Higher Malondialdehyde Content Research Articles

VaMYB44 transcription factor from Chinese wild Vitis amurensis negatively regulates cold tolerance in transgenic Arabidopsis thaliana and V. vinifera.

Heterologous expression of VaMYB44 gene in Arabidopsis and V. vinifera cv. 'Thompson Seedless' increases cold sensitivity, which is mediated by the interaction of VaMYC2 and VaTIFY5A with VaMYB44 MYB transcription factors play critical roles in plant stress response. However, the function of MYB44 under low temperature stress is largely unknown in grapes. Here, we isolated a VaMYB44 gene from Chinese wild Vitis amurensis acc. 'Shuangyou' (cold-resistant). The VaMYB44 is expressed in various organs and has lower expression levels in stems and young leaves. Exposure of the cold-sensitive V. vinifera cv. 'Thompson Seedless' and cold-resistant 'Shuangyou' grapevines to cold stress (-1°C) resulted in differential expression of MYB44 in leaves with the former reaching 14 folds of the latter after 3h of cold stress. Moreover, the expression of VaMYB44 was induced by exogenous ethylene, abscisic acid, and methyl jasmonate in the leaves of 'Shuangyou'. Notably, the subcellular localization assay identified VaMYB44 in the nucleus. Interestingly, heterologous expression of VaMYB44 in Arabidopsis and 'Thompson Seedless' grape increased freezing-induced damage compared to their wild-type counterparts. Accordingly, the transgenic lines had higher malondialdehyde content and electrolyte permeability, and lower activities of superoxide dismutase, peroxidase, and catalase. Moreover, the expression levels of some cold resistance-related genes decreased in transgenic lines. Protein interaction assays identified VaMYC2 and VaTIFY5A as VaMYB44 interacting proteins, and VaMYC2 could bind to the VaMYB44 promoter and promote its transcription. In conclusion, the study reveals VaMYB44 as the negative regulator of cold tolerance in transgenic Arabidopsis and transgenic grapes, and VaMYC2 and VaTIFY5A are involved in the cold sensitivity of plants by interacting with VaMYB44.

Dietary supplementation of L-carnitine relieved detrimental impacts of a high-fat diet in juvenile Trachinotus ovatus

In recent years, the dramatically high lipid level has been used in fish feeds, resulting in low survival rates of fish and huge economic losses. Based on these issues, a six-week feeding experiment was conducted to investigate whether diet supplements with L-carnitine can be used to relieve detrimental impacts on growth performance, hepatic lipid accumulation, antioxidant, anti-inflammatory and non-specific immune status, as well as intestinal morphology of Trachinotus ovatus, fed on a high-fat diet. Three isonitrogenous diets were formulated to either include or exclude high-fat and L-carnitine (lipid positive (LP): 130 g kg−1 lipid, lipid negative (LN): 210 g kg−1 lipid, lipid negative with L-carnitine (LNC): 210 g kg−1 lipid with 0.6 g kg−1L-carnitine). Results indicated that the growth performance and mid-intestine villi length of T. ovatus in the LN group were significantly lower than that of the LP group (p < 0.05), while significantly higher growth performance and better mid-intestine morphology of fish in the LNC group was found compared to the LN group (p < 0.05). mRNA expression levels of hepatic genes associated with the inflammatory and non-specific immune statue of T. ovatus in the LN group were significantly higher compared with the LP group (p < 0.05), while that of the LNC group was significantly lower compared with the LN group (p < 0.05). Hepatic triglyceride content and lipid droplets in the LN group were significantly elevated, compared with the LP group (p < 0.05). On the contrary, diet supplemented with L-carnitine could mitigate hepatic lipid accumulation in fish caused by a high-fat diet. Regarding antioxidant states, higher malondialdehyde content in the LN group (p > 0.05) and significantly higher levels in the LNC group (p < 0.05) were found, compared with the LP group, while no statistical difference was found between the LN and LNC groups (p > 0.05). In conclusion, L-carnitine can relieve the detrimental impact on growth performance of T. ovatus exposed to a high-fat diet treatment by reducing hepatic lipid accumulation and improving intestinal morphology, anti-inflammatory and non-specific immune status, but could not mitigate oxidative pressure.

Exogenous calcium application enhances salt tolerance of sweet sorghum seedlings

AbstractThe intensification of global soil salinization has seriously decreased crop yield. At the same time, the rapid increase in population has raised the demand for crop yields. Reasonable use of saline‐alkali land and cultivation of salt‐tolerant crops through transgenic technology becomes more important. Sweet sorghum [Sorghum bicolor (L.)], as an important energy crop, resists abiotic stress effectively. In our previous salt tolerance gene‐screening experiment of sweet sorghum, it was found that applying calcium ions could alleviate salt stress of sweet sorghum to some extent. Therefore, 10 and 20 mM CaCl2 were applied to explore the effect of exogenous calcium application on salt stress. Compared with the sweet sorghum treated by salt stress, the dry and fresh weight of the plants were significantly increased, and the content of malondialdehyde (MDA) was decreased after applying calcium ions. At the same time, diaminobenzidine and nitro blue tetrazolium chloride monohydrate staining results showed that the contents of H2O2 and O2−• in the plants after calcium application were lower than those only treated with salt stress. To investigate the regulation mechanism of exogenous calcium application alleviating salt stress, RNA‐seq analysis was performed using libraries established in Roma roots under normal and NaCl treatment. Combined with Gene Ontology and Kyoto Encyclopaedia of Genes and Genomes analysis, we found that calcium‐related genes were more involved in the oxidation‐reduction process and carbohydrate metabolism pathway. Among all differentially expressed genes, 12 known functional genes were further explored based on functional annotations and existing studies. To detect whether these 12 genes are related to salt response, we treated the Arabidopsis mutants of their homologous genes with 150 mM NaCl for 7 days. Among them, atglr3.5, atgad4, atiqm4, atglr2.8 and annat7 showed worse growth, lower survival rate and higher MDA content than WT under salt stress. This indicates that applying exogenous calcium can affect the expression of SbGR3.4, SbGADX1, SbIQM4, SbGR2.8 and SbAnnD7, which can regulate the expression of genes related to the lignin degradation, absorption of NH4+, and ubiquitination‐proteasome pathway, energy metabolism and cleaning of ROS accumulation in sweet sorghum under salt stress, so as to enhance the salt tolerance of plants.

Maize Seed Germination Under Low-Temperature Stress Impacts Seedling Growth Under Normal Temperature by Modulating Photosynthesis and Antioxidant Metabolism.

Spring maize is usually subjected to low-temperature stress during seed germination, which retards seedling growth later even under a suitable temperature. However, the mechanism underlying maize seed germination under low-temperature stress impacting seedling growth is still ambiguous. In this study, we used one low-temperature sensitive maize (SM) and one low-temperature resistance maize (RM) to investigate the mechanism. The results showed that the SM line had higher malondialdehyde content and lower total antioxidant capacity (TAC) and germination percentage than the RM line under low-temperature stress, indicating the vulnerability of SM line to low-temperature stress. Further transcriptome analysis revealed that seed germination under low-temperature stress caused the down-regulation of photosynthesis-related gene ontology terms in two lines. Moreover, the SM line displayed down-regulation of ribosome and superoxide dismutase (SOD) related genes, whereas genes involved in SOD and vitamin B6 were up-regulated in the RM line. Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed that photosynthesis and antioxidant metabolism-related pathways played essential roles in response to low-temperature stress during seed germination. The photosynthetic system displayed a higher degree of damage in the SM line. Both qRT-PCR and physiological characteristics experiments showed similar results with transcriptome data. Taken together, we propose a model for maize seed germination in response to low-temperature stress.

Potassium (K+) Starvation-Induced Oxidative Stress Triggers a General Boost of Antioxidant and NADPH-Generating Systems in the Halophyte Cakile maritima.

Potassium (K+) is an essential macro-element for plant growth and development given its implication in major processes such as photosynthesis, osmoregulation, protein synthesis, and enzyme function. Using 30-day-old Cakile maritima plants as halophyte model grown under K+ deprivation for 15 days, it was analyzed at the biochemical level to determine the metabolism of reactive oxygen species (ROS), key photorespiratory enzymes, and the main NADPH-generating systems. K+ starvation-induced oxidative stress was noticed by high malondialdehyde (MDA) content associated with an increase of superoxide radical (O2•−) in leaves from K+-deficient plants. K+ shortage led to an overall increase in the activity of hydroxypyruvate reductase (HPR) and glycolate oxidase (GOX), as well as of antioxidant enzymes catalase (CAT), those of the ascorbate-glutathione cycle, peroxidase (POX), and superoxide dismutase (SOD), and the main enzymes involved in the NADPH generation in both leaves and roots. Especially remarkable was the induction of up to seven CuZn-SOD isozymes in leaves due to K+ deficiency. As a whole, data show that the K+ starvation has associated oxidative stress that boosts a biochemical response leading to a general increase of the antioxidant and NADPH-generating systems that allow the survival of the halophyte Cakile maritima.

Regulatory role of myo-inositol in vegetable oil-mediated lipid metabolism and health of Chinese mitten crab (Eriocheir sinensis)

Vegetable oils (VOs) are widely used in the aquatic feed industry because of their stable source and low price, but they can cause a series of adverse effects on aquatic animals. Myo-inositol (MI) plays a vital role in regulating lipid metabolism and the health of aquatic animals. However, it remains unclear whether MI has a regulatory role on the utilization of different VOs. An 8-week study was conducted to investigate the effects of MI on the growth, lipid metabolism, and health of the Chinese mitten crab under four oil sources, including palm oil (PO), olive oil (OO), safflower oil (SO), and perilla oil (PFO) in diets. The highest growth performance and the lowest lipid levels in the whole body, hepatopancreas and muscle were observed in crabs fed the PFO diet without MI supplementation. Dietary MI markedly reduced the lipid deposition in the hepatopancreas when crabs were fed the PO and OO diets. Moreover, dietary MI increased the expression of genes related to the uptake and β-oxidation of fatty acid when crabs were fed the PO and OO diets. A high correlation was observed between dietary fatty acid composition and fatty acid composition in the hepatopancreas and muscle. The highest malondialdehyde content was observed in the PFO group. Dietary MI could decrease malondialdehyde content in the hepatopancreas when crabs were fed the PO and PFO diets. However, the lowest inflammation-related genes expression was observed in crabs fed the PFO diet without MI supplementation. Dietary MI could decrease the mRNA levels of these genes when crabs were fed the PO and OO diets. This study indicates that MI is a functional nutrient to improve the low lipid utilization and inflammatory responses caused by dietary palm oil and olive oil in E. sinensis.

Silicon Fertigation Regimes Attenuates Cadmium Toxicity and Phytoremediation Potential in Two Maize (Zea mays L.) Cultivars by Minimizing Its Uptake and Oxidative Stress

Silicon (Si) is an important plant-derived metabolite that is significantly involved in maintaining the stability of a plant’s metabiological, structural and physiological characteristics under the abiotic stressed environment. We conducted the present study using maize (Zea mays L.) cultivars (Sadaf and EV-20) grown in sand artificially contaminated with cadmium (500 µM) in Hoagland’s nutrient solution to investigate its efficiency. Results from the present study evidenced that the toxic concentration of Cd in sand significantly reduced shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight and root dry weight by 88, 94, 89, 86 99 and 99%, respectively, in Sadaf while decreasing by 98, 97, 93, 99, 84 and 91%, respectively, in EV-20. Similarly, Cd toxicity decreased total chlorophyll and carotenoid content in both varieties of Z. mays. Moreover, the activities of various antioxidants (superoxidase dismutase, peroxidase and catalase) increased under the toxic concentration of Cd in sand which was manifested by the presence of membrane permeability, malondialdehyde (MDA), and hydrogen peroxide (H2O2). Results additionally showed that the toxic effect of Cd was more severe in EV-20 compared with Sadaf under the same conditions of environmental stresses. In addition, the increased concentration of Cd in sand induced a significantly increased Cd accumulation in the roots (141 and 169 mg kg−1 in Sadaf and EV-20, respectively), and shoots (101 and 141 mg kg−1 in Sadaf and EV-20, respectively), while; EV-20 accumulated higher amounts of Cd than Sadaf, with the values for both bioaccumulation factor (BAF) and translocation factor (TF) among all treatments being less than 1. The subsequent negative results of Cd injury can be overcome by the foliar application of Si which not only increased plant growth and biomass, but also decreased oxidative damage induced by the higher concentrations of MDA and H2O2 under a Cd-stressed environment. Moreover, external application of Si decreased the concentration of Cd in the roots and shoots of plants, therefore suggesting that the application of Si can ameliorate Cd toxicity in Z. mays cultivars and results in improved plant growth and composition under Cd stress by minimizing oxidative damage to membrane-bound organelles.

Taurine Ameliorates Oxidative Stress in Spinal Cords of Diabetic Rats via Keap1-Nrf2 Signaling.

Hyperglycemia associated with diabetes mellitus (DM) causes oxidative stress, which is involved in the onset and development of diabetic neuropathy. Taurine, a powerful antioxidant, is an effective inhibitor of oxidative stress. The present experiment was conducted to explore the effect of taurine treatment on alterations in body weight, blood glucose, oxidative stress, and Keap1-Nrf2 signaling in the spinal cords of DM rats. The DM rat model was established by STZ injection, and taurine was administered in the drinking water. Body weight and blood glucose were recorded during the experiment. The expression of Gap-43 and MBP proteins was examined by Western blot. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were examined as indicators of oxidative stress. The expression of Keap1, Nrf2, and HO-1 gene was examined by real-time PCR. The results showed that compared with the control group, the body weight was decreased, blood glucose was increased, and both Gap-43 and MBP expression were decreased in DM rats, which were all remarkably reversed by taurine treatment. Oxidative stress, as reflected by lower SOD activity and higher MDA concentration, was inhibited in taurine-treated DM rats. Supplemental taurine also downregulated the mRNA level of Keap1, while upregulating Nrf2 and HO-1 mRNA levels. These results showed that taurine inhibits oxidative stress in the spinal cords of DM rats, an effect that might involve the regulation of Keap1-Nrf2 signaling.

Nitroxin bio-fertilizer improves growth parameters, physiological and biochemical attributes of cantaloupe (Cucumis melo L.) under water stress conditions

Abstract Effect of chemical- and bio-fertilizers (Nitroxin) on growth parameters, physiological and biochemical attributes, and yield of cantaloupe (Cucumis melo L.) under water stress conditions has been studied. Irrigation was done at 3 levels including 50, 75, and 100% of the water requirement of the cantaloupe plant. Water stress had an adverse effect on plant growth and the application of 120 kg ha−1 chemical fertilizer with Nitroxin in 100% water requirement had the highest growth parameters including fruit weight (1.84 kg) and fruit length (20.71 cm). The highest Malondialdehyde content was observed at 60 kg ha−1 of chemical fertilizer using Nitroxin. Application of Nitroxin had a significant effect on electrolyte leakage, proline content, relative water content, colour, vitamin C, titratable acidity, firmness, and total soluble solids (TSS) during water stress. The highest content of total chlorophyll (5.81 mg g−1 fresh weight) was observed at 100% field capacity with 180 kg ha−1 of chemical fertilizer with Nitroxin. The total phenol content of fruit enhanced by increasing drought stress and a significant difference was observed by application of biological and chemical fertilizers compared to control. Antioxidant enzyme activity including ascorbate peroxidase, catalase, superoxide dismutase and peroxidase increased during water stress and the application of chemical fertilizer with Nitroxin enhanced antioxidant enzyme activity during stress. Overall, the application of chemical fertilizers and Nitroxin improved growth parameters, physiological and biochemical attributes and yield of cantaloupe plants during water stress.

Maternal exposure to silicon dioxide nanoparticles reduces hippocampal neurogenesis and synaptogenesis and induces neurodegeneration in rat offspring hippocampus.

Silicon dioxide nanoparticles (SiO2-NPs) are among the most widely used nanoparticles because of their chemical-physical properties. Since most brain maturation occurs in the neonatal period in humans and many mammals, it is important to understand how NPs may affect this process. This study tested the hypothesis that SiO2-NPs from treated dams could affect the hippocampus of neonatal rats during lactation. Twenty-four pregnant rats, after delivery, were divided into three groups of control, SiO2-NPs (25mg/kg) and SiO2-NPs (100mg/kg). The rats were treated from 2nd to 21st days post-delivery by gavage and the effects of these NPs were evaluated in the offspring's hippocampi to reveal the effects of maternal exposure to SiO2-NPs during lactation on the offspring's hippocampi. The offspring in the SiO2-NPs groups had higher malondialdehyde concentration and lower antioxidant activity in the hippocampi than the non-treated control group. The mean number of doublecortin positive (DCX+) cells and synaptophysin expression in the hippocampi of the SiO2-NPs groups were significantly lower than the control group, whereas the mean number of dark neurons was significantly higher. Also, animals in the SiO2-NPs groups had a weak cognitive performance in adulthood. In conclusion, maternal exposure to SiO2-NPs via breastfeeding could affect offspring's hippocampal neurogenesis and synaptogenesis, leading to impaired cognitive performance.

Spermogram and Hormone Profile Indicators Analysis Among Patients with Different Types of Male Infertility Depending on Antioxidant System Status

The objective: evaluation of interrelation between indicators of spermoplasm, androgen profile and malondialdehyde (MDA) content in spermoplasm among men with different types of male infertility. Materials and methods. 39 men at the age ranged from 24 to 45 years with different degrees of spermatogenesis and hormonal profile disorders were examined; MDA content in spermoplasm among patients who were diagnosed with «secretory male infertility» (n=7) was 23.3-38.3 μm/l, diagnosed with «excretory-toxic male infertility» (n=32) – 17.3–53.0 μm/l, therefore this group was divided into subgroups: 1 – up to 19.9 μm/l; 2 – within 20.6–29.1 mcm/l; 3 – more than 30.0 μm/l. In spermoplasm of the control group (donor sperm), this indicator was within 20.8–24.9 μm/l range. Interrelation assessment between the investigated indicators was carried out by methods of variational and correlation analysis using non-parametric statistics. Results. Studies results showed that the number of white blood cells in patients’ sperm of all groups exceeded the standard, wherein a close connection between this indicator and MDA content in spermoplasm (r=0.99 and r=0.48, with α≤0,05) was established. In groups where lipid peroxidation activity was significantly higher than control indicators, the highest percentage of men (more than 40%) with reduced sperm activity and viability was detected. Free testosterone decrease was observed among almost 70-90% of examined men, while the most significant changes were found among patients who were diagnosed with «excretory-toxic male infertility» and high MDA content in spermoplasm. A close positive connection between MDA content and sperm dilution time (r=0.79; α≤0,05) was established in group of patients who were diagnosed with «secretory male infertility», as well as the level of LH in blood (r=0.74; α≤0,05); among patients who were diagnosed with «excretory-toxic male infertility» the status of the pro-antioxidant system, which is characterized as «oxidative stress» (third subgroup), a reliable negative association was found between MDA level in spermoplasm and the level of FSH in blood (r=– 0.75; α≤0,05). Conclusions. A relation between high MDA level in spermoplasm and increase of white blood cells number in sperm was established, as well as a decrease of sperm motor activity and content of bioavailable testosterone in blood.

Influence of Stocking Density on Growth Performance, Intestinal Antioxidant Status, and Immune‐Related Gene Expression of Endangered Megalobrama pellegrini Reared in a Flow‐Through System

AbstractA 42‐d feeding trial was conducted to evaluate the effects of stocking density on the growth and health status of juvenile Megalobrama pellegrini. Fish (initial body weight = 0.45 ± 0.01 g) were reared in a flow‐through system under five stocking densities: 0.15, 0.24, 0.34, 0.42, and 0.50 kg/m3. Significantly lower growth performance (weight gain and specific growth rate) and a higher feed conversion ratio were recorded in fish reared at the highest stocking density (0.50 kg/m3). Similarly, intestinal oxidative stress analyses indicated that activities of the antioxidant enzymes superoxide dismutase and catalase were reduced in M. pellegrini reared at the highest stocking density; the highest malondialdehyde content was also recorded in this group. In addition, intestinal glutathione content was significantly increased in higher‐density groups compared with the lowest density group (0.15 kg/m3), and the highest value appeared in the 0.34‐kg/m3 group. Intestinal CYP1A* (cytochrome P450 family 1 subfamily A gene) expression was significantly lower in the 0.15‐kg/m3 group than in the 0.42‐kg/m3 group. Furthermore, the 0.50‐kg/m3 group had significantly higher gene expression of Nrf2* (nuclear factor [erythroid‐derived 2]‐like 2), NF‐κB* (nuclear factor kappa beta), and MyD88* (myeloid differentiation factor 88) than the lower‐density groups. This study indicated that 0.45–1.36‐g M. pellegrini could be cultured at a density of 0.34 kg/m3 for maximum growth in a flow‐through system without negative effects on the measured physiological indicators of stress and immunity.

A tau class glutathione-S-transferase (OsGSTU5) confers tolerance against arsenic toxicity in rice by accumulating more arsenic in root

Arsenic (As) considered as one of the hazardous metalloid that hampers various physiological activities in rice. To study the mechanism of As tolerance in rice, one differentially expressed tau class glutathione-S-transferase (OsGSTU5) has been selected and transgenic rice plants with knockdown (KD) and overexpressing (OE) OsGSTU5 were generated. Our results suggested that KD lines became less tolerant to As stress than WT plants, while OE lines showed enhanced tolerance to As. Under As toxicity, OE and KD lines showed enhanced and reduced antioxidant activities such as, SOD, PRX and catalase, respectively indicating its role in ROS homeostasis. In addition, higher malondialdehyde content, poor photosynthetic parameters and higher reactive oxygen species (ROS) in KD plant, suggests that knockdown of OsGSTU5 renders KD plants more susceptible to oxidative damage. Also, the relative expression profile of various transporters such as OsABCC1 (As sequestration), Lsi2 and Lsi6 (As translocaters) and GSH dependent activity of GSTU5 suggests that GSTU5 might help in chelation of As with GSH and sequester it into the root vacuole using OsABCC1 transporter and thus limits the upward translocation of As towards shoot. This study suggests the importance of GSTU5 as a good target to improve the As tolerance in rice

Processing Characteristics of Freeze-Dried Pork Powder for Meat Emulsion Gel.

The processing characteristics of freeze-dried pork powder as raw meat for comminuted meat products were compared with those of freeze-thawed pork. The tertiary structural properties, oxidation, and solubility of proteins in the freeze-dried pork powder were investigated. In addition, the properties of the emulsion gels manufactured with freeze-dried pork powder (GFD) and freeze-thawed pork (GFT) at 1.5% and 2.0% NaCl were evaluated. The surface hydrophobicity and intrinsic tryptophan fluorescence intensity of myofibrillar proteins between the freeze-dried pork powder and freeze-thawed pork were similar. However, freeze-dried pork powder had higher carbonyl compounds and lower solubility of sarcoplasmic and myofibrillar proteins than freeze-thawed pork (p<0.05). GFD had higher cooking loss than GFT in 2.0% NaCl, and lower hardness and a* value of GFD were observed regardless of NaCl level (p<0.05). Moreover, GFD had higher malondialdehyde content than GFT at the two NaCl concentrations (p<0.05). Therefore, our study demonstrated that freeze-dried pork powder has lower functional properties than freeze-thawed pork as raw meat for comminuted meat products.

Comparative Transcriptomics for Pepper (Capsicum annuum L.) under Cold Stress and after Rewarming

Cold stress has become one of the main abiotic stresses in pepper, which severely limits the growth and development of pepper. In this study, the physiological indicators and transcriptome of a cold-tolerance (CT) inbred line A188 and a cold-sensitive (CS) inbred line A122 under cold–rewarm treatments were studied; the aim of this study was to determine the potential of the key factors in pepper response to cold stress. Compared with CT, CS wilts more seriously after cold stress, with poor resilience, higher content of malondialdehyde, and lower content of soluble sugar and total chlorophyll. Moreover, during cold treatment, 7333 and 5953 differentially expressed genes (DEGs) were observed for CT and CS, respectively. These DEGs were significantly enriched in pathways related to photosynthesis, plant hormone signal transduction, and DNA damage repair. Interestingly, in addition to the widely studied transcription factors related to cold, it was also found that 13 NAC transcription factors increased significantly in the T4 group; meanwhile, the NAC8 (Capana02g003557) and NAC72 (Capana07g002219) in CT were significantly higher than those in CS under rewarming for 1 h after 72 h cold treatment. Notably, weighted gene coexpression network analysis identified four positively correlated modules and eight hub genes, including zinc finger proteins, heat shock 70 kda protein, and cytochrome P450 family, which are related to cold tolerance. All of these pathways and genes may be responsible for the response to cold and even the cold tolerance in pepper.

Knockdown of 60S ribosomal protein L14-2 reveals their potential regulatory roles to enhance drought and salt tolerance in cotton

BackgroundCotton is a valuable economic crop and the main significant source of natural fiber for textile industries globally. The effects of drought and salt stress pose a challenge to strong fiber and large-scale production due to the ever-changing climatic conditions. However, plants have evolved a number of survival strategies, among them is the induction of various stress-responsive genes such as the ribosomal protein large (RPL) gene. The RPL gene families encode critical proteins, which alleviate the effects of drought and salt stress in plants. In this study, comprehensive and functional analysis of the cotton RPL genes was carried out under drought and salt stresses.ResultsBased on the genome-wide evaluation, 26, 8, and 5 proteins containing the RPL14B domain were identified in Gossypium hirsutum, G. raimondii, and G. arboreum, respectively. Furthermore, through bioinformatics analysis, key cis-regulatory elements related to RPL14B genes were discovered. The Myb binding sites (MBS), abscisic acid-responsive element (ABRE), CAAT-box, TATA box, TGACG-motif, and CGTCA-motif responsive to methyl jasmonate, as well as the TCA-motif responsive to salicylic acid, were identified. Expression analysis revealed a key gene, Gh_D01G0234 (RPL14B), with significantly higher induction levels was further evaluated through a reverse genetic approach. The knockdown of Gh_D01G0234 (RPL14B) significantly affected the performance of cotton seedlings under drought/salt stress conditions, as evidenced by a substantial reduction in various morphological and physiological traits. Moreover, the level of the antioxidant enzyme was significantly reduced in VIGS-plants, while oxidant enzyme levels increased significantly, as demonstrated by the higher malondialdehyde concentration level.ConclusionThe results revealed the potential role of the RPL14B gene in promoting the induction of antioxidant enzymes, which are key in oxidizing the various oxidants. The key pathways need to be investigated and even as we exploit these genes in the developing of more stress-resilient cotton germplasms.

Physiological responses of young oil palm (Elaeis guineensis Jacq.) plants to repetitive water deficit events

Stomatal and non-stomatal limitations to photosynthesis and acclimation of the photosynthetic machinery to repetitive water deficit (WD) events were investigated in oil palms (Elaeis guineensis Jacq.). For this, well-watered plants (control treatment) were compared with plants subjected to one, two, and three WD events imposed by withholding irrigation until their predawn leaf water potential (Ψpd) reached around −2.5 MPa. Treatment comparisons were performed over 28 days. The Ψpd decreased equally between WD treatments. Decreases in net CO2 assimilation rate (A) were similar between stressed plants until day 7. In the following days, the A was higher in plants thrice stressed than in those stressed once. Stomatal conductance decreased similarly between WD treatments, but mesophyll conductance to CO2 was lower in plants subjected to a single WD. Chloroplast CO2 concentration decreased similarly between plants subjected to one and three WD events until day 14, but it was lower in the former on subsequent days. Plants subjected to a single WD event showed lower Ribulose 1,5 bisphosphate carboxylase/oxygenase (Rubisco) activity, maximum rate of electron transport (Jmax), and higher rates of photorespiration and dark respiration than other treatments. Plants subjected to one WD event also showed lower maximum quantum efficiency of photosystem II (PSII) photochemistry and PSII maximum efficiency concomitantly with higher malondialdehyde content. The results support that repetitive WD events induce the acclimation of the photosynthetic machinery in oil palm through adjustments in carboxylase Rubisco activity, Jmax, photorespiration, and respiration rates, as well as attenuating oxidative damages to PSII and membrane lipids.

Effect of New Pre-Emergence Herbicides on Quality and Yield of Potato and Its Associated Weeds

Potato is an economically important vegetable crop in Egypt. Weed infestation, especially broad-leafed, during the vegetative growth stage substantially affects both crop yield and tuber quality. In the current study, the impact of new ready-mix pre-emergent herbicides on broadleaf weeds, tuber yield, and quality was evaluated. The two-year field experiment comprised the following treatments: (1) Un-weeded control, (2) Hand hoeing, (3) Sencor, (4) Ecopart, (5) Zeus, (6) Kroki, and (7) Flomex. The results showed that weed control treatments significantly reduced the weed density compared to un-weeded control and the herbicides efficacy reached over 90%. The herbicidal treatments also significantly increased the activity of antioxidant enzymes peroxidases (POX) and catalase (CAT) and improved the non-enzymatic antioxidant (carotenoids) compared to un-weeded control. Conversely, the higher content of malondialdehyde (MDA) in potato leaves was obtained for un-weeded control. Moreover, weed control treatments caused significant enhancement in plant growth parameters, yield, and its components in addition to tuber quality of potato. Compared to the un-weeded control, maximum tuber yield was observed in Flomex followed by Ecopart, Kroki, Zeus, and Sencor, respectively. The higher number of tubers and total yield were recorded in plants treated with Flomex plus compared to all the other treatments. Higher content of total soluble sugar, total soluble protein, and total starch content was observed in weed control treatments compared with un-weeded control. Based on Pearson’s correlation and heatmap analysis, the changes in agro-physiological parameters data are linked to the herbicidal treatments. The results indicate that the applied herbicides could be alternative products for Sencor and an option for controlling broadleaved weeds. However, further studies are needed to ensure their efficacy and safety under other conditions.

The cotton 70-kDa heat shock protein GhHSP70-26 plays a positive role in the drought stress response

The 70-kDa heat shock protein (HSP70) is a molecular chaperone that plays an important role in the response of plants to abiotic stress, but the function and molecular mechanism of HSP70 in the cotton drought stress response are unclear. In this study, the HSP70-encoding gene GhHSP70-26, which belongs to the cytoplasmic HSP70 subgroup, was cloned from upland cotton (Gossypium hirsutum L.). The transcript level of GhHSP70-26 in cotton leaves was higher than that in cotton stems and roots. GhHSP70-26 was found to respond at the transcriptional level to polyethylene glycol (PEG) and abscisic acid (ABA) treatment and to cold, salt, and heat stress, and its transcript level was positively correlated with the drought resistance of different cotton varieties. Heterologous overexpression of the GhHSP70-26 gene improved the drought resistance of transgenic tobacco compared with that of wild-type (WT) tobacco, and the transgenic tobacco plants were characterized by low leaf wilting, high survival, low leaf water loss, increased root length and high chlorophyll content. Moreover, the transgenic tobacco plants overexpressing GhHSP70-26 had higher proline contents, higher superoxide dismutase (SOD) and peroxidase (POD) enzyme activities, and lower malondialdehyde (MDA) and reactive oxygen species (ROS) contents than the WT tobacco plants. The transcript levels of the stress response-related genes NtLEA, NtERD10D, NtPOD, NtSOD, and NtNCED3-1 in transgenic tobacco overexpressing GhHSP70-26 were significantly higher than those in WT tobacco. In contrast, under drought stress, unlike the results obtained with the pTRV2 empty vector (EV)-transformed and WT cotton plants, the use of virus-induced gene silencing (VIGS) technology to silence the GhHSP70-26 gene in cotton resulted in plants with severely wilted leaves, an increased water loss rate, a higher MDA content, and higher relative electrical conductivity (REC). Furthermore, yeast one-hybrid assays showed that GhbZIP43 and GhHSF8 bind to ABA-responsive elements (ABREs) and heat shock elements (HSEs) in the GhHSP70-26 promoter, respectively. Moreover, yeast two-hybrid, bimolecular fluorescence complementation and luciferase complementation assays showed that the GhHSP70-26 protein interacts with the ascorbate peroxidase (APX) GhAPX2 protein. These results indicate that by reducing the degrees of cell membrane damage and cellular damage caused by ROS stress, the GhHSP70-26 protein plays a positive role in the response of plants to drought stress.

Proline metabolism and biosynthesis behave differently in response to boron-deficiency and toxicity in Brassica napus

Proline biosynthesis and accumulation is a common response to unfavorable environment in many plants. This work aimed to elucidate the effects of boron (B)-deficiency and toxicity on proline metabolism and biosynthesis in Brassica napus in a hydroponic experiment. The results showed that B-deficiency and toxicity exert injurious impact on plant growth, accumulated high malondialdehyde (MDA) content, and caused the destruction of subcellular structure. Proline accumulated in both B deprivation and B toxicity plants, except B toxicity-treated root. In roots, B-deficiency increased ornithine content and pyrroline-5-carboxylate reductase (P5CR) activity, with the higher expression of BnaC03.P5CR, whilst decreased glutamate, glutamate-1-semialdehyde (GSA), pyrroline-5-carboxylate (P5C) contents and ornithine-δ-aminotransferase (δ-OAT), pyrroline-5-carboxylate synthetase (P5CS), proline dehydrogenase (ProDH) activities in terms of down-regulated the BnaC04.P5CS2, BnaA04.P5CS2, and BnaAnn.ProDH expression. The glutamate and GSA contents were decreased while P5C, arginine, and ornithine contents were enhanced in leaves under B-deficient and toxicity conditions. Lower glutamate pathway-related substance contents, P5CR, and δ-OAT activities while higher ProDH activity along with the same trend of related-gene expression were observed in B-toxicity-treated roots. Importantly, principal component analysis (PCA) in conjunction with correlation analysis indicated that ornithine pathway-related substances and enzymes contributed more to proline accumulation in B-deficient plant and B toxicity-treated leaves. Collectively, proline accumulation is caused by increased synthesis and decreased decomposition, and positively contributed, at least partly, by regulated ornithine pathway.