisms of BnaC07.GLIP1 in plant immunity and for improving rapeseed SSR disease-resistance breeding.

Toxicity of antimony to plants: Effects on metabolism of N and S in a rice plant

Excess antimony (Sb) has been shown to damage plant growth. Rice plants readily absorb a large amount of Sb after a long period of flooding, yet the mechanisms underlying Sb toxicity in plants have not been solved. This study was conducted to explore the effects of Sb on the uptake of N and S, and monitor the concentrations of reduced glutathione (GSH) and enzymes associated with these processes. In addition, we analyzed differentially expressed metabolites (DEMs) correlated with amino acids (AAs) and oligopeptides, specifically DEMs containing sulfur (S), GSH and indole-3-acetic acid (IAA). The results showed that antimonite [Sb(III)] inhibited shoot growth whereas antimonate [Sb(V)] stimulated shoot growth. Interestingly, Sb(III)5/10 enhanced shoot concentrations of total nitrogen (N), NH4+-N [only at Sb(III)10] and S; but reduced the shoot concentrations of NO3-N and soluble protein. Sb(III)5/10 addition significantly increased oxidized glutathione (GSSG) concentration and activities of glutathione peroxidase (GSH-Px) and glutathione S-transferase (GST) but non-significantly affected concentration of reduced glutathione (GSH) and activities of γ-glutamylcysteine synthetase (GCL) and glutathione reductase (GR), suggesting Sb(III) restricted GSH recycling. Addition of Sb (1) increased the abundance of DEMs associated with lignins, Ca uptake, toxicity/detoxification, and branched chain AAs; (2) decreased the abundance of AAs inclcuding isoleucine (Ile), leucine (Leu), tryptophan (Trp), tyrosine (Tyr) and histidine (His); (3) increased the abundance of arginine (Arg), putrescine (Put) and spermidine (Spd); and (4) affected methylation and acetylation of many AAs, especially acetylation.

An Integrated Framework for Drought Stress in Plants

With global warming, drought stress is becoming increasingly severe, causing serious impacts on crop yield and quality. In order to survive under adverse conditions such as drought stress, plants have evolved a certain mechanism to cope. The tolerance to drought stress is mainly improved through the synergistic effect of regulatory pathways, such as transcription factors, phytohormone, stomatal movement, osmotic substances, sRNA, and antioxidant systems. This study summarizes the research progress on plant drought resistance, in order to provide a reference for improving plant drought resistance and cultivating drought-resistant varieties through genetic engineering technology.

Regulation of Proline Accumulation and Protein Secretion in Sorghum under Combined Osmotic and Heat Stress

Plants reprogramme their proteome to alter cellular metabolism for effective stress adaptation. Intracellular proteomic responses have been extensively studied, and the extracellular matrix stands as a key hub where peptide signals are generated/processed to trigger critical adaptive signal transduction cascades inaugurated at the cell surface. Therefore, it is important to study the plant extracellular proteome to understand its role in plant development and stress response. This study examined changes in the soluble extracellular sub-proteome of sorghum cell cultures exposed to a combination of sorbitol-induced osmotic stress and heat at 40 °C. The combined stress significantly reduced metabolic activity and altered protein secretion. While cells treated with osmotic stress alone had elevated proline content, the osmoprotectant in the combined treatment remained unchanged, confirming that sorghum cells exposed to combined stress utilise adaptive processes distinct from those invoked by the single stresses applied separately. Reactive oxygen species (ROS)-metabolising proteins and proteases dominated differentially expressed proteins identified in cells subjected to combined stress. ROS-generating peroxidases were suppressed, while ROS-degrading proteins were upregulated for protection from oxidative damage. Overall, our study provides protein candidates that could be used to develop crops better suited for an increasingly hot and dry climate.

Salt and drought stress-mitigating approaches in sugar beet (Beta vulgaris L.) to improve its performance and yield

MAIN CONCLUSION

Although sugar beet is a salt- and drought-tolerant crop, high salinity, and water deprivation significantly reduce its yield and growth. Several reports have demonstrated stress tolerance enhancement through stress-mitigating strategies including the exogenous application of osmolytes or metabolites, nanoparticles, seed treatments, breeding salt/drought-tolerant varieties. These approaches would assist in achieving sustainable yields despite global climatic changes. Sugar beet (Beta vulgaris L.) is an economically vital crop for ~ 30% of world sugar production. They also provide essential raw materials for bioethanol, animal fodder, pulp, pectin, and functional food-related industries. Due to fewer irrigation water requirements and shorter regeneration time than sugarcane, beet cultivation is spreading to subtropical climates from temperate climates. However, beet varieties from different geographical locations display different stress tolerance levels. Although sugar beet can endure moderate exposure to various abiotic stresses, including high salinity and drought, prolonged exposure to salt and drought stress causes a significant decrease in crop yield and production. Hence, plant biologists and agronomists have devised several strategies to mitigate the stress-induced damage to sugar beet cultivation. Recently, several studies substantiated that the exogenous application of osmolytes or metabolite substances can help plants overcome injuries induced by salt or drought stress. Furthermore, these compounds likely elicit different physio-biochemical impacts, including improving nutrient/ionic homeostasis, photosynthetic efficiency, strengthening defense response, and water status improvement under various abiotic stress conditions. In the current review, we compiled different stress-mitigating agricultural strategies, prospects, and future experiments that can secure sustainable yields for sugar beets despite high saline or drought conditions.

In vitro and in vivo screening for the identification of salt-tolerant sugarcane (Saccharum officinarum L.) clones: molecular, biochemical, and physiological responses to salt stress

Sugarcane is a glycophyte whose growth and yield can be negatively affected by salt stress. As the arable lands with potential saline soils expand annually, the increase of salt-tolerance in sugarcane cultivars is highly desired. We, herein, employed in vitro and in vivo conditions in order to screen sugarcane plants for salt tolerance at the cellular and at the whole plant levels. Calli of sugarcane cv. Khon Kaen 3 (KK3) were selected after culturing in selective media containing various NaCl concentrations, and regenerated plants were then reselected after culturing in selective media containing higher NaCl concentrations. The surviving plants were finally selected after an exposure to 254 mM NaCl under greenhouse conditions. A total of 11 sugarcane plants survived the selection process. Four plants that exhibited tolerance to the four different salt concentrations applied during the aforementioned screening process were then selected for the undertaking of further molecular, biochemical, and physiological studies. The construction of a dendrogram has revealed that the most salt-tolerant plant was characterized by the lowest genetic similarity to the original cultivar. The relative expression levels of six genes (i.e., SoDREB, SoNHX1, SoSOS1, SoHKT, SoBADH, and SoMIPS) were found to be significantly higher in the salt-tolerance clones than those measured in the original plant. The measured proline levels, the glycine betaine content, the relative water content, the SPAD unit, the contents of chlorophyll a and b, as well as the K⁺/Na⁺ ratios of the salt-tolerant clones were also found to be significantly higher than those of the original plant.When the salt-tolerant clones were grown in a low saline soil, they exhibited a higher Brix percentage than that of the original cultivar.

Molecular Characterization of Indigenous Rhizobia from Kenyan Soils Nodulating with Common Beans

Kenya is the seventh most prominent producer of common beans globally and the second leading producer in East Africa. However, the annual national productivity is low due to insufficient quantities of vital nutrients and nitrogen in the soils. Rhizobia are symbiotic bacteria that fix nitrogen through their interaction with leguminous plants. Nevertheless, inoculating beans with commercial rhizobia inoculants results in sparse nodulation and low nitrogen supply to the host plants because these strains are poorly adapted to the local soils. Several studies describe native rhizobia with much better symbiotic capabilities than commercial strains, but only a few have conducted field studies. This study aimed to test the competence of new rhizobia strains that we isolated from Western Kenya soils and for which the symbiotic efficiency was successfully determined in greenhouse experiments. Furthermore, we present and analyze the whole-genome sequence for a promising candidate for agricultural application, which has high nitrogen fixation features and promotes common bean yields in field studies. Plants inoculated with the rhizobial isolate S3 or with a consortium of local isolates (COMB), including S3, produced a significantly higher number of seeds and seed dry weight when compared to uninoculated control plants at two study sites. The performance of plants inoculated with commercial isolate CIAT899 was not significantly different from uninoculated plants (p > 0.05), indicating tight competition from native rhizobia for nodule occupancy. Pangenome analysis and the overall genome-related indices showed that S3 is a member of R. phaseoli. However, synteny analysis revealed significant differences in the gene order, orientation, and copy numbers between S3 and the reference R. phaseoli. Isolate S3 is phylogenomically similar to R. phaseoli. However, it has undergone significant genome rearrangements (global mutagenesis) to adapt to harsh conditions in Kenyan soils. Its high nitrogen fixation ability shows optimal adaptation to Kenyan soils, and the strain can potentially replace nitrogenous fertilizer application. We recommend that extensive fieldwork in other parts of the country over a period of five years be performed on S3 to check on how the yield changes with varying whether conditions.

The identification of the new species Nitratireductor thuwali sp. nov. reveals the untapped diversity of hydrocarbon-degrading culturable bacteria from the arid mangrove sediments of the Red Sea

Introduction

The geological isolation, lack of freshwater inputs and specific internal water circulations make the Red Sea one of the most extreme-and unique-oceans on the planet. Its high temperature, salinity and oligotrophy, along with the consistent input of hydrocarbons due to its geology (e.g., deep-sea vents) and high oil tankers traffic, create the conditions that can drive and influence the assembly of unique marine (micro)biomes that evolved to cope with these multiple stressors. We hypothesize that mangrove sediments, as a model-specific marine environment of the Red Sea, act as microbial hotspots/reservoirs of such diversity not yet explored and described.

Methods

To test our hypothesis, we combined oligotrophic media to mimic the Red Sea conditions and hydrocarbons as C-source (i.e., crude oil) with long incubation time to allow the cultivation of slow-growing environmentally (rare or uncommon) relevant bacteria.

Results and discussion

This approach reveals the vast diversity of taxonomically novel microbial hydrocarbon degraders within a collection of a few hundred isolates. Among these isolates, we characterized a novel species, Nitratireductor thuwali sp. nov., namely, Nit1536^T. It is an aerobic, heterotrophic, Gram-stain-negative bacterium with optimum growth at 37°C, 8 pH and 4% NaCl, whose genome and physiological analysis confirmed the adaptation to extreme and oligotrophic conditions of the Red Sea mangrove sediments. For instance, Nit1536^T metabolizes different carbon substrates, including straight-chain alkanes and organic acids, and synthesizes compatible solutes to survive in salty mangrove sediments. Our results showed that the Red Sea represent a source of yet unknown novel hydrocarbon degraders adapted to extreme marine conditions, and their discovery and characterization deserve further effort to unlock their biotechnological potential.

Mild shading promotes sesquiterpenoid synthesis and accumulation in Atractylodes lancea by regulating photosynthesis and phytohormones

Atractylodes lancea rhizome (AR) has high medicinal and economic value. A previous study has reported that the accumulation of sesquiterpenoids in AR has obvious advantages under bamboo canopy. A concrete shade value to promote the cultivation of high-quality AR has not been established. In this study, 80% shading was screened at six different light intensities (100%, 80%, 60%, 40%, 20%, 7%), and the mechanism was explored in terms of photosynthetic efficiency and phytohormones levels. The results indicated that the total sesquiterpenoid content of 80% mild shading increased by 58%, 52%, and 35%, respectively, compared to 100% strong light in seedling, expansion, and harvest stages and increased by 144%, 178%, and 94%, respectively, compared with 7% low light. The sesquiterpenoids hinesol and β-eudesmol contributed approximately 70% to the differential contribution ratio between mild shading and strong light (100%) or between mild shading and low light (7%). Furthermore, HMGR, DXR, and FPPS genes, which regulate sesquiterpenoid synthesis, were significantly upregulated in 80% mild shading. Transpiration rate; the intercellular CO₂ concentration; net photosynthetic rate; and levels of jasmonic acid, abscisic acid, and gibberellin were strongly correlated (r > 0.85) with sesquiterpenoid accumulation. Cis-acting elements responding to light and phytohormones were present within the promoter regions of HMGR, DXR, and FPPS. Therefore, 80% shading promotes the synthesis and accumulation of sesquiterpenoids in AR by regulating photosynthetic efficiency and phytohormone production, thereby promoting transcriptional expression.

Plant hormone signals regulate trehalose accumulation against osmotic stress in watermelon cells

Trehalose, one of the most chemically stable sugars, can effectively improve the tolerance of various plants against abiotic stress by protecting and stabilizing protein and cell membranes. However, the signaling pathway in trehalose biosynthesis triggered by abiotic stresses is still unclear. In the study, it can be shown that exogenous trehalose can alleviate the inhibitory effect of osmotic stress on cell growth, suppress extracellular alkalization, ROS burst, and maintain the integrity of the microtubular cytoskeleton. Trehalose-6-phosphate synthase (TPS) is the key limiting enzyme for trehalose synthesis and is encoded by 7 ClTPS genes, located in 7 different chromosomes of the watermelon genome. Expression analysis by qRT-PCR indicated that osmotic stress could upregulate the expression of all the family members of ClTPS and promote the accumulation of trehalose in watermelon cells accordingly. Exogenous methyl jasmonate (MeJA), ethephon (ETH), abscisic acid (ABA), or salicylic acid (SA) induced trehalose accumulation, with MeJA being the most effective treatment. When fluridone (FL), an ABA biosynthesis inhibitor, was pre-perfused into the cells before osmotic stress, trehalose accumulation and packed cell volume were suppressed significantly, whereas inhibition of ethylene biosynthesis could even restore cell growth. Moreover, inhibition of trehalose hydrolysis could also increase the tolerance against osmotic stress. This study shows that trehalose biosynthesis is phytohormone-dependent and the hydrolysis of trehalose is involved in osmotic tolerance regulation.

Genome-wide identification of YABBY transcription factors in Brachypodium distachyon and functional characterization of Bd DROOPING LEAF

YABBY transcription factors (TFs) are plant-specific and are characterized by a C2-C2 zinc finger domain at the N-terminus and a YABBY domain at the C-terminus. In this study, eight YABBY genes were identified in the Brachypodium distachyon genome and were unevenly distributed across four chromosomes. Phylogenetic analysis classified BdYABBYs into FIL/YAB3, YAB2, CRC, and INO clades. Sixty-two putative cis-elements were identified in BdYABBY gene putative promoters, among them, CAAT-box, TATA-box, MYB, MYC, ARE, and Box_4 were shared by all. BdYABBY genes are highly expressed in inflorescences, and abiotic stresses regulate their expression. In addition, three transcripts of BdDL were identified. Over-expression in Arabidopsis has shown their different functions in reproductive development, as well as in response to cold stress. Our study lays the foundation for the functional elucidation of BdYABBY genes.

Genome-Wide Identification of the Eucalyptus urophylla GATA Gene Family and Its Diverse Roles in Chlorophyll Biosynthesis

GATA transcription factors have been demonstrated to play key regulatory roles in plant growth, development, and hormonal response. However, the knowledge concerning the evolution of GATA genes in Eucalyptus urophylla and their trans-regulatory interaction is indistinct. Phylogenetic analysis and study of conserved motifs, exon structures, and expression patterns resolved the evolutionary relationships of these GATA proteins. Phylogenetic analysis showed that EgrGATAs are broadly distributed in four subfamilies. Cis-element analysis of promoters revealed that EgrGATA genes respond to light and are influenced by multiple hormones and abiotic stresses. Transcriptome analysis revealed distinct temporal and spatial expression patterns of EgrGATA genes in various tissues of E. urophylla S.T.Blake, which was confirmed by real-time quantitative PCR (RT-qPCR). Further research revealed that EurGNC and EurCGA1 were localized in the nucleus, and EurGNC directly binds to the cis-element of the EurGUN5 promoter, implying its potential roles in the regulation of chlorophyll synthesis. This comprehensive study provides new insights into the evolution of GATAs and could help to improve the photosynthetic assimilation and vegetative growth of E. urophylla at the genetic level.

Selection and validation of reference genes for quantitative real-time PCR of Quercus mongolica Fisch. ex Ledeb under abiotic stresses

Quercus mongolica Fisch. ex Ledeb is the main species of coniferous and broadleaved mixed forests in northeast and north China, which has high ornamental, economic, and ecological value. The appropriate reference genes must be selected for quantitative real-time PCR to reveal the molecular mechanisms of stress responses and their contribution to breeding of Q. mongolica. In the present study, we chose 11 candidate reference genes (TUA, CYP18, HIS4, RPS13, ACT97, TUB1, UBQ10, UBC5, SAND, PP2A, and SAMDC) and used four programs (GeNorm, NormFinder, BestKeeper, and RefFinder) to assess the expression stability of the above genes in roots, stems, and leaves under five abiotic stress factors (cold, salt, drought, weak light, and heavy metal). The findings revealed that under various experimental environments, the most stable genes were different; CYP18, ACT97, and RPS13 ranked the highest under most experimental environments. Moreover, two genes induced by stress, CMO and P5CS2, were chosen to demonstrate the reliability of the selected reference genes in various tissues under various stress conditions. Our research provides a significant basis for subsequent gene function studies of Q. mongolica.

Thaumatin-like Protein (TLP) Genes in Garlic (Allium sativum L.): Genome-Wide Identification, Characterization, and Expression in Response to Fusarium proliferatum Infection

Plant antifungal proteins include the pathogenesis-related (PR)-5 family of fungi- and other stress-responsive thaumatin-like proteins (TLPs). However, the information on the TLPs of garlic (Allium sativum L.), which is often infected with soil Fusarium fungi, is very limited. In the present study, we identified 32 TLP homologs in the A. sativum cv. Ershuizao genome, which may function in the defense against Fusarium attack. The promoters of A. sativumTLP (AsTLP) genes contained cis-acting elements associated with hormone signaling and response to various types of stress, including those caused by fungal pathogens and their elicitors. The expression of AsTLP genes in Fusarium-resistant and -susceptible garlic cultivars was differently regulated by F. proliferatum infection. Thus, in the roots the mRNA levels of AsTLP7–9 and 21 genes were increased in resistant and decreased in susceptible A. sativum cultivars, suggesting the involvement of these genes in the garlic response to F. proliferatum attack. Our results provide insights into the role of TLPs in garlic and may be useful for breeding programs to increase the resistance of Allium crops to Fusarium infections.

Molecular Details of Actinomycin D-Treated MRSA Revealed via High-Dimensional Data

Methicillin-resistant Staphylococcus aureus (MRSA) is highly concerning as a principal infection pathogen. The investigation of higher effective natural anti-MRSA agents from marine Streptomyces parvulus has led to the isolation of actinomycin D, that showed potential anti-MRSA activity with MIC and MBC values of 1 and 8 μg/mL, respectively. Proteomics-metabolomics analysis further demonstrated a total of 261 differential proteins and 144 differential metabolites induced by actinomycin D in MRSA, and the co-mapped correlation network of omics, indicated that actinomycin D induced the metabolism pathway of producing the antibiotic sensitivity in MRSA. Furthermore, the mRNA expression levels of the genes acnA, ebpS, clfA, icd, and gpmA related to the key differential proteins were down-regulated measured by qRT-PCR. Molecular docking predicted that actinomycin D was bound to the targets of the two key differential proteins AcnA and Icd by hydrogen bonds and interacted with multiple amino acid residues of the proteins. Thus, these findings will provide a basic understanding to further investigation of actinomycin D as a potential anti-MRSA agent.

Integrated Transcriptome Analysis and Single-Base Resolution Methylomes of Watermelon (Citrullus lanatus) Reveal Epigenome Modifications in Response to Osmotic Stress

DNA methylation plays an important role against adverse environment by reshaping transcriptional profile in plants. To better understand the molecular mechanisms of watermelon response to osmotic stress, the suspension cultured watermelon cells were treated with 100mM mannitol, and then a methylated cytosines map was generated by whole genome bisulfite sequencing (WGBS). Combined with transcriptome sequencing, the effects of osmotic stress on differentially methylated expressed genes (DMEGs) were assessed. It was found that genes related to plant hormone synthesis, signal transduction, osmoregulatory substance-related and reactive oxygen species scavenging-related enzyme could rapidly respond to osmotic stress. The overall methylation level of watermelon decreased after osmotic stress treatment, and demethylation occurred in CG, CHG, and CHH contexts. Moreover, differentially methylated expressed genes (DMEGs) were significantly enriched in RNA transport, starch and sucrose metabolism, plant hormone signal transduction and biosynthesis of secondary metabolites, especially in biosynthesis of osmolytes synthase genes. Interestingly, demethylation of a key enzyme gene Cla014489 in biosynthesis of inositol upregulated its expression and promoted accumulation of inositol, which could alleviate the inhibition of cell growth caused by osmotic stress. Meanwhile, a recombinant plasmid pET28a-Cla014489 was constructed and transferred into Escherichia coli BL21 for prokaryotic expression and the expression of ClMIPS protein could improve the tolerance of E. coli to osmotic stress. The effect of methylation level on the expression properties of inositol and its related genes was further confirmed by application of DNA methylation inhibitor 5-azacytidine. These results provide a preliminary insight into the altered methylation levels of watermelon cells in response to osmotic stress and suggest a new mechanism that how watermelon cells adapt to osmotic stress.

Mangrovivirga cuniculi gen. nov., sp. nov., a moderately halophilic bacterium isolated from bioturbated Red Sea mangrove sediment, and proposal of the novel family Mangrovivirgaceae fam. nov

A strictly aerobic, Gram-stain-negative, non-motile, rod-shaped bacterium, designated strain R1DC9^T, was isolated from sediments of a mangrove stand on the Red Sea coast of Saudi Arabia via diffusion chamber cultivation. Strain R1DC9^T grew at 20-40 °C (optimum, 37 °C), pH 6-10 (optimum, pH 8) and 3-11 % NaCl (optimum, 7-9 %) in the cultivation medium. The genome of R1DC9^T was 4 661 901 bp long and featured a G+C content of 63.1 mol%. Phylogenetic analyses based on the 16S rRNA gene sequence and whole-genome multilocus sequence analysis using 120 concatenated single-copy genes revealed that R1DC9^T represents a distinct lineage in the order Cytophagales and the phylum Bacteroidetes separated from the Roseivirgaceae and Marivirgaceae families. R1DC9^T displayed 90 and 89 % 16S rRNA gene sequence identities with Marivirga sericea DSM 4125^T and Roseivirga ehrenbergii KMM 6017^T, respectively. The predominant quinone was MK7. The polar lipids were phosphatidylethanolamine, two unknown phospholipids and two unknown lipids. The predominant cellular fatty acids were the saturated branch chain fatty acids iso-C_15 : 0, iso-C_17 : 0 3-OH and iso-C_17 : 0, along with a low percentage of the monounsaturated fatty acid C_16 : 1  ω5c. Based on differences in phenotypic, physiological and biochemical characteristics from known relatives, and the results of phylogenetic analyses, R1DC9^T (=KCTC 72349^T=JCM 33609^T=NCCB 100698^T) is proposed to represent a novel species in a new genus, and the name Mangrovivirga cuniculi gen. nov., sp. nov. is proposed. The distinct phylogenetic lineage among the families in the order Cytophagales indicates that R1DC9^T represents a new family for which the name Mangrovivirgaceae fam. nov. is proposed.

Osmoregulation and its actions during the drought stress in plants

Drought stress, which causes a decline in quality and quantity of crop yields, has become more accentuated these days due to climatic change. Serious measures need to be taken to increase the tolerance of crop plants to acute drought conditions likely to occur due to global warming. Drought stress causes many physiological and biochemical changes in plants, rendering the maintenance of osmotic adjustment highly crucial. The degree of plant resistance to drought varies with plant species and cultivars, phenological stages of the plant, and the duration of plant exposure to the stress. Osmoregulation in plants under low water potential relies on synthesis and accumulation of osmoprotectants or osmolytes such as soluble proteins, sugars, and sugar alcohols, quaternary ammonium compounds, and amino acids, like proline. This review highlights the role of osmolytes in water-stressed plants and of enzymes entailed in their metabolism. It will be useful, especially for researchers working on the development of drought-resistant crops by using the metabolic-engineering techniques.

In silico characterization and homology modeling of cytosolic APX gene predicts novel glycine residue modulating waterlogging stress response in pigeon pea

Ascorbate peroxidase (APX) is a member of the family of heme-containing peroxidases having a similar structure with Cytochrome c peroxidase (CCP) that effectively scavenge cytosolic and chloroplastic hydrogen peroxide (H₂O₂) under various stresses. In this study, computational characterization and homology analysis of APX protein from waterlogging tolerant (ICPL 84023) and sensitive (ICP 7035) pigeon pea genotypes were carried out resulting in 100% homology with Glycine max in case of former and 99% in later genotypes respectively with 97.39% alignment coverage among each other. The model structure was further refined by various tools like PROCHECK, ProSA, and Verify3D. The planned model of the APX enzyme was then tested to dock with H₂O₂along with molecular dynamics (MD) simulation analysis. The docked complex of ICPL 84023 showed the best G-score (23.39 kcal/mol) in comparison to ICP 7035 (16.74 kcal/mol) depicting the higher production of APX for scavenging reactive oxygen species (ROS) production making this genotype more tolerant. The important binding residues in the ICPL 84023-H₂O₂complex (SER1, THR4, GLU23, and GLY13) have shown less fluctuation than the ICP 7035-H₂O₂ complex (SER1, THR4, and GLU23). Overall, our results showed that amino acid residue glycine in ICPL 84023 APX gene has a high binding affinity with H₂O₂ which could be a key factor associated with waterlogging stress tolerance in pigeon pea.

Genome-Wide Analysis of the DUF4228 Family in Soybean and Functional Identification of GmDUF4228 -70 in Response to Drought and Salt Stresses

Domain of unknown function 4228 (DUF4228) proteins are a class of proteins widely found in plants, playing an important role in response to abiotic stresses. However, studies on the DUF4228 family in soybean (Glycine max L.) are sparse. In this study, we identified a total of 81 DUF4228 genes in soybean genome, named systematically based on their chromosome distributions. Results showed that these genes were unevenly distributed on the 20 chromosomes of soybean. The predicted soybean DUF4228 proteins were identified in three groups (Groups I-III) based on a maximum likelihood phylogenetic tree. Genetic structure analysis showed that most of the GmDUF4228 genes contained no introns. Expression profiling showed that GmDUF4228 genes were widely expressed in different organs and tissues in soybean. RNA-seq data were used to characterize the expression profiles of GmDUF4228 genes under the treatments of drought and salt stresses, with nine genes showing significant up-regulation under both drought and salt stress further functionally verified by promoter (cis-acting elements) analysis and quantitative real-time PCR (qRT-PCR). Due to its upregulation under drought and salt stresses based on both RNA-seq and qRT-PCR analyses, GmDUF4228-70 was selected for further functional analysis in transgenic plants. Under drought stress, the degree of leaf curling and wilting of the GmDUF4228-70-overexpressing (GmDUF4228-70-OE) line was lower than that of the empty vector (EV) line. GmDUF4228-70-OE lines also showed increased proline content, relative water content (RWC), and chlorophyll content, and decreased contents of malondialdehyde (MDA), H2O2, and O2-. Under salt stress, the changes in phenotypic and physiological indicators of transgenic plants were the same as those under drought stress. In addition, overexpression of the GmDUF4228-70 gene promoted the expression of marker genes under both drought and salt stresses. Taken together, the results indicated that GmDUF4228 genes play important roles in response to abiotic stresses in soybean.

Glycine betaine functionalized graphene oxide as a new engineering nanoparticle lessens salt stress impacts in sweet basil (Ocimum basilicum L.)

Regarding destructive impacts of salinity on different vital processes of plants, many strategies have been developed to alleviate salinity effects. Amongst, nanoparticles (NPs) application has been achieved great attention. For that point, considering positive effects of graphene oxide NPs (GO) and glycine betaine (GB) on different plant processes, GO-GB NPs were primarily synthesized to use GO as a carrier for GB. Then, GO, GB and GO-GB (each in three concentrations; 0, 50 and 100 mg L^-1) were applied on sweet basil (Ocimum basilicum L.) plants under 0, 50 and 100 mM salinity stress conditions. The results demonstrated that GO-GB NPs could lessen negative effects of salinity by enhancing agronomic traits, photosynthetic pigments, chlorophyll fluorescence parameters, membrane stability index (MSI), proline, phenols, antioxidant enzymes activities and dominant constituents of essential oils and decreasing MDA and H₂O₂. These positive effects were more considerable at its lower dose (50 mg L^-1) introducing it as the best treatment to ameliorate sweet basil performance especially essential oil compounds under salt stress. GO application at its higher dose (100 mg L^-1) demonstrated toxicity by negative impacts on the measured parameters. In conclusion, the positive response of sweet basil to GO-GB NPs under non-stress and salt stress conditions cause to consider the NPs as potential novel plant growth promoting and stress protecting agent with innovative outlooks for its use in agriculture.

Betaine Aldehyde Dehydrogenase (BADH) vs. Flavodoxin (Fld): Two Important Genes for Enhancing Plants Stress Tolerance and Productivity

Abiotic stresses, mainly salinity and drought, are the most important environmental threats that constrain worldwide food security by hampering plant growth and productivity. Plants cope with the adverse effects of these stresses by implementing a series of morpho-physio-biochemical adaptation mechanisms. Accumulating effective osmo-protectants, such as proline and glycine betaine (GB), is one of the important plant stress tolerance strategies. These osmolytes can trigger plant stress tolerance mechanisms, which include stress signal transduction, activating resistance genes, increasing levels of enzymatic and non-enzymatic antioxidants, protecting cell osmotic pressure, enhancing cell membrane integrity, as well as protecting their photosynthetic apparatus, especially the photosystem II (PSII) complex. Genetic engineering, as one of the most important plant biotechnology methods, helps to expedite the development of stress-tolerant plants by introducing the key tolerance genes involved in the biosynthetic pathways of osmolytes into plants. Betaine aldehyde dehydrogenase (BADH) is one of the important genes involved in the biosynthetic pathway of GB, and its introduction has led to an increased tolerance to a variety of abiotic stresses in different plant species. Replacing down-regulated ferredoxin at the acceptor side of photosystem I (PSI) with its isofunctional counterpart electron carrier (flavodoxin) is another applicable strategy to strengthen the photosynthetic apparatus of plants under stressful conditions. Heterologous expression of microbially-sourced flavodoxin (Fld) in higher plants compensates for the deficiency of ferredoxin expression and enhances their stress tolerance. BADH and Fld are multifunctional transgenes that increase the stress tolerance of different plant species and maintain their production under stressful situations by protecting and enhancing their photosynthetic apparatus. In addition to increasing stress tolerance, both BADH and Fld genes can improve the productivity, symbiotic performance, and longevity of plants. Because of the multigenic and complex nature of abiotic stresses, the concomitant delivery of BADH and Fld transgenes can lead to more satisfying results in desired plants, as these two genes enhance plant stress tolerance through different mechanisms, and their cumulative effect can be much more beneficial than their individual ones. The importance of BADH and Fld genes in enhancing plant productivity under stress conditions has been discussed in detail in the present review.

Comparative Study of Drought Stress Effects on Traditional and Modern Apple Cultivars

Genotype-dependent responses of apples to drought stress were evaluated between commercial and traditional apple cultivars. The results indicate different mechanisms of tolerance to investigated drought stress conditions. Chlorophyll fluorescence induction (OJIP) parameters, chlorophyll and carotenoid content, malondialdehyde (MDA), hydrogen peroxide (H2O2), proline, phenols and leaf water content (WC) were measured. The traditional cultivar "Crvenka" confirmed the best tolerance to a drought stress condition, presenting higher photosynthetic efficiency, higher leaf water content, higher levels of chlorophyll content and lower lipid peroxidation with greater membrane stability. The commercial cultivar "Golden Delicious Reinders" showed decreased water content in leaves, increased lipid peroxidation levels and photoinhibition. Considering all results, the commercial cultivar "Golden Delicious Reinders" was adversely affected by drought, while traditional cultivars exhibited better tolerance to drought stress.

Sodium nitroprusside mediated priming memory invokes water-deficit stress acclimation in wheat plants through physio-biochemical alterations

AIM

Water-deficit stress is the most devastating environmental factor that adversely affects plant growth causing yield losses and low crop productivity. In this study, we employed sodium nitroprusside (SNP) as a seed priming agent for the acclimation of water-deficit stress in wheat plants by invoking priming memory.

METHODS

The SNP-primed (75, 100, and 125 μM) and non-primed controls were allowed to grow in pots under water deficit and normal conditions. The flag leaves of 98-days mature plants were used for biochemical and physiological studies by following the well-established methods.

RESULTS

The antioxidant and hydrolytic enzymes were upregulated while reducing sugars, total sugars, and glycine betaine increased significantly in flag leaves of wheat plants originated from SNP-treated seeds compared to control under water deficit stress. However, a significant reduction in MDA and proline contents represented a lesser ROS production which resulted in enhanced cell membrane stability. Consequently, there was a significant enhancement in yield, plant biomass and 100 grains weight of wheat plants under water deficit stress.

CONCLUSION

The improvement in yield parameters indicates the induction of priming memory in SNP-primed seeds which elicit water deficit tolerance till the maturity of plants thus ensures sustainable productivity of wheat.

Citron Watermelon Potential to Improve Crop Diversification and Reduce Negative Impacts of Climate Change

Citron watermelon (Citrullus lanatus var. citroides (L.H. Bailey) Mansf. ex Greb.) is an underexploited and under-researched crop species with the potential to contribute to crop diversification in Sub-Saharan Africa. The species is cultivated in the drier parts of Southern Africa, mainly by smallholder farmers who maintain a wide range of landrace varieties. Understanding the molecular and morpho-physiological basis for drought adaptation in citron watermelon under these dry environments can aid in the identification of suitable traits for drought-tolerance breeding and improve food system resilience among smallholder farmers, thus adding to crop diversification. This paper reviews the literature on drought adaptation of Citrullus lanatus spp. (C3 xerophytes), using the systematic review approach. The review discusses the potential role of citron watermelon in adding to crop diversification, alternative food uses, and potential by-products that can be processed from the crop, and it analyzes the role of Sub-Saharan African farmers play as key actors in conserving citron watermelon germplasm and biodiversity. Finally, the review provides a summary of significant findings and identifies critical knowledge gaps for further research.

Silicon-Mediated Priming Induces Acclimation to Mild Water-Deficit Stress by Altering Physio-Biochemical Attributes in Wheat Plants

Water-deficit stress negatively affects seed germination, seedling development, and plant growth by disrupting cellular and metabolic functions, reducing the productivity and yield of field crops. In this study, sodium silicate (SS) has been employed as a seed priming agent for acclimation to mild water-deficit stress by invoking priming memory in wheat plants. In pot experiments, the SS-primed (20, 40, and 60 mM) and non-primed control seeds were allowed to grow under normal and mild water-deficit conditions. Subsequently, known methods were followed for physiological and biochemical studies using flag leaves of 98-day mature wheat plants. The antioxidant and hydrolytic enzymes were upregulated, while proteins, reducing sugars, total sugars, and glycine betaine increased significantly in the flag leaves of wheat plants originated from SS-treated seeds compared to the control under mild water-deficit stress. Significant decreases in the malondialdehyde (MDA) and proline contents suggested a controlled production of reactive oxygen species, which resulted in enhanced cell membrane stability. The SS priming induced a significant enhancement in yield, plant biomass, and 100-grain weight of wheat plants under water-deficit stress. The improvement in the yield parameters indicated the induction of Si-mediated stress acclimation in SS-primed seeds that elicited water-deficit tolerance until the maturity of plants, ensuring sustainable productivity of climate-smart plants.

Integration of Gas Exchange With Metabolomics: High-Throughput Phenotyping Methods for Screening Biostimulant-Elicited Beneficial Responses to Short-Term Water Deficit

Biostimulants are emerging as a feasible tool for counteracting reduction in climate change-related yield and quality under water scarcity. As they are gaining attention, the necessity for accurately assessing phenotypic variables in their evaluation is emerging as a critical issue. In light of this, high-throughput phenotyping techniques have been more widely adopted. The main bottleneck of these techniques is represented by data management, which needs to be tailored to the complex, often multifactorial, data. This calls for the adoption of non-linear regression models capable of capturing dynamic data and also the interaction and effects between multiple factors. In this framework, a commercial glycinebetaine- (GB-) based biostimulant (Vegetal B60, ED&F Man) was tested and distributed at a rate of 6 kg/ha. Exogenous application of GB, a widely accumulated and documented stress adaptor molecule in plants, has been demonstrated to enhance the plant abiotic stress tolerance, including drought. Trials were conducted on tomato plants during the flowering stage in a greenhouse. The experiment was designed as a factorial combination of irrigation (water-stressed and well-watered) and biostimulant treatment (treated and control) and adopted a mixed phenotyping-omics approach. The efficacy of a continuous whole-canopy multichamber system coupled with generalized additive mixed modeling (GAMM) was evaluated to discriminate between water-stressed plants under the biostimulant treatment. Photosynthetic performance was evaluated by using GAMM, and was then correlated to metabolic profile. The results confirmed a higher photosynthetic efficiency of the treated plants, which is correlated to biostimulant-mediated drought tolerance. Furthermore, metabolomic analyses demonstrated the priming effect of the biostimulant for stress tolerance and detoxification and stabilization of photosynthetic machinery. In support of this, the overaccumulation of carotenoids was particularly relevant, given their photoprotective role in preventing the overexcitation of photosystem II. Metabolic profile and photosynthetic performance findings suggest an increased effective use of water (EUW) through the overaccumulation of lipids and leaf thickening. The positive effect of GB on water stress resistance could be attributed to both the delayed onset of stress and the elicitation of stress priming through the induction of H₂O₂-mediated antioxidant mechanisms. Overall, the mixed approach supported by a GAMM analysis could prove a valuable contribution to high-throughput biostimulant testing.

Characterization and Stress Response of the JmjC Domain-Containing Histone Demethylase Gene Family in the Allotetraploid Cotton Species Gossypium hirsutum

Histone modification is an important epigenetic modification that controls gene transcriptional regulation in eukaryotes. Histone methylation is accomplished by histone methyltransferase and can occur on two amino acid residues, arginine and lysine. JumonjiC (JmjC) domain-containing histone demethylase regulates gene transcription and chromatin structure by changing the methylation state of the lysine residue site and plays an important role in plant growth and development. In this study, we carried out genome-wide identification and comprehensive analysis of JmjC genes in the allotetraploid cotton species Gossypium hirsutum. In total, 50 JmjC genes were identified and in G. hirsutum, and 25 JmjC genes were identified in its two diploid progenitors, G. arboreum and G. raimondii, respectively. Phylogenetic analysis divided these JmjC genes into five subfamilies. A collinearity analysis of the two subgenomes of G. hirsutum and the genomes of G. arboreum and G. raimondii uncovered a one-to-one relationship between homologous genes of the JmjC gene family. Most homologs in the JmjC gene family between A and D subgenomes of G. hirsutum have similar exon-intron structures, which indicated that JmjC family genes were conserved after the polyploidization. All G. hirsutumJmjC genes were found to have a typical JmjC domain, and some genes also possess other special domains important for their function. Analysis of promoter regions revealed that cis-acting elements, such as those related to hormone and abiotic stress response, were enriched in G. hirsutum JmjC genes. According to a reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis, most G. hirsutumJmjC genes had high abundance expression at developmental stages of fibers, suggesting that they might participate in cotton fiber development. In addition, some G. hirsutumJmjC genes were found to have different degrees of response to cold or osmotic stress, thus indicating their potential role in these types of abiotic stress response. Our results provide useful information for understanding the evolutionary history and biological function of JmjC genes in cotton.

Physiological and Biochemical Changes in Sugar Beet Seedlings to Confer Stress Adaptability under Drought Condition

The present study was conducted to examine the adaptability of 11 sugar beet cultivars grown under drought stress in the controlled glasshouse. The treatment was initiated on 30-day-old sugar beet plants where drought stress was made withholding water supply for consecutive 10 days while control was done with providing water as per requirement. It was observed that drought stress expressively reduced plant growth, photosynthetic pigments, and photosynthetic quantum yield in all the cultivars but comparative better results were observed in S1 (MAXIMELLA), S2 (HELENIKA), S6 (RECODDINA), S8 (SV2347), and S11 (BSRI Sugarbeet 2) cultivars. Besides, osmolytes like proline, glycine betaine, total soluble carbohydrate, total soluble sugar, total polyphenol, total flavonoid, and DPPH free radical scavenging activity were remarkably increased under drought condition in MAXIMELLA, HELENIKA, TERRANOVA, GREGOIA, SV2348, and BSRI Sugar beet 2 cultivars. In contrast, activities of enzymes like superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were significantly decreased in all, while the cultivars SV2347, BSRI Sugar beet 1 and BSRI Sugar beet 2 were found with increased ascorbate peroxidase (APX) activity under drought condition. In parallel, polyphenol oxidase (PPO) was increased in all cultivars except HELENIKA. Overall, the cultivars HELENIKA, RECODDINA, GREGOIA, SV2347, SV2348, BSRI Sugar beet 1, and BSRI Sugar beet 2 were found best fitted to the given drought condition. These findings would help further for the improvement of stress adaptive sugar beet cultivars development in the breeding program for drought-prone regions.

Insight into the relationship between S-lignin and fiber quality based on multiple research methods

Cotton (Gossypium hirsutum) is an important cash crop, providing people with high quality natural fiber. Lignin is the main component of cotton fiber, second only to cellulose. As a main substance filled in the cellulose framework during the secondary wall thickening process, lignin plays a key role in the formation of cotton fiber quality. However, the mechanism behind it is still unclear. In this research, we screened candidate genes involved in lignin biosynthesis based on analysis of cotton genome and transcriptome sequence data. The authenticity of the transcriptome data was verified by qRT-PCR assay. Total 62 genes were identified from nine gene families. In the process, we found the key gene GhCAD7 that affects the biosynthesis of S-lignin and the ratio of syringyl/guaiacyl (S/G). In addition, in combination with the metabolites and transcriptome profiles of the line 0-153 with high fiber quality and the line sGK9708 with low fiber quality during cotton fiber development, we speculate that the ratio of syringyl/guaiacyl (S/G) is inseparable from the quality of cotton fiber. Finally, the S-type lignin synthesis branch may play a more important role in the formation of high-quality fiber. This work provides insights into the synthesis of lignin in cotton and lays the foundation for future research into improving fiber quality.

Virological Response to Sofosbuvir-Based Treatment in Renal Transplant Recipients With Hepatitis C in Pakistan

OBJECTIVES

Direct-acting antiviral agents have recently been recommended in renal transplant recipients. Considering our previous encouraging responses with combined sofosbuvir and ribavirin in renal transplant recipients and the availability of daclatasvir, we aimed to evaluate the effectiveness and safety of sofosbuvir-based direct-acting antiviral agents in our population.

MATERIALS AND METHODS

All renal transplant recipients who received sofosbuvir-based direct-acting antivirals from August 2015 to March 2018 were included in our study. Patients were treated with sofosbuvir and ribavirin for 24 weeks or with combined sofosuvir, daclatasvir, and ribavirin for 12 weeks. Patient demographics and baseline laboratory parameters were collected. Rapid virologic response, end of treatment response, and sustained virologic response at 12 weeks were analyzed. Statistical analyses were performed with SPSS software (SPSS: An IBM Company, version 20.0, IBM Corporation, Armonk, NY, USA).

RESULTS

In our study group of 79 patients, mean age was 36.5 ± 10.2 years and 60 were men (78.5%). Fiftysix patients (70.9%) were treatment naive; of the remaining patients, 20 received interferon before transplant and 3 were treated with sofosbuvir and ribavirin after renal transplant. Genotype 1 was observed in 42 patients (53.2%), whereas mixed genotype (1 and 3) was shown in 10 patients (12.6%). Sixty-two patients (78.5%) received sofosbuvir and ribavirin, and 17 patients (21.5%) received sofosbuvir, daclatasvir, and ribavirin. End of treatment response was achieved in 78 recipients (98.1%). Anemia was observed in 13 patients (16.4%).

CONCLUSIONS

Hepatitis C virus was successfully eradicated in renal transplant recipients who received a combination of sofosbuvir plus ribavirin or sofosbuvir, daclatasvir, and ribavirin. These combinations were effective and well tolerated in our study population, even in those with mixed genotype, with no major adverse events.

Antimicrobial Activity and Mechanism of Action of Dracocephalum moldavica L. Extracts Against Clinical Isolates of Staphylococcus aureus

Background: Dracocephalum moldavica L. is a popular traditional medicine used by many countries, which has a wide range of pharmacological effects. The aim of this work was to investigate the antimicrobial effects of D. moldavica L. extracts against clinical isolates of Staphylococcus aureus. Our results demonstrated that the minimal inhibitory concentration (MIC) for 50 and 90% of S. aureus isolates (MIC₅₀ and MIC₉₀) of the ethyl acetate (EtOAc) fraction from D. moldavica L. ethanol extract were 780 and 1,065 μg/ml, respectively. We further observed that the EtOAc fraction disrupted 24-h biofilm caused cell membrane damage and irregular cell shape. Additionally, the EtOAc fraction showed slight to moderate toxic effects on human epidermal keratinocyte (HaCaT) cells. Moreover, the results of the differential proteome revealed that 231 proteins were upregulated, while 61 proteins were downregulated in S. aureus after treatment with the EtOAc fraction. The differentially expressed proteins were functionally categorized by the Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. These proteins contribute to membrane damage, inhibition of biofilm formation, and changes in energy metabolism. Thus, the EtOAc fraction of D. moldavica L. ethanol extract, as a natural product, has the potential to be used as an antimicrobial agent to control the clinical isolates of S. aureus.

Spatial and Temporal Profile of Glycine Betaine Accumulation in Plants Under Abiotic Stresses

Several halophytes and a few crop plants, including Poaceae, synthesize and accumulate glycine betaine (GB) in response to environmental constraints. GB plays an important role in osmoregulation, in fact, it is one of the main nitrogen-containing compatible osmolytes found in Poaceae. It can interplay with molecules and structures, preserving the activity of macromolecules, maintaining the integrity of membranes against stresses and scavenging ROS. Exogenous GB applications have been proven to induce the expression of genes involved in oxidative stress responses, with a restriction of ROS accumulation and lipid peroxidation in cultured tobacco cells under drought and salinity, and even stabilizing photosynthetic structures under stress. In the plant kingdom, GB is synthesized from choline by a two-step oxidation reaction. The first oxidation is catalyzed by choline monooxygenase (CMO) and the second oxidation is catalyzed by NAD+-dependent betaine aldehyde dehydrogenase. Moreover, in plants, the cytosolic enzyme, named N-methyltransferase, catalyzes the conversion of phosphoethanolamine to phosphocholine. However, changes in CMO expression genes under abiotic stresses have been observed. GB accumulation is ontogenetically controlled since it happens in young tissues during prolonged stress, while its degradation is generally not significant in plants. This ability of plants to accumulate high levels of GB in young tissues under abiotic stress, is independent of nitrogen (N) availability and supports the view that plant N allocation is dictated primarily to supply and protect the growing tissues, even under N limitation. Indeed, the contribution of GB to osmotic adjustment and ionic and oxidative stress defense in young tissues, is much higher than that in older ones. In this review, the biosynthesis and accumulation of GB in plants, under several abiotic stresses, were analyzed focusing on all possible roles this metabolite can play, particularly in young tissues.