In plants, there is a complex and multilevel network of the antioxidative system (AOS) operating to counteract harmful reactive species (RS), the foremost important of which are reactive oxygen ...species (ROS), and maintain homeostasis within the cell. Specific AOSs for plant cells are, first and foremost, enzymes of the glutathione-ascorbate cycle (Asc-GSH), followed by phenolic compounds and lipophilic antioxidants like carotenoids and tocopherols. Evidence that plant cells have excellent antioxidative defense systems is their ability to survive at H
O
concentrations incompatible with animal cell life. For the survival of stressed plants, it is of particular importance that AOS cooperate and participate in redox reactions, therefore, providing better protection and regeneration of the active reduced forms. Considering that plants abound in antioxidant compounds, and humans are not predisposed to synthesize the majority of them, new fields of research have emerged. Antioxidant potential of plant compounds has been exploited for anti-aging formulations preparation, food fortification and preservation but also in designing new therapies for diseases with oxidative stress implicated in etiology.
CRISPR-Cas systems provide bacteria with both specificity and adaptability in defence against invading genetic elements. From a theoretical perspective, CRISPR-Cas systems confer many benefits. ...However, they are observed at an unexpectedly low prevalence across the bacterial domain. While these defence systems can be gained horizontally, fitness costs may lead to selection against their carriage. Understanding the source of CRISPR-related fitness costs will help us to understand the evolutionary dynamics of CRISPR-Cas systems and their role in shaping bacterial genome evolution. Here, we review our current understanding of the potential fitness costs associated with CRISPR-Cas systems. In addition to potentially restricting the acquisition of genetic material that could confer fitness benefits, we explore five alternative biological factors that from a theoretical perspective may influence the fitness costs associated with CRISPR-Cas system carriage: (1) the repertoire of defence mechanisms a bacterium has available to it, (2) the potential for a metabolic burden, (3) larger-scale population and environmental factors, (4) the phenomenon of self-targeting spacers, and (5) alternative non-defence roles for CRISPR-Cas.
The role of endogenous hydrogen sulphide (H2S) in silicon-induced improvement in boron toxicity (BT) tolerance in pepper plants was studied. Two-week old seedlings were subjected to control ...(0.05 mM B) or 2.0 mM BT in a nutrient solution. These two treatments were combined with 2.0 mM Si. BT caused considerable reduction in biomass, chlorophyll a &b, photosystem II maximum quantum efficiency (Fv/Fm), glutathione and ascorbate in the pepper seedlings. However, it enhanced malondialdehyde (MDA) and hydrogen peroxide, electrolyte leakage, proline, H2S, and activities of catalase, superoxide dismutase, peroxidase, and L-DES. Silicon stimulated growth, proline content and activities of various antioxidant biomolecules and enzymes, leaf Ca2+, K+ and N, endogenous H2S and L-DES activity, but reduced H2O2 and MDA contents, membrane leakage and leaf B. Silicon-induced B tolerance was further enhanced by 0.2 mM NaHS, a H2S donor. A scavenger of H2S, hypotaurine (0.1 mM HT), was supplied together with Si and Si + NaHS to assess the involvement of H2S in Si-induced BT tolerance of pepper plants. Hypotaurine inverted the positive role of Si on the antioxidant defence system by reducing endogenous H2S, but NaHS supply along with Si + HT reversed the negative effects of HT, showing that H2S participated in Si-induced BT tolerance of pepper plants.
•Boron toxicity (BT) decreased plant growth and increased oxidative stress.•Silicon (Si) reversed the oxidative stress and BT-induced growth inhibition.•Si activated l-cysteine desulfhydrase (L-DES) and enhanced hydrogen sulphide (H2S).•Si enhanced antioxidants, K+ and Ca2+ contents and reduced B in the pepper plants.•H2S scavenger, hypotaurine (HT) reversed the H2S synthesis and antioxidant defence systems, and aggravated oxidative stress.
Recent advances in high-throughput technologies for omics analyses and bioinformatics for data interpretation have led to the application of omics approaches across all fields of life sciences. There ...has also been an expansion of omics research in immune studies of marine invertebrates, such as bivalves to gain insights into pathogenic infections and disease progression. Many of these omics studies have been conducted on haemocytes and haemolymph, which are the most important components of the bivalve immune system. Characterization of transcriptomes, proteomes and metabolomes of bivalve haemocytes in response to pathogenic infections and other environmental stressors have revealed valuable information regarding the mechanisms that drive the innate immune system in response to stress challenges, as well as insights regarding complex host-pathogen-environment interactions across bivalve species. For instance, detailed analysis of haemocyte transcriptomes has resulted in the discovery of a number of coding and non-coding transcripts involved in immune and stress responses. In addition, comprehensive examination of the proteome and metabolome of bivalve haemocytes following stress exposure has helped identify changes in the physiological status of the organism, including specific molecular pathways involved in these processes. Furthermore, the differently expressed molecules that have been identified through these omics studies can be used as candidate biomarkers with applications in breeding selection programs, disease diagnosis and environmental monitoring. However, despite these significant biotechnological advances, the application of omics tools for bivalve haemocyte research is currently hindered by several challenges and bottlenecks. In this contribution, we aim to review the major advances, current perspectives and future directions of three main omics (transcriptomics, proteomics and metabolomics) with regards to their application in bivalve haemocyte and aquaculture research.
•Review of omics (transcriptomics, proteomics, metabolomics) for bivalve haemocytes•Application of omics tools to investigate host-pathogen-environment interactions•Comparison of benefits and shortcomings of various omics in aquaculture research
It was aimed to examine the role of gibberellic acid (GA) induced production of hydrogen sulfide (H2S) in alleviating boron toxicity (BT) in tomato plants. Two weeks after germination, a solution ...consisting of GA (100 mg L−1) was sprayed once a week for 14 days to the leaves of cv. “SC 2121” of tomato under BT stress (BT; 2.0 mM). Before starting BT treatment, half of the seedlings were retained in a solution containing a scavenger of H2S, 0.1 mM hypotaurine (HT), for 12 h. Boron toxicity led to a substantial decrease in dry biomass, leaf water potential, leaf relative water content, chlorophyll a, chlorophyll b, photosynthetic quantum yield (Fv/Fm), ascorbate (AsA) and glutathione (GSH) in the tomato plants. However, it increased the accumulation of hydrogen peroxide (H2O2), malondialdehyde (MDA), endogenous hydrogen sulfide (H2S), and free proline as well as the activities of catalase, superoxide dismutase and peroxidase. The supplementation of GA mitigated BT by increasing the endogenous H2S, and leaf Ca2+ and K+, and reducing the contents of leaf H2O2, MDA, and B as well as membrane leakage. GA-induced BT tolerance was further enhanced by the supplementation of sodium hydrosulfide (0.2 mM NaHS), an H2S donor. A scavenger of H2S, hypotaurine (0.1 mM HT) was supplied along with the GA and NaHS treatments to assess if H2S was involved in GA-induced BT tolerance of tomato plants. Addition of HT reversed the beneficial effect of GA on oxidative stress and antioxidant defence system by reducing the endogenous H2S without changing L-DES activity, suggesting that H2S participates in GA-induced tolerance to BT of tomato plants.
•Boron toxicity (BT) led to reduced plant growth and increased oxidative stress.•Gibberellic acid (GA) increased plant growth and reversed the oxidative stress.•The GA activated hydrogen sulfide (H2S), improved antioxidant defence systems, and reduced B content in tomato plants.•Hypotaurine, HT (H2S scavenger) decreased the levels of H2S as well as hampered the antioxidant defence system.•GA and H2S both are responsible for enhancing BT tolerance of tomato plants.
The participation of nitric oxide (NO) in wheat plant tolerance to salinity stress (SS) brought about by hydrogen sulphide (H2S) via modifying the ascorbate-glutathione (AsA-GSH) cycle was studied. ...The SS-plants received either 0.2 mM sodium hydrosulfide (NaHS; H2S donor), or NaHS plus 0.1 mM sodium nitroprusside (SNP; a NO donor) through the nutrient solution. Salinity stress decreased plant growth, leaf water status, leaf K+, and glyoxalase II (gly II), while it elevated proline content, leaf Na+ content, oxidative stress, methylglyoxal (MG), glyoxalase I (gly I), the superoxide dismutase, catalase and peroxidase activities, contents of endogenous NO and H2S. The NaHS supplementation elevated plant development, decreased leaf Na+ content and oxidative stress, and altered leaf water status, leaf K+ and involved enzymes in AsA-GSH, H2S and NO levels. The SNP supplementation boosted the positive impact of NaHS on these traits in the SS-plants. Moreover, 0.1 mM cPTIO, scavenger of NO, countered the beneficial effect of NaHS by lowering NO levels. SNP and NaHS + cPTIO together restored the beneficial effects of NaHS by increasing NO content, implying that NO may have been a major factor in SS tolerance in wheat plants induced by H2S via activating enzymes connected to the AsA-GSH cycle.
•Salinity stress (SS) led to a marked reduction in plant growth and enhanced oxidative stress in wheat.•NaHS markedly eliminated the SS-induced growth inhibition and oxidative stress.•NaHS increased the intrinsic level of H2S and NO as well as induced the antioxidant defence system.•The scavenger of NO, cPTIO, inverted the effect of NaHS by decreasing NO content.•H2S and NO work together to improve SS tolerance of wheat plants.
Abstract
The shell of bivalves acts as structural support, defence against predators, stressors, and maintenance of homeostasis. Haemocytes and mantle epithelial cells participate in shell formation. ...Mantle epithelial cells produce the organic matrix of the shell and are associated with biomineralization because of their proximity to the shell surface and ability to maintain shell deposition ex vivo. Haemocytes play an immunological role and are involved in Ca2+ and CO32- intracellular transport implicated in shell mineralization. This study aims to evaluate the expression of molecules that play key roles in internal defence and the nervous system, in epithelial cells and haemocytes of the outer mantle margin of two species of bivalves, Polititapes aureus Gmelin, 1791 and Cerastoderma glaucum Bruguière, 1789, to highlight their collaborative role in shell formation. Our data show for the first time the presence of serotonin/S100 protein, and TLR2/iNOS colocalization in the haemocytes and mantle epithelial cells of P. aureus and C. glaucum, suggesting that the mantle cells perform their canonical role of sensory and biomineralizing activity, while the haemocytes perform their typical immune function, and their collaboration in shell formation, providing new information on cellular interactions in shell formation and giving more details for taxonomical studies.
C4 plants are acclimated to drought and high temperatures that are detrimental for C3 plants, and they are well equipped with a better antioxidant capacity to cope with oxidative stress caused by ...abiotic stresses. However, how C3 and C4 plants respond to oxidative stress that occurs in a specific compartment of the cell, such as chloroplast or mitochondria, is still not known. Therefore, understanding antioxidant responses of different carboxylation pathways to reactive oxygen species (ROS) at organelle level deserves an investigation. In the present study, the production of organelle originated ROS was induced with chemical agents specific to mitochondria (rotenone =ROT) and chloroplasts (methyl viologen = MV and DCMU), and antioxidant response of Flaveria robusta (C3) and F. bidentis (C4) were studied. For this purpose, activities of antioxidant system (superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX), glutathione reductases (GR)), and isoenzymes of SOD, CAT, and NADPH oxidase (NOX) activity were determined. Treatment of leaves with ROT, MV and DCMU for 4 h induced lipid peroxidation by 38%, 18% and 41% respectively in F. robusta, while 81%, 75% and 56% induction were observed for same inhibitors in F. bidentis. On the other hand, treatment with inhibitors cause decrease of CAT activity in F. robusta (27% with ROT), while increased CAT activity was observed in F. bidentis (maximum 68% with MV). Overall, the antioxidant defense responses of C3 and C4 plants were distinctive to organelle induced oxidative stress, especially in chloroplast-sourced accumulation of ROS.
•Response to organellar oxidative stress was studied in C3 and C4 species of Flaveria.•Methyl viologen, rotenone and DCMU was used to induce organellar oxidative stress.•Flaveria bidentis (C4) was more sensitive after 4 h treatment as evident by lipid peroxidation.•F. robusta (C3) CAT activity decreased, while it was increased in Flaveria bidentis (C4).•Antioxidant responses of C3 and C4 species were distinctive to organellar oxidative stress.
In the present study, the role of hydrogen sulfide (H2S) in alleviating NaCl (20 mM) induced toxicity on growth, photosynthetic pigments and photochemistry of PS II, and impact on oxidative stress ...and antioxidant systems of eggplant and tomato was studied. To confirm the role of H2S (donor sodium hydrogen sulphide (NaHS; 40 μM)) under stress, H2S scavenger; hypotaurine (HT; 200 μM) and inhibitor, propargylglycine (PAG; 100 μM) in combination with NaHS was added to the growth medium of NaCl stressed seedlings. The NaCl reduced the overall growth of the seedlings as the Na+ uptake was increased which led to removal of K+, thereby Na+/K+ homeostasis was disturbed. This condition caused severe impact on photosynthetic pigments and PS II photochemistry, thus significant decline in the values of fluorescence kinetics parameters such as Fv/Fm, FV/F0, φE0, ѱ0, PIABS except F0/FV and enhancement in energy flux parameters such as ABS/RC, TR0/RC, ET0/RC and DI0/RC was obtained. Exogenous H2S not only abolished the toxic symptoms in test seedlings but also completely alleviated the decline in growth in case of tomato seedlings. Reactive oxygen species accumulation was significantly declined in both the seedlings as evident by in vitro and in vivo analysis with the supplementation of NaHS, indicating appreciable recovery in membrane damage caused by NaCl toxicity. Antioxidative enzymes: SOD, POD, CAT and GST activities were further stimulated in response to H2S (NaHS) supplementation to the stressed seedlings, thus maintaining the redox homeostasis of cell and bringing the seedlings back to the healthy state. Moreover, the role of endogenous and exogenous H2S was also justified using the scavenger of H2S (HT; 200 μM) and inhibitor of enzymes of H2S (PAG; 100 μM). Thus, present study emphasizes the role of NaHS as H2S donor in alleviating NaCl stress in crops particularly vegetables tomato and eggplant, and may be considered as a part of important strategies to cope up with NaCl toxicity which is prevailing in natural field condition.
•Sodium chloride declined the growth and affected the growth attributes of both the studied plants.•H2S, an important gasotransmitter was found to play important role in declining the negative effect on growth of studied plants generated by NaCl.•NaCl as well as H2S regulates the endogenous H2S level in both the plants.•Role of endogenous H2S in regulating NaCl stress was justified using H2S inhibitor (propargylglycine; PAG) and scavenger (hypotaurine; HT).•H2S was found to modulate the antioxidants level keeping ROS level under control as well as enhance the photosynthetic activities of plants.
Plant biostimulants are an emerging trend of crop management products which can enhance nutrient uptake, plant growth and productivity under various abiotic stresses. The ability of diluted bee-honey ...extract (DHE) to enhance the tolerance of onion plants to salinity stress has been investigated. Two-season field experiments were consecutively conducted in 2015/16 and 2016/17 to study the effect of 25-50 g/L DHE foliar application on growth, yield, physio-biochemical attributes, and antioxidative defence of two onion cultivars (i.e. Giza
Red
and Giza-20) grown on a saline soil (EC = 8.81 dS m
‒1
). Results exhibited that DHE significantly increased biomass production, bulb yield and water use efficiency, leaf photosynthetic and pigments contents. Additionally, DHE applicati\on also improves osmoprotectants, membrane stability index (MSI) and relative water content (RWC), and enzymatic and non-enzymatic antioxidants of both onion cultivars in comparison with untreated control plants. In general, both cultivars showed a similar response to the DHE. Results of this study highlighted the potential impact of DHE as a promising plant bio-stimulant for overcoming the harmful effects of soil salinity stress by increasing the activity of plant antioxidative defence systems
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