Accumulation Of Glycine Betaine Research Articles

Foliar Spray of Alpha-Tocopherol Modulates Antioxidant Potential of Okra Fruit under Salt Stress.

As an antioxidant, alpha-tocopherol (α-Toc) protects plants from salinity-induced oxidative bursts. This study was conducted twice to determine the effect of α-Toc as a foliar spray (at 0 (no spray), 100, 200, and 300 mg L−1) to improve the yield and biochemical constituents of fresh green capsules of okra (Abelmoschus esculentus L. Moench) under salt stress (0 and 100 mM). Salt stress significantly reduced K+ and Ca2+ ion concentration and yield, whereas it increased H2O2, malondialdehyde (MDA), Na+, glycine betaine (GB), total free proline, total phenolics, and the activities of catalase (CAT), guaiacol peroxidase (GPX), and protease in both okra varieties (Noori and Sabzpari). Foliar application of α-Toc significantly improved the yield in tested okra varieties by increasing the activity of antioxidants (CAT, GPX, SOD, and ascorbic acid), accumulation of GB, and total free proline in fruit tissues under saline and non-saline conditions. Moreover, α-Toc application as a foliar spray alleviated the adverse effects of salt stress by reducing Na+ concentration, MDA, and H2O2 levels and improving the uptake of K+ and Ca2+. Among the tested okra varieties, Noori performed better than Sabzpari across all physio-biochemical attributes. Of all the foliar-applied α-Toc levels, 200 mg L−1 and 300 mg L−1 were more effective in the amelioration of salinity-induced adverse effects in okra. Thus, we concluded that higher levels of α-Toc (200 mg L−1 and 300 mg L−1) combat salinity stress more effectively by boosting the antioxidant potential of okra plants.

Control of Elevated Ion Accumulation, Oxidative Stress, and Lipid Peroxidation with Salicylic Acid-Induced Accumulation of Glycine Betaine in Salinity-Exposed Vigna radiata L.

The identification of the sustainable approaches is required for the minimization of adverse impact of worldwide increasing soil salinity on plant growth, development, and productivity. This study investigated the protective role and major mechanism underlying salicylic acid (SA; 0.1, 0.5, or 1.0 mM)-induced glycine betaine (GB)-mediated tolerance to salinity (50 mM NaCl) in mungbean (Vigna radiata L. cultivar Punt Mung). The supply of 0.5 mM SA maximally increased the accumulation of GB (>40%) with respect to the control. This was further corroborated with the increase in water potential, antioxidant system (reduced glutathione (GSH), GSH/GSSG redox state, and glutathione reductase (GR) activity) and decreased Na+ and Cl- accumulation, Na+/K+ ratio, oxidative stress, and lipid peroxidation. This was also associated with the increased photosynthesis (14-18%) and growth (7-12%) parameters. Overall, SA-induced accumulation of GB protected photosynthesis and growth against 50 mM NaCl-accrued impacts in V. radiata through minimizing the accumulation of Na+ and Cl- ions, oxidative stress, and maintaining high GSH level that led to reduced cellular redox environment.

Promotion of Growth and Physiological Characteristics in Water-Stressed Triticum aestivum in Relation to Foliar-Application of Salicylic Acid

The present work reports the assessment of the effectiveness of a foliar-spray of salicylic acid (SA) on growth attributes, biochemical characteristics, antioxidant activities and osmolytes accumulation in wheat grown under control (100% field capacity) and water stressed (60% field capacity) conditions. The total available water (TAW), calculated for a rooting depth of 1.65 m was 8.45 inches and readily available water (RAW), considering a depletion factor of 0.55, was 4.65 inches. The water contents corresponding to 100 and 60% field capacity were 5.70 and 1.66 inches, respectively. For this purpose, seeds of two wheat cultivars (Fsd-2008 and S-24) were grown in pots subjected to water stress. Water stress at 60% field capacity markedly reduced the growth attributes, photosynthetic pigments, total soluble proteins (TSP) and total phenolic contents (TPC) compared with control. However, cv. Fsd-2008 was recorded as strongly drought-tolerant and performed better compared to cv. S-24, which was moderately drought tolerant. However, water stress enhanced the contents of malondialdehyde (MDA), hydrogen peroxide (H2O2) and membrane electrolyte leakage (EL) and modulated the activities of antioxidant enzymes (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), as well as accumulation of ascorbic acid (AsA), proline (Pro) and glycine betaine (GB) contents. Foliar-spray with salicylic acid (SA; 0, 3 mM and 6 mM) effectively mitigated the adverse effects of water stress on both cultivars. SA application at 6 mM enhanced the shoot and root length, as well as their fresh and dry weights, and improved photosynthetic pigments. SA foliage application further enhanced the activities of antioxidant enzymes (SOD, POD, and CAT) and nonenzymatic antioxidants such as ascorbic acid and phenolics contents. However, foliar-spray of SA reduced MDA, H2O2 and membrane permeability in both cultivars under stress conditions. The results of the present study suggest that foliar-spray of salicylic acid was effective in increasing the tolerance of wheat plants under drought stress in terms of growth attributes, antioxidant defense mechanisms, accumulation of osmolytes, and by reducing membrane lipid peroxidation.

Hydrogen sulfide: An emerging signaling molecule regulating drought stress response in plants.

Hydrogen sulfide (H2 S) is a small, reactive signaling molecule that is produced within chloroplasts of plant cells as an intermediate in the assimilatory sulfate reduction pathway by the enzyme sulfite reductase. In addition, H2 S is also produced in cytosol and mitochondria by desulfhydration of l-cysteine catalyzed by l-cysteine desulfhydrase (DES1) in the cytosol and from β-cyanoalanine in mitochondria, in a reaction catalyzed by β-cyano-Ala synthase C1 (CAS-C1). H2 S exerts its numerous biological functions by post-translational modification involving oxidation of cysteine residues (RSH) to persulfides (RSSH). At lower concentrations (10-1000 μmol L-1 ), H2 S shows huge agricultural potential as it increases the germination rate, the size, fresh weight, and ultimately the crop yield. It is also involved in abiotic stress response against drought, salinity, high temperature, and heavy metals. H2 S donor, for example, sodium hydrosulfide (NaHS), has been exogenously applied on plants by various researchers to provide drought stress tolerance. Exogenous application results in the accumulation of polyamines, sugars, glycine betaine, and enhancement of the antioxidant enzyme activities in response to drought-induced osmotic and oxidative stress, thus, providing stress adaptation to plants. At the biochemical level, administration of H2 S donors reduces malondialdehyde content and lipoxygenase activity to maintain the cell integrity, causes abscisic acid-mediated stomatal closure to prevent water loss through transpiration, and accelerates the photosystem II repair cycle. Here, we review the crosstalk of H2 S with secondary messengers and phytohormones towards the regulation of drought stress response and emphasize various approaches that can be addressed to strengthen research in this area.

Improving the drying of Propionibacterium freudenreichii starter cultures.

Propionibacterium freudenreichii is a beneficial food-grade actinobacterium, widely implemented, and thus consumed, in various food products. As the main application, P. freudenreichii is used as a cheese-ripening starter, mostly in hard type cheeses. Indeed, during manufacture of "Swiss-type" cheeses (or opened-body cheeses), the technological process favors propionibacteria growth, as well as the corresponding propionic fermentation. This leads to the characteristic flavor of these cheeses, through the release of short chain fatty acids and through lipolysis, as well as to their specific texture. To fulfil this ripening, massive amounts of propionibacteria are industrially produced, dried and stored, prior to cheese making. Furthermore, P. freudenreichii is commercialized in various probiotic food supplements aiming at preserving intestinal health and comfort, in line with its ability to produce beneficial metabolites (short chain fatty acids, vitamins), as well as immunomodulatory compounds. Other industrial applications of P. freudenreichii include the production of food-grade vitamins of the B group, of trehalose, of conjugated linoleic acid, and of biopreservatives. For these different applications, maintaining survival and activity of propionibacteria during production, drying, storage and finally implementation, is crucial. More widely, maintaining live and active probiotic bacteria represents a challenge as the market for probiotic products increases. Probiotic bacteria are, for a bulk majority, freeze-dried, but spray drying is also more and more considered. Indeed, this process is both continuous and more cost-efficient, as it utilizes less energy compared to freeze-drying; on the other hand, it exposes bacteria to higher heat and oxidative stresses. Apart from process optimization and strain selection, it is possible to enhance the resistance of bacteria by taking advantage of their adaptation capacity. Indeed, P. freudenreichii stress tolerance can be boosted by different pretreatments applied before the drying step, thus considerably increasing its final survival. In particular, adaptation to hyperosmotic conditions improves stress tolerance, while the presence of osmoprotectants may mitigate this improvement. Thermal adaptation also modulates tolerance towards these technological challenges. The composition of the growth medium, including the ratio between the carbohydrates provided and the non-protein nitrogen, plays a key role in driving the accumulation of osmoprotectants. This, in turn, determines P. freudenreichii tolerance towards different stresses, and overall towards both freeze-drying and spray-drying. As an example, the accumulation of trehalose enhances its spray-drying survival, while the accumulation of glycine betaine enhances its freeze-drying survival. Growth of propionibacteria in hyperconcentrated whey was used to trigger multiple stress tolerance acquisition, underpinned by overexpression of key stress protein, accumulation of cytoplasmic storage compounds, and leading to enhanced spray-drying survival. A simplified process, from cultivation to atomization, was developed by using whey as a 2-in-1 medium in which propionibacteria were grown, protected and dried with minimal cell death. This innovative process was then subjected to scaling up at the industrial level. In this aim, a gentle multi-stage drying process offering mild drying conditions by coupling spray drying with belt drying, led to final probiotic survival close to 100% when stress tolerance acquisition was previously implemented. Such innovation opens new avenues for the efficient, cost-effective and sustainable development of new probiotic production technologies, as well as probiotic application in the context of food and feed. KEY POINTS: • Propionibacteria acquire multi-stress tolerance when grown in hyper-concentrated whey. • Spray drying of osmo-adapted probiotic bacteria is possible with limited cell death. • A two-in-one drying method is developed to grow and dry probiotic bacteria in the same matrix.

Reaction to Hydrogen-Peroxide Action in Nicotiana tabacum Plants Transformed by the Cholinoxidase Gene (codA)

Genetic engineering of glycine betaine (GB) synthesis offers a new approach to improvements in the productivity and stress resistance of cultivated plants. The possible effect of the bacterial heterologous sequence on the reaction of plants under oxidative stress (OS) induced by 3 mM of hydrogen peroxide (H2O2) was determined. The independent transgenic tobacco lines (Nicotiana tabacum L.) Cod 16 and Cod 45 with the choline oxidase (codA) gene from Arthrobacter gloiformis, which is responsible for GB synthesis, were used. The transgenic lines differed from wild-type plants with lower resistance to H2O2, which led to a more significant decrease in the pool of photosynthetic pigments and a greater intensity of lipid peroxidation and dynamics of superoxide dismutase (SOD) and peroxidase (PO) activity. In terms of OS manifestation, transgenic lines with initially similar values of GB accumulation (0.825–0.910 mmol/g) had significant differences among themselves. In the Cod 16 line, the reaction to OS induction was earlier (1 h after H2O2 treatment), and there was a more significant increase in PO activity and proline content than in the Cod 45 line and the original variety. In the Cod 45 line, there is a significant increase in SOD activity and proline content in response to OS induction 24 h after treatment, and, in contrast to the wild-type plants and the Cod 16 line, it is accompanied by a significantly higher content of carotenoids in the leaves. When genetic-engineering methods are used to increase the productivity and resistance of plants to stress, it is necessary to take into account the functional interaction of antioxidants and osmoprotectors.

Overexpression of

Sugarcane (Saccharum hybrid) is an important industrial crop worldwide. Its growth and sucrose contents are severely affected by drought stress. Genetic engineering offers a rapid solution to improve tolerance level of sugarcane against this stress. This study was designed to transform sugarcane with the Tomato ethylene responsive factor 1 (TERF1) gene through Agrobacterium. Embryogenic callus of sugarcane cv. XintaitangR22 was used for transformation with Agrobacterium strain LBA4404 harbouring the pROK2 vector containing the TERF1 gene driven by the CaMV 35S promoter. Highest regeneration efficiency (74%) was obtained with inoculum density (OD600) at 0.4 and co-cultivated for 4 days on MS-based medium; 5.4% transformation efficiency was acquired from the regenerated plants. Successful insertion of the TERF1 gene into sugarcane was indicated by PCR-positive plants (n = 4). Expression of TERF1 transcripts in transgenic lines at various levels was detected by reverse transcriptase-PCR. Under normal conditions, growth status of transgenic lines was similar to that of wild-type plants; by contrast, only transgenic lines were able to withstand water-deficit stress conditions, showing tolerance against drought stress. Physiological and biochemical assays revealed that TERF1-overexpressed plants showed not only increased accumulation of proline, soluble sugars and glycine betaine but also reduced malondialdehyde and H2O2 content in response to drought stress. Our results revealed that overexpression of TERF1 in sugarcane conferred drought tolerance through increased accumulation of osmo-protectant, decreasing reactive oxygen species and malondialdehyde content, which possibly resulted from activation of expression of stress-related genes by TERF1 under stress. These findings indicate that the gene might have a regulatory role in the response to drought stress in sugarcane.

The JA‐responsive MYC2‐BADH‐like transcriptional regulatory module in Poncirus trifoliata contributes to cold tolerance by modulation of glycine betaine biosynthesis

Glycine betaine (GB) is known to accumulate in plants exposed to cold, but the underlying molecular mechanisms and associated regulatory network remain unclear. Here, we demonstrated that PtrMYC2 of Poncirus trifoliata integrates the jasmonic acid (JA) signal to modulate cold-induced GB accumulation by directly regulating PtrBADH-l, a betaine aldehyde dehydrogenase (BADH)-like gene. PtrBADH-l was identified based on transcriptome and expression analysis in P. trifoliata. Overexpression and VIGS (virus-induced gene silencing)-mediated knockdown showed that PtrBADH-l plays a positive role in cold tolerance and GB synthesis. Yeast one-hybrid library screening using PtrBADH-l promoter as baits unraveled PtrMYC2 as an interacting candidate. PtrMYC2 was confirmed to directly bind to two G-box cis-acting elements within PtrBADH-l promoter and acts as a transcriptional activator. In addition, PtrMYC2 functions positively in cold tolerance through modulation of GB synthesis by regulating PtrBADH-l expression. Interestingly, we found that GB accumulation under cold stress was JA-dependent and that PtrMYC2 orchestrates JA-mediated PtrBADH-l upregulation and GB accumulation. This study sheds new light on the roles of MYC2 homolog in modulating GB synthesis. In particular, wepropose a transcriptional regulatory module PtrMYC2-PtrBADH-l to advance the understanding of molecular mechanisms underlying the GB accumulation under cold stress.

GmNAC06, a NAC domain transcription factor enhances salt stress tolerance in soybean

Key messageWe found GmNAC06 plays an important role in salt stress responses through the phenotypic, physiological and molecular analyses of OE, VC, and Mutant composite soybean.Salinization affects 20% of all cultivated land worldwide because of the high salinity of irrigation water and the excessive use of water, and this amount is increasing daily. NAC (NAM, ATAF, and CUC) have been found to be involved in salt stress. In this study, a soybean NAC gene, GmNAC06 (Glyma06g21020.1), was cloned and functionally characterized. The results of expression analysis suggested that salt stress could influence the expression level of GmNAC06. The subcellular localization analysis results suggested that GmNAC06 may function as a transcription factor. Under salt stress, the overexpression technology combined with CRISPR-Cas9 system found that GmNAC06 could cause the accumulation of proline and glycine betaine to alleviate or avoid the negative effects of ROS; similarly, it could control the Na+/K+ ratios in hairy roots to maintain ionic homeostasis. The fresh weight of the transgenic hairy roots and the histochemical ROS staining of wild leaves suggested that transgenic hairy roots influence the function of wild leaves under salt stress conditions. Moreover, the expression levels of GmUBC2 and GmHKT1 were higher in the GmNAC06 hairy roots than in the control. Thus, the overexpression of GmNAC06 in hairy roots notably causes an entire composite plant to exhibit salt tolerance. The phenotype of composite soybean plants and transgenic Arabidopsis plants suggest that GmNAC06 plays a role in response to salt stress and could be useful in generating salt tolerant transgenic crops.

Naringenin induces tolerance to salt/osmotic stress through the regulation of nitrogen metabolism, cellular redox and ROS scavenging capacity in bean plants

The present study was conducted to uncover underlying possible effect mechanisms of flavonoid naringenin (Nar, 0.1–0.4 mM) in nitrogen assimilation, antioxidant response, redox status and the expression of NLP7 and DREB2A, on salt (100 mM NaCl) and osmotic-stressed (10% Polyethylene glycol, −0.54 MPa) Phaseolus vulgaris cv. Yunus 90). Nar ameliorated salt/osmotic stresses-induced growth inhibition and improved the accumulation of proline, glycine betaine and choline. In response to stress, Nar increased endogenous content of nitrate (NO3−) and nitrite (NO2−) by regulating of nitrate reductase and nitrite reductase. Stress-triggered NH4+ was eliminated with Nar through increases in glutamine synthetase and glutamate synthase. After NaCl or NaCl + PEG exposure, Nar utilized the aminating activity of glutamate dehydrogenase in the conversion of NH4+. The stress-inducible expression levels of DREB2A were increased further by Nar, which might have affected stress tolerance of bean. Nar induced effectively the relative expression of NLP7 in the presence of the combination or alone of stress. Also, the impaired redox state by stress was modulated by Nar and hydrogen peroxide (H2O2) and TBARS decreased. Nar regulated the different pathways for scavenging of H2O2 under NaCl and/or PEG treatments. When Nar + NaCl exposure, the damage was removed by superoxide dismutase (SOD), catalase (CAT), POX (only at 0.1 mM Nar + NaCl) and AsA-GSH cycle. Under osmotic stress plus Nar, the protection was manifested by activated CAT and, glutathione S-transferase and the regeneration of ascorbate. 0.1 mM Nar could protect bean plant against salt/osmotic stresses, likely by regulating nitrogen assimilation pathways, improving expression levels of genes associated with tolerance mechanisms and modulating the antioxidant capacity and AsA-GSH redox-based systems.

Drought tolerance in high-generation transgenic maize inbred lines overexpressing the betaine aldehyde dehydrogenase gene

Abiotic stress such as drought seriously endangers maize growth and production. Glycine betaine (GB) accumulation in transgenic crops following heterologous overexpression of the BADH gene has been shown to dramatically improve the tolerance to salt, cold, and oxidative stresses, but it is unclear if GB accumulation leads to improved drought tolerance of maize. In this study, we analyzed the drought tolerance of high-generation BADH transgenic maize inbred lines at different growth stages using the hyperosmotic solution and water-withholding methods. Molecular detection revealed that exogenous BADH was successfully introduced into the maize plant genome and overexpressed in three transgenic maize inbred lines. Under osmotic stress, transgenic maize held better germination ability than the unmodified Dan988 (WT) line. In addition, transgenic maize contained higher levels of antioxidant enzymes and osmotic regulatory substances compared with WT, and thus accumulated less harmful substances and this alleviated the negative effects of drought. We used the membership function method to quantify the drought tolerance and found that Dan988-BADH-4 showed the best tolerance, followed by Dan988-BADH-2 and Dan988-BADH-1 while WT ranked lowest. This was consistent with the statistical analysis of the experiments. From the indoor and field survey, we observed that the agronomic traits of transgenic maize were not affected by the overexpression of BADH. In conclusion, BADH overexpression in maize is beneficial for drought tolerance and the three transgenic maize lines can be used for further breeding experiments.

Phosphorus deficiency enhances water deficit impact on some morphological and physiological traits in four faba bean (<em>Vicia faba L.</em>) varieties

Moroccan soils, generally present low available phosphorus (P) levels which occur in almost all arid and semi-arid regions. Faba bean is one of the most significant crops in Morocco and is influenced by these constraints that affect its nutrient uptake and nitrogen fixation capacity and hence plants development. Therefore, we evaluated the response of four Vicia faba varieties - Aguadulce (Ag), Alfia (Al), Luz de Otono (LO) and Reina Mora (RM) -, grown under biological nitrogen fixation to water deficit and two phosphorus levels. The trial was conducted under greenhouse conditions and water stress was induced by keeping pots at 40% substrate field capacity (FC) versus 80% FC for the controls while phosphorus deficiency treatment consisted in the application of 25 μmol P plant−1 week−1 versus 125 μmol P plant−1 week−1 for sufficient P treatment. The results revealed a significant effect of water deficit and phosphorus deficiency either alone or combined on plants dry weights, leaf water parameters and nutrient concentrations. However sufficient phosphorus supply mitigated the adverse effects of water deficit on faba bean. We noticed significant differences between the studied varieties. Ag showed high performance concerning dry weights (1.25 g and 1.88 g plant–1 respectively for shoot and root) and high concentration of nitrogen N (4.7%) and P (0.27 mg g–1 DW) and was then qualified as the most tolerant variety to water deficit combined with P limitation. While RM was the least tolerant variety, as it showed the lowest dry weights (0.51 g and 1.4 g plant–1 respectively for shoot and root) and concentration (2.74% and 0.19 mg g–1 DW respectively for N and P). The tolerance was related to the ability to ensure efficient osmoregulation by glycine betaine accumulation, to keep leaf water balance and cell membrane stability that contribute together with adequate symbiotic nitrogen fixation to plant growth performance under combined stresses.
 Highlights - Varieties tolerant to low phosphorus and water deficiency are needed in arid and semi-arid regions with low P. - Phosphorus nutrition is advantageous for mitigating the effect of water deficit on faba bean (Vicia faba) plants and conversely, deficient P supply reduces resilience to water deficit. - The faba bean variety Aguadulce showed high tolerance to the combined effect of water deficit and phosphorus deficiency in terms of growth, leaf water potential, stomatal conductance, membrane permeability and glycine betaine accumulation. - Reina Mora was the least tolerant variety to water deficit combined with P limitation. - Combined limitation of water and phosphorus induced accumulation of glycine betaine in leaves.

Bryophytes Harbor Cultivable Actinobacteria With Plant Growth Promoting Potential.

This study was designed to investigate the cultivable actinobacteria associated with bryophytes and their plant growth promoting ability. Thirteen actinobacteria were isolated and tested for their ability to promote growth of plant in vitro and in planta. All isolates were able to produce IAA and siderophores. Six isolates were identified as members of the genus Micromonospora. Five isolates belonged to the genus Streptomyces and one each of Microbispora and Mycobacterium. Micromonospora sp. CMU55-4 was inoculated to rare moss [Physcomitrium sphaericum (C. Ludw.) Fürnr.] and could increase the amount of carotenoid, fresh weight, and dry weight of this moss. In addition, this strain promoted capsule production, and rescued P. sphaericum’s gametophytes during acclimatization to land. Strain CMU55-4 was identified as Micromonospora chalcea based on whole genome sequence analysis. Its plant growth promoting potential was further characterized through genome mining. The draft genome size was 6.6 Mb (73% GC). The genome contained 5,933 coding sequences. Functional annotation predicted encoded genes essential for siderophore production, phosphate solubilization that enable bacteria to survive under nutrient limited environment. Glycine-betaine accumulation and trehalose biosynthesis also aid plants under drought stress. M. chalcea CMU55-4 also exhibited genes for various carbohydrate metabolic pathways indicating those for efficient utilization of carbohydrates inside plant cells. Additionally, predictive genes for heat shock proteins, cold shock proteins, and oxidative stress such as glutathione biosynthesis were identified. In conclusion, our results demonstrate that bryophytes harbor plant growth promoting actinobacteria. A representative isolate, M. chalcea CMU55-4 promotes the growth of P. sphaericum moss and contains protein coding sequences related to plant growth promoting activities in its genome.

Tissue-specific modulation of metabolism and nutrients acquisition through seed priming with sodium selenate confers salt tolerance in wheat

ABSTRACT The experiment was conducted to appraise whether exogenously applied selenium (Se) could alter nutrients acquisition and metabolism to mitigate the toxic effects of salinity in wheat. Seeds of two contrasting wheat (Triticum aestivum L.) cultivars (Auqab-2000 and Seher-2006) were pre-treated with different concentrations (0, 50, 100 µM) of sodium selenate for 12 h. The pots were irrigated with different NaCl concentrations (0 and 150 mM) applied through Hoagland’s nutrient solution before sowing. Salinity reduced fresh and dry mass and grain yield, but the exogenous Se restored the growth and increased grain yield. Further, salt stress decreased the concentrations of K+, Ca2+, P, N, Fe and Se while increased the concentration of Na+ and Cl‒ in the shoots and roots of wheat. The exogenous Se increased K+, Ca2+, N, Fe and Se concentrations while decreased Na+, Cl− and P, and thus mainly reversed the inhibitory effects of salinity on nutrients uptake. Further, exogenous Se increased the accumulation of proline and glycinebetaine under salinity. Overall, Se-priming proved an effective shotgun technique to mitigate the detrimental effects of salinity possibly through its beneficial effects on tissue-specific ion acquisition and accumulation of osmoprotectants in wheat.

Glycine Betaine Accumulation, Significance and Interests for Heavy Metal Tolerance in Plants.

Unexpected biomagnifications and bioaccumulation of heavy metals (HMs) in the surrounding environment has become a predicament for all living organisms together with plants. Excessive release of HMs from industrial discharge and other anthropogenic activities has threatened sustainable agricultural practices and limited the overall profitable yield of different plants species. Heavy metals at toxic levels interact with cellular molecules, leading towards the unnecessary generation of reactive oxygen species (ROS), restricting productivity and growth of the plants. The application of various osmoprotectants is a renowned approach to mitigate the harmful effects of HMs on plants. In this review, the effective role of glycine betaine (GB) in alleviation of HM stress is summarized. Glycine betaine is very important osmoregulator, and its level varies considerably among different plants. Application of GB on plants under HMs stress successfully improves growth, photosynthesis, antioxidant enzymes activities, nutrients uptake, and minimizes excessive heavy metal uptake and oxidative stress. Moreover, GB activates the adjustment of glutathione reductase (GR), ascorbic acid (AsA) and glutathione (GSH) contents in plants under HM stress. Excessive accumulation of GB through the utilization of a genetic engineering approach can successfully enhance tolerance against stress, which is considered an important feature that needs to be investigated in depth.

Sequential expression of key genes in proline, glycine betaine and artemisinin biosynthesis of Artemisia aucheri Boiss using salicylic acid under in vitro osmotic stress

Artemisia aucheri belongs to the Asteraceae family, which is known for its medicinal and aromatic properties. The present study was conducted to elucidate the influence of salicylic acid (SA) pretreatment on proline and glycine betaine (GB) metabolism as well as artemisinin biosynthesis in A. aucheri under in vitro osmotic stress (˗0.6 MPa) induced by polyethylene glycol (PEG). The expression of ∆1-pyrroline-5-carboxylate synthetase (P5CS) and betaine aldehyde dehydrogenase (BADH) genes and related enzymes were enhanced under osmotic stress. SA pretreatment improved accumulation of proline and GB and increased the expression of BADH and P5CS enzyme activity under osmotic stress. However, proline dehydrogenase (PDH) gene expression and PDH activity were not affected by osmotic stress and SA pretreatments. In addition, SA in combination with or without PEG induced expression of the key genes involved in artemisinin biosynthesis and increased artemisinin content. These findings indicated that, higher accumulation of proline and GB under osmotic stress by SA is possibly due to increasing of osmoprotectants biosynthesis. This study suggested that A. aucheri is one of the potential species for artemisinin biosynthesis under environmental stress and exogenous SA.

Anti-stress phytohormones impact on proteome profile of green gram (Vigna radiata) under salt toxicity

Anti-stress phytohormones impact on proteome profile of green gram (Vigna radiata) under salt toxicity

Osmoregulators’ accumulation minimizes the effects of drought stress in sugarcane and contributes to the recovery of photochemical efficiency in photosystem II after rewatering

Drought is the main yield limiting factor in most sugarcane crops worldwide. This study aimed to assess the relationship between osmoregulators, photochemical efficiency of photosystem II (PSII), and regulation of electron transport rate (ETR) in sugarcane varieties under drought stress and rewatering. The experiment was conducted in pots, with two sugarcane varieties, RB72454 and RB92579. At 105 days after planting, plants were submitted to irrigation (control) and no irrigation (drought stress), followed by rewatering. The RB72454 variety was the most sensitive to drought stress, with low proline (Pro) accumulation, no change in glycine betaine (GB) concentrations, and greater electrolyte leakage (EL). High photochemical damage was also observed in PSII, including further reductions in maximum (Fv/Fm) and effective quantum efficiencies of photosystem II (ΦPSII). Drought also reduced ETR and increased non-photochemical quenching (qN), which may have contributed to delaying recovery of the RB72454 variety after rewatering. When the RB92579 variety was subjected to drought stress, it presented higher Pro and GB accumulation, lower EL and photoinhibition and small declines in Fv/Fm, ETR and ΦPSII, and slight qN increase. This resulted in less damage to the PSII photosynthetic apparatus under drought stress and contributed to maintaining cell turgidity and protecting the membrane structures of RB92579 variety chloroplasts. In addition, osmoregulators’ accumulation persisted in the RB92579 variety after rewatering, allowing for faster recovery after stress.

Exogenous Root Uptake of Glycine Betaine Mitigates Improved Tolerance to Salinity Stress in Avicenna germinans under Ambient and Elevated CO2 Conditions

In recent years, climate change has caused unpredictable variations in sea levels and an increase in atmospheric CO2 levels. Increasing temperatures and subsequent rates of evaporation have been demonstrated to cause increased coastal salinity in certain areas, which induces abiotic stress, in mangroves systems. The osmolyte, glycine betaine, has been shown in numerous studies to increase the tolerance of plants to environmental stressors, including salt stress. A handful of studies have demonstrated that increased CO2 concentrations confer increased salt tolerance and photosynthetic productivity of different mangrove species. Avicenna germinans, commonly referred to as the black mangrove, is native to Pacific and Atlantic coasts, and produces glycine betaine endogenously. This study sought to characterize the response of A. germinans exposed to increasing saline conditions, grown under normal and high CO2 concentrations. Elucidation of the role glycine betaine accumulation plays in tolerance to abiotic stress was investigated. A. germinans seedlings were subjected to increasing levels of salt stress (15–90 ppt) and treated with a dose response of glycine betaine (0–50 μM). Half of the seedlings were grown under ambient (400 ppm) CO2 conditions, and the other half were grown under elevated (800 ppm) CO2 conditions. Increased salinity tolerance and higher photosynthetic rates were observed among seedlings exposed to elevated CO2 conditions, as indicated by increased survival rates and qualitative health observations. This research may provide insights into potential consequences posed by climate change, as well as characterizing the glycine betaine signaling pathway in this mangrove species. Looking into the future, the knowledge obtained through this study may potentially contribute to our predictions of mangrove adaptability and therefore conferred protection of our coastlines in an ever‐changing world.

Nitric Oxide Stimulates Antioxidant System and Osmotic Adjustment in Soybean Under Drought Stress

The target of the present study was to determine the effect of nitric oxide (NO) on drought stress amelioration in soybean plant. Plants were treated with different polyethylene glycol (PEG) concentrations (0, 5, 10, and 15%) without or with NO (100 μM). Based on our results, drought stress significantly decreased growth in soybean plants. Increase in hydrogen peroxide, malondialdehyde, and aldehyde content indicated drought-induced oxidative stress in soybean plants. Drought stress enhanced the activities of catalase, ascorbate peroxidase, accumulation of proline and glycine betaine, and lipoxygenase activity as well as total phenol and tocopherol content. NO had a beneficial effect on drought tolerance and promoted growth in soybean plants. NO treatment maintained soybean against drought-induced oxidative hurt, thereby improving the antioxidant defense mechanism (enzymatic and non-enzymatic antioxidants). NO application caused osmotic adjustment by up-regulation accumulation of compatible solutes in stressed plants. Enhanced plant growth was linked with induction of phenylalanine ammonia-lyase and tyrosine ammonia-lyase activity and decrease in electrolyte leakage by NO application. Our results revealed that NO had ability to alleviate the destructive effects in soybean plants under drought stress.