mM Of NaCl Research Articles

Preparation and in vitro degradation behavior of biodegradable porous Zn-Li-Ca alloy bone repair scaffolds

Porous pure Zn alloy scaffolds are often used for bone defects, but their clinical effects are limited due to poor mechanical properties and uneven degradation. In this study, porous Zn-Li-Ca alloy scaffolds with 70 % porosity were prepared by pressure infiltration method with 450–600 μm NaCl particles were used as pore-making agent. The effect of pore structure and the content of Ca element on, mechanical properties, degradation and weight loss of porous Zn alloy scaffolds soaked in simulated body fluids (SBF) for 4 weeks were studied. The results showed that the Zn alloy scaffolds prepared by spherical sodium chloride has high pore connectivity, and the yield strength and elastic modulus of Zn-0.8Li-0.8Ca reach 35.80 ± 1.89 MPa and 2.45 ± 0.19 GPa, respectively. Compared with the pure Zn alloy scaffolds, the yield strength was increased by 18.5 times, the elastic modulus was increased by 9 times, which meets the mechanical requirements of human cancellous bone. Compared with Zn-0.8Li alloy scaffolds, the weight loss rate and degradation rate at 4 weeks reached 7.51 % and 0.21 mm/y, respectively. In vitro studies showed that the addition of Ca element weakened the formation of Li2CO3 protective layer and accelerated the degradation rate of the scaffold. The problem of slow degradation rate of Zn-Li alloy was solved, which laid a foundation for subsequent in vivo implantation experiments. The results of this study indicate that the porous biodegradable Zn-based scaffold has great application potential in bone defects.

Research on topological effect of natural small molecule and high–performance antibacterial air filtration application by electrospinning

The application of natural small molecule (NSM) in electrospun fibers is the key to achieving powerful functionality and sustainable development. However, the lack of understanding regarding the mechanism for loading NSM hinders the advancement of high–performance functional fibers. This work clarified the loading mechanism of NSM in polymer solution by comparing the different behaviors of curcumin (Cur), phloretin (PL), and tea polyphenols (TP) blended ethyl cellulose (EC) solutions. We found that TP may lead to the folding of polymer chains due to its strongest hydrogen bond, which in turn promoted the dispersion of TP along the polymer chain. Therefore, TP could achieve good electrospinnability at the highest loading capacity (16 times the Cur and 4 times the PL). Finally, chitosan was introduced into EC/TP to prepare tree–like nanofibers, achieving high–performance antibacterial air filtration. The filtration efficiency for 0.3 μm NaCl particles, pressure drop, and quality factor were 99.991 %, 85.5 Pa, and 0.1089 Pa−1, respectively. The bacteriostatic rates against Escherichia coli and Staphylococcus aureus were all 99.99 %. This work will promote the application of NSM and the developments of multifunctional electrospun fibers and high–performance air filters.

Deciphering the regulatory networks involved in mild and severe salt stress responses in the roots of wild grapevine Vitis vinifera spp. sylvestris.

Transcriptional regulatory networks are pivotal components of plant's response to salt stress. However, plant adaptation strategies varied as a function of stress intensity, which is mainly modulated by climate change. Here, we determined the gene regulatory networks based on transcription factor (TF) TF_gene co-expression, using two transcriptomic data sets generated from the salt-tolerant "Tebaba" roots either treated with 50mM NaCl (mild stress) or 150mM NaCl (severe stress). The analysis of these regulatory networks identified specific TFs as key regulatory hubs as evidenced by their multiple interactions with different target genes related to stress response. Indeed, under mild stress, NAC and bHLH TFs were identified as central hubs regulating nitrogen storage process. Moreover, HSF TFs were revealed as a regulatory hub regulating various aspects of cellular metabolism including flavonoid biosynthesis, protein processing, phenylpropanoid metabolism, galactose metabolism, and heat shock proteins. These processes are essentially linked to short-term acclimatization under mild salt stress. This was further consolidated by the protein-protein interaction (PPI) network analysis showing structural and plant growth adjustment. Conversely, under severe salt stress, dramatic metabolic changes were observed leading to novel TF members including MYB family as regulatory hubs controlling isoflavonoid biosynthesis, oxidative stress response, abscisic acid signaling pathway, and proteolysis. The PPI network analysis also revealed deeper stress defense changes aiming to restore plant metabolic homeostasis when facing severe salt stress. Overall, both the gene co-expression and PPI network provided valuable insights on key transcription factor hubs that can be employed as candidates for future genetic crop engineering programs.

Ethyl cellulose/gelatin/β–cyclodextrin/curcumin nanofibrous membrane with antibacterial and formaldehyde adsorbable capabilities for lightweight and high–performance air filtration

Functionalization of bio–based nanofibers is the development tendency of high–performance air filter. However, the conventional structural optimization strategy based on high solution conductivity greatly hinders the development of fully bio–based air filter, and not conducive to sustainable development. This work fabricated fully bio–based nanofibrous membrane with formaldehyde–adsorbable and antibacterial capabilities by electrospinning low–conductivity solution for high–performance air filtration and applied to lightweight mask. The “water–like” ethyl cellulose (EC) was selected as the base polymer to “nourish” functional materials of gelatin (GE), β–cyclodextrin (βCD), and curcumin (Cur), thus forming a solution system with high binding energy differences and electrospinning into ultrafine bimodal nanofibers. The filtration efficiency for 0.3 μm NaCl particles, pressure drop, and quality factor were 99.25 %, 53 Pa, and 0.092 Pa−1, respectively; the bacteriostatic rates against Escherichia coli and Staphylococcus aureus were 99.9 % and 99.4 %, respectively; the formaldehyde adsorption capacity was 442 μg/g. This is the first report on antibacterial and formaldehyde–adsorbable high–performance air filter entirely made from bio–based materials. This simple strategy will greatly broaden the selection of materials for preparing high–performance multifunctional air filter, and promote the development of bio–based air filter.

Salinity alleviates arsenicstress-induced oxidative damage via antioxidative defense and metabolic adjustment in the root of the halophyte Salvadora persica.

Arsenic tolerance in the halophyte Salvadora persica is achieved by enhancing antioxidative defense and modulations of various groups of metabolites like amino acids, organic acids, sugars, sugar alcohols, and phytohormones. Salvadora persica is a facultative halophyte that thrives under high saline and arid regions of the world. In present study, we examine root metabolic responses of S. persica exposed to individual effects of high salinity (750mM NaCl), arsenic (600µM As), and combined treatment of salinity and arsenic (250mM NaCl + 600µM As) to decipher its As and salinity resistance mechanism. Our results demonstrated that NaCl supplementation reduced the levels of reactive oxygen species (ROS) under As stress. The increased activities of antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and glutathione reductase (GR) maintained appropriate levels of ROS [superoxide (O2•-) and hydrogen peroxide (H2O2)] under salinity and/or As stress. The metabolites like sugars, amino acids, polyphenols, and organic acids exhibited higher accumulations when salt was supplied with As. Furthermore, comparatively higher accumulations of glycine, glutamate, and cystine under combined stress of salt and As may indicate its role in glutathione and phytochelatins (PCs) synthesis in root. The levels of phytohormones such as salicylate, jasmonate, abscisic acid, and auxins were significantly increased under high As with and without salinity stress. The amino acid metabolism, glutathione metabolism, carbohydrate metabolism, tricarboxylic acid cycle (TCA cycle), phenylpropanoid biosynthesis, and phenylalanine metabolism are the most significantly altered metabolic pathways in response to NaCl and/or As stress. Our study decoded the important metabolites and metabolic pathways involved in As and/or salinity tolerance in root of the halophyte S. persica providing clues for development of salinity and As resistance crops.

Comparative Analysis of Phospholipase D (PLD) Gene Family in Camelina sativa and Brassica napus and Its Responses in Camelina Seedlings under Salt Stress

Phospholipases are among the important elements involved in lipid-dependent cell signaling that lead to the induction of downstream pathways. In the current study, phospholipases D (PLDs) gene family was characterized and compared in two important oilseed crops, Brassica napus and Camelina sativa. The results revealed that PLD has 33 members in Camelina sativa (CsPLD) and 41 members in Brassica napus (BnPLD). All studied PLDs showed a negative GRAVY value, indicating that PLDs are probably hydrophilic proteins. Phylogenetic analysis classified PLDs into five main subfamilies, including gamma, delta, beta, alpha, and zeta. According to evolution analysis, a different evolution process was observed between CsPLD and BnPLD. In addition, the results disclosed that most of the PLD genes have been segmentally duplicated under purifying selection. Cis-regulatory elements related to ABA and auxin responsiveness were found more in the upstream region of CsPLDs, while elements linked with MeJA responsiveness were observed more in the promoter region of BnPLDs. Analysis of the expression data showed that PLD alpha genes have a wide expression in most tissues. Quantitative expression analysis (qPCR) of CsPLD genes under salt stress, 200 mM of NaCl, was conducted in different time series. The results revealed that the CsPLD genes are involved in the response to salinity stress and their expression levels enhance with increasing salinity stress period. The outcomes of this research will be useful for future molecular works related to lipid signaling in oilseed plants.

Profiling of conserved orthologs and miRNAs for understanding their role in salt tolerance mechanism of Sesuvium portulacastrum L.

Sesuvium portulacastrum is a facultative halophyte capable of thriving in a saline environment. Despite molecular studies conducted to unravel its salt adaptation mechanism, there is a paucity of information on the role of salt-responsive orthologs and microRNAs (miRNAs) in this halophyte. Here, we searched the orthology to identify salt-responsive orthologs and miRNA targets of Sesuvium using the Arabidopsis genome. The relative fold change of orthologs, conserved miRNAs, and miRNA targets of Sesuvium was analyzed under 100mM (LS) and 250mM NaCl (HS) treatment at 24h using qRT-PCR. The comparison between the expression of Sesuvium orthologs and Arabidopsis orthologs (Arabidopsis eFP browser database) was used to identify differentially expressed genes. Upon salt treatment, we found that SpCIPK3 (1.95-fold in LS and 2.90-fold in HS) in Sesuvium roots, and SpNHX7 (1.61-fold in LS and 6.39-fold in HS) and, SpSTPK2 (2.54-fold in LS and 7.65-fold in HS) in Sesuvium leaves were upregulated in a salt concentration-specific manner. In Arabidopsis, these genes were either downregulated or did not show significant variation, implicating its significance in the halophytic nature of Sesuvium. Furthermore, miRNAs like miR394a, miR396a, and miR397a exhibited a negative correlation with their targets-Frigida interacting protein 1, Cysteine proteinases superfamily protein, and Putative laccase, respectively under different salt treatments. The study revealed that the high salt tolerance in Sesuvium is associated with distinct transcriptional reprogramming, hence, to gain holistic mechanistic insights, global-scale profiling is required.

Structural, developmental and functional analyses of leaf salt glands of mangrove recretohalophyte Aegiceras corniculatum.

Salt secretion is an important strategy used by the mangrove plant Aegiceras corniculatum to adapt to the coastal intertidal environment. However, the structural, developmental and functional analyses on the leaf salt glands, particularly the salt secretion mechanism, are not well documented. In this study, we investigated the structural, developmental and degenerative characteristics and the salt secretion mechanisms of salt glands to further elucidate the mechanisms of salt tolerance of A. corniculatum. The results showed that the salt gland cells have a large number of mitochondria and vesicles, and plenty of plasmodesmata as well, while chloroplasts were found in the collecting cells. The salt glands developed early and began to differentiate at the leaf primordium stage. We observed and defined three stages of salt gland degradation for the first time in A. corniculatum, where the secretory cells gradually twisted and wrinkled inward and collapsed downward as the salt gland degeneration increased and the intensity of salt gland autofluorescence gradually diminished. In addition, we found that the salt secretion rate of the salt glands increased when the treated concentration of NaCl increased, reaching the maximum at 400mM NaCl. The salt-secreting capacity of the salt glands of the adaxial epidermis is significantly greater than that of the abaxial epidermis. The real-time quantitative PCR results indicate that SAD2, TTG1, GL2 and RBR1 may be involved in regulating the development of the salt glands of A. corniculatum. Moreover, Na+/H+ antiporter, H+-ATPase, K+ channel and Cl- channel may play important roles in the salt secretion of salt glands. In sum mary, this study strengthens the understanding of the structural, developmental and degenerative patterns of salt glands and salt secretion mechanisms in mangrove recretohalophyte A. corniculatum, providing an important reference for further studies at the molecular level.

A-209 Application of Bilirubin Oxidase for Improvement of False Positive Error Caused by Bilirubin on Cholesterol Efflux Capacity Assay by Immobilize Liposome-Bound Gel Beads method

Abstract Background High density lipoprotein (HDL) exerts various atheroprotective functions including cholesterol efflux capacity (CEC). HDL can attenuate lipid burden at atherosclerotic lesion by CEC. Based on the HDL`s role for moderate atherosclerosis, HDL-cholesterol level which indicates the amount of HDL has been evaluated to assess the risk of cardiovascular disease (CVD). Nevertheless, many clinical studies demonstrated that HDL-cholesterol level does not always reflect the risk of CVD, and CEC which represents the quality of HDL is considered as surrogate biomarker for CVD. CEC is prospective biomarker for CVD risk assessment, however, CEC measurement encounters barriers for clinical application because of its requirements of cultured cell and radioactive substance for conventional CEC assay. To overcome these problems, we invented a novel CEC assay called immobilized liposome-bound gel beads (ILG) method. This method is cell-free assay and utilizes a fluorescence substance as cholesterol tracer. Although the ILG method is useful assay for clinical application, previous study revealed that bilirubin caused false positive error on CEC value. Hence, current ILG method might produce incorrect CEC evaluation for patients with hyperbilirubinemia and even healthy subjects within the range of biological variation of bilirubin. In this study, we improved the influence of bilirubin for ILG method by using bilirubin oxidase (BOD). Methods BOD (Asahi Kasei Corp.) was added to 10 mM Tris-HCl (pH 7.4) containing 150 mM of NaCl and 1 mM of Na2EDTA (Buffer A). Bilirubin from ‘Interference check A Plus’ (Sysmex Inc.) was added to serum (free-: 10 mg/dL, conjugated-:9.7 mg/dL), and apoB-depleted serum (BDS) was derived from the bilirubin additive serum using polyethylene glycol. After the prepared bilirubin additive BDS was incubated with BOD-containing Buffer A for 16 h, the absorbance spectrum was analyzed. In addition, the time course of bilirubin decrement was monitored during 16 h-incubation. We further measured the fluorescence intensity of bilirubin additive BDS incubated with BOD-containing Buffer A. Using the newly developed BOD-containing Buffer A for ILG method, CEC of bilirubin additive serum was evaluated. Finally, we measured CEC of 4 healthy individuals by conventional and the improved ILG method. The CEC value was standardized by fluorescence intensity of reference sample which was measured in every assay. Results BOD contained in Buffer A could convert bilirubin to biliverdin from results of absorbance spectrum. According to the time course of bilirubin decrement, both free- and conjugated-bilirubin were oxidized to biliverdin in approximately 6 h. By converting bilirubin to biliverdin, fluorescence light was weakened greatly. We confirmed that there was no significant difference of CEC values between non bilirubin-additive serum and bilirubin additive serum. Compared healthy individual CEC values measured by conventional and improved ILG method, all subjects showed significant decrease of CEC values from the improved method, and false positive error caused by bilirubin was ameliorated. Conclusion In this study, we achieved to improve the positive error caused by bilirubin on CEC assay using ILG method. This improvement would contribute to more accurate CEC assessment by ILG method and advance the clinical application of this method.

Evaluation of the Effects of Salinity Stress on Yield Parameters of Soybeans (Glycine max) Cultivated in Obubra Local Government Area of Cross River State, Nigeria

A pot experiment was conducted in the screen house at the Cross River University of Technology, Obubra Campus to evaluate the effect of different salt concentrations on the yield of three different varieties of soybeans (Glycine max). The experiment was laid in complete randomized design (CRD) with twenty replicates for each variety. Yield parameters which include number of pods per plant, 100 seed weight (g) and seed yield were measured, and data collected was subjected to statistical analysis using Analysis of variance (ANOVA) and means were compared using Duncan’s New Multiple Range Test (DNMRT). The results showed that salinity stress led to a significant reduction in number of pods per plant over control. At 30mM Nacl which was the highest level of saline water TGX 1987-10F had a better salt tolerance level as compared to other varieties, which might be as a result of some salt tolerance genes. 100 seed weight (g) reduced significantly under salinity stress as compared with the control, but TGX 1987-10F showed better salt tolerance level as compared with other varieties. Seed yield per plant decreased significantly with increasing salinity levels and a greater reduction was observed in TGX 1448-2E and TGX 1835-10E. It was concluded that Soybean is a sensitive plant to salinity stress, but the extent of this sensitivity varies among varieties. TGX 1987-10F showed a better tolerance level as compared with other varieties. Therefore, it is recommended that TGX 1987-10F can be cultivated in saline areas.

An enhanced activity and thermostability of chimeric Bst DNA polymerase for isothermal amplification applications.

Loop-mediated isothermal amplification (LAMP) is a widely used method for clinical diagnosis, customs quarantine, and disease prevention. However, the low catalytic activity of Bst DNA polymerase has made it challenging to develop rapid and reliable point-of-care testing. Herein, we developed a series of Bst DNA polymerase mutants with enhanced activity by predicting and analyzing the activity sites. Among these mutants, single mutants K431D and K431E showed a 1.93- and 2.03-fold increase in catalytic efficiency, respectively. We also created a chimeric protein by fusing the DNA-binding domain of DNA ligase from Pyrococcus abyssi (DBD), namely DBD-K431E, which enabled real-time LAMP at high temperatures up to 73 ℃ and remained active after heating at 70 ℃ for 8h. The chimeric DBD-K431E remained active in the presence of 50 U/mL heparin, 10% ethanol, and up to 100mM NaCl, and showed higher activity in 110mM (NH4)2SO4, 110mM KCl, and 12mM MgSO4. Notably, it generated a fluorescence signal during the detection of Salmonella typhimurium at 2 × 102 ag/μL of genomic DNA and 1.24CFU/mL of bacterial colony, outperforming the wild type and the commercial counterpart Bst 2.0. Our results suggest that the DBD-K431E variant could be a promising tool for general molecular biology research and clinical diagnostics. KEY POINTS: • Residue K431 is probably a key site of Bst DNA polymerase activity • The chimeric DBD-K431E is more inhibitor tolerant and thermostable than Bst-LF • The DBD-K431E variant can detect Salmonella typhimurium at 102 ag/μL or 100CFU/mL.

Characterization of rhizobia for beneficial traits that promote nodulation in legumes under abiotically stressed conditions.

The growing interest in using rhizobia as inoculants in sustainable agricultural systems has prompted the screening of rhizobia species for beneficial traits that enhance nodulation and nitrogen fixation under abiotic stressed conditions. This study reports phenotypic and phylogenetic characterization of rhizobia strains previously isolated from the root nodules of several indigenous and exotic legumes growing in South Africa and other countries. The Rhizobia strains were screened for their ability to tolerate various abiotic stresses (temperature 16, 28, and 36 °C; acidity/alkalinity pH 5, 7, and 9; heavy metals 50, 100, and 150mM AlCl3.6H2O; and salinity 50, 100, and 150mM NaCl). Phylogenetic characterization of the isolates was determined using multilocus sequence analysis of the 16S rRNA, recA, acdS, exoR, nodA, and nodC genes. The analysis indicated that the isolates are phylogenetically related to Sinorhizobium, Bradyrhizobium, Rhizobium, Mesorhizobium, and Aminobacter genera and exhibited significant variations in their tolerance to abiotic stresses. Amid the increasing threats of the global stresses, these current results provide baseline information in the selection of rhizobia for use as inoculants under extreme temperatures, acidity/alkalinity, and salinity stress conditions in South Africa.

Glutathione Transferases Are Involved in the Genotype-Specific Salt-Stress Response of Tomato Plants.

Glutathione transferases (GSTs) are one of the most versatile multigenic enzyme superfamilies. In our experiments, the involvement of the genotype-specific induction of GST genes and glutathione- or redox-related genes in pathways regulating salt-stress tolerance was examined in tomato cultivars (Solanum lycopersicum Moneymaker, Mobil, and Elán F1). The growth of the Mobil plants was adversely affected during salt stress (100 mM of NaCl), which might be the result of lowered glutathione and ascorbate levels, a more positive glutathione redox potential (EGSH), and reduced glutathione reductase (GR) and GST activities. In contrast, the Moneymaker and Elán F1 cultivars were able to restore their growth and exhibited higher GR and inducible GST activities, as well as elevated, non-enzymatic antioxidant levels, indicating their enhanced salt tolerance. Furthermore, the expression patterns of GR, selected GST, and transcription factor genes differed significantly among the three cultivars, highlighting the distinct regulatory mechanisms of the tomato genotypes during salt stress. The correlations between EGSH and gene expression data revealed several robust, cultivar-specific associations, underscoring the complexity of the stress response mechanism in tomatoes. Our results support the cultivar-specific roles of distinct GST genes during the salt-stress response, which, along with WRKY3, WRKY72, DREB1, and DREB2, are important players in shaping the redox status and the development of a more efficient stress tolerance in tomatoes.

The potential of seaweed extracts as a biostimulant for improving salt stress tolerance of Solanum lycopersicum L

The present investigation aimed to examine the effects of seaweed extracts (SWE) on tomato plants under saline conditions (50 mM of NaCl). The current findings have shown that the SWE obtained from Jania rubens (J. rubens) gave better results compared to those prepared from the other two seaweeds; Dictyota dichotoma (D. dichotoma) and Gelidium sesquipedale (G. sesquipedale). Indeed, under salt stress, the application of fresh seaweed at 2% significantly (p ≤ 0.05) increased the plant height (26.28 cm ± 0.95) compared with the non-treated stressed control (17.65 cm ± 1.04). Based on these results the effect of J. rubens on some biological and biochemical parameters of tomato plants was evaluated. In fact, increased contents of chlorophylls, total soluble sugars (TSS), and total free amino acids (TFAA) were observed in seaweed-treated plants compared to the control plants. Moreover, the treatment of stressed plants with SWE revealed a significant (p ≤ 0.05) improvement in antioxidant enzyme activities such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferase (GST). The extract also showed an increase in the enzyme activities of glutamate dehydrogenase (GDH) and phosphoenolpyruvate carboxylase (PEPC), which are implicated in the nitrogen and carbon metabolism, respectively. Furthermore, the analysis of the chemical composition of the liquid seaweed extracts (fresh and dried) has shown that they contain bioactive compounds such as polyphenols, flavonoids, soluble sugars, and amino acids, which can be responsible for the tomato's tolerance to salinity. Therefore, the SWE tested in the present study can be used as a biostimulant to enhance the salt stress tolerance of tomato plants.

Overexpression of chloroplastic Zea mays NADP-malic enzyme (ZmNADP-ME) confers tolerance to salt stress in Arabidopsis thaliana.

The C4 plants photosynthesize better than C3 plants especially in arid environment. As an attempt to genetically convert C3 plant to C4, the cDNA of decarboxylating C4 type NADP-malic enzyme from Zea mays (ZmNADP-ME) that has lower Km for malate and NADP than its C3 isoforms, was overexpressed in Arabidopsis thaliana under the control of 35S promoter. Due to increased activity of NADP-ME in the transgenics the malate decarboxylation increased that resulted in loss of carbon skeletons needed for amino acid and protein synthesis. Consequently, amino acid and protein content of the transgenics declined. Therefore, the Chl content, photosynthetic efficiency (Fv/Fm), electron transport rate (ETR), the quantum yield of photosynthetic CO2 assimilation, rosette diameter, and biomass were lower in the transgenics. However, in salt stress (150mM NaCl), the overexpressers had higher Chl, protein content, Fv/Fm, ETR, and biomass than the vector control. NADPH generated in the transgenics due to increased malate decarboxylation, contributed to augmented synthesis of proline, the osmoprotectant required to alleviate the reactive oxygen species-mediated membrane damage and oxidative stress. Consequently, the glutathione peroxidase activity increased and H2O2 content decreased in the salt-stressed transgenics. The reduced membrane lipid peroxidation and lower malondialdehyde production resulted in better preservation, of thylakoid integrity and membrane architecture in the transgenics under saline environment. Our results clearly demonstrate that overexpression of C4 chloroplastic ZmNADP-ME in the C3 Arabidopsis thaliana, although decrease their photosynthetic efficiency, protects the transgenics from salinity stress.

Integration of genome-wide association studies reveal loci associated with salt tolerance score of rice at the seedling stage.

Salt threatens rice cultivation in many countries. Hence, breeding new varieties with high salt tolerance is important.A panel of 2,391 rice accessions from the 3K Rice Genome Project was selected to evaluate salt tolerance via the standard evaluation score (SES) in hydroponics under 60mM NaCl at the seedling stage. Three sub-population panels including 1,332, 628, and 386 accessions from the original 2,391 ones were constructed based on low relatedness revealed by a phylogenetic tree generated by Archaeopteryx Tree. A genome-wide association study (GWAS) was conducted on the entire and sub-population panels using SES data and a selection of 5, 10, 20, and 40% of SNPs selected from the original 1,011,601 SNPs by filtering minor allele frequency > 5% and missing rate < 5%. To perform GWAS, three methods implemented in three different software packages were utilized.Using the integration of GWAS programs, a total of four QTLs associated with SES scores were identified in different panels. Some QTLs co-located with previously detected QTL-related traits. qSES1.1 was detected in three panels, qSES1.3 and qSES2.1 in two panels, and qSES3.1 in one panel through GWAS by all three methods used and selected SNPs. These four QTLs were selected to detect candidate genes. Combining gene-based association study plus haplotype analysis in the entire population and the three sub-populations let us shortlist three candidate genes, viz. LOC_Os01g23640 and LOC_Os01g23680 for qSES1.1, and LOC_Os01g71240 for qSES1.3 region affecting salt tolerance. The identified QTLs and candidate genes provided useful materials and genetic information for future functional characterization and genetic improvement of salt tolerance in rice.

Ecophysiological responses of Glycine max L. under single and combined cadmium and salinity stresses.

Soil contamination by cadmium (Cd) and degradation by salinity are likely to become one of the most important problems hindering food production and human health. However, their combined effect on crops is still ambiguous. A hydroponic study was made to investigate the separate and combined exposure of 100 µM Cd and 150 µM NaCl on soybeans (Glycine max L.) growth, photosynthetic pigment, and antioxidant systems for 7 days. Both Cd and NaCl, applied separately decreased the seedlings growth, chlorophyll contents and caused oxidative stress. However, the toxic effects of salinity applied alone were more pronounced. Interestingly, combined exposure of Cd and NaCl induced higher decreases in all growth parameters and lipid peroxidation than single exposure suggesting synergistic effects. The results implicate that the phytotoxicity of both stressors can be associated with redox status imbalance. Our finding may provide insight into the physiological mechanisms of heavy metal exposure and salinity stress tolerance in soybeans and suggest that saline stress changes the effects of Cd toxicity on crops in Cd-salt-polluted soils.

SALINITY STRESS AS AN ABIOTIC FACTOR AT GERMINATION STAGE ON DRY BEAN (Phaseolus vulgaris L.) CULTIVARS

The study focused on germination parameters as the most critical stage of plant development in dry bean cultivars under different salt treatment. For two used cultivars (Akman-98, Karaman-2016) the data on germination percentage, mean germination time, seedling shoot length, seedling root length, seedling length and seedling vigor indexes were reached under the different salinity levels of irrigation water (0 mM, 25 mM, 50 mM, 100 mM, 150 mM, and 200 mM of NaCl) in Petri plates. The data indicates that these parameters could be used as screening the dry bean cultivars against salt stress levels. This study was carried out in a Completely Randomized Design (CRD) with a total of 12 treatments (6 salinity x 2 cultivars) for the germination and seedling data each comprising of three replicates. The results demonstrated that; i) From the overall observation of the germination characters, at 100 mM and over salt treatments showed decreasing in the germination percentage, the seedling length and the seedling vigor index in the mean of the cultivars, ii) Significantly decreasing in the seedling shoot length were observed in the mean of the cultivars at just after 25 mM and gradually at all salt concentrations, iii) Although the root length showed increasing in 25 and 50 mM treatments than the control plants, a sudden decrease occurred after 100 mM salt treatment in the mean of the cultivars and in each cultivars separately, iv) The mean germination time were sharply in increasing starting with 25 mM treatment in the mean of the cultivars, v) Except the seedling shoot length, in the mean of all the salt treatments between the cultivars did not show statistically differences in the calculated parameters, vi) Any correlation was found between the salt concentrations and the cultivars.

The Knockdown of AUXIN RESPONSE FACTOR 2 Confers Enhanced Tolerance to Salt and Drought Stresses in Tomato (Solanum lycopersicum L.).

Auxin response factors (ARFs) act as key elements of the auxin-signaling pathway and play important roles in the process of a plant's growth, development, and response to environmental conditions. We studied the implication of the SlARF2 gene in the tomato response to salt (150 mM of NaCl) and drought (15% PEG 20000) stresses. The functional characterization of SlARF2 knockdown tomato mutants revealed that the downregulation of this gene enhanced primary root length and root branching and reduced plant wilting. At the physiological level, the arf2 mutant line displayed higher chlorophyll, soluble sugars, proline, and relative water contents as well as lower stomatal conductance and a decreased malondialdehyde content. Moreover, SlARF2 knockdown tomato mutants demonstrated higher activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) under salt and drought stresses than the wild type. Indeed, the stress tolerance of the arf2 mutant was also reflected by the upregulation of stress-related genes involved in ROS scavenging and plant defense, including SOD, CAT, dehydration-responsive element-binding protein, and early responsive to dehydration, which can ultimately result in a better resistance to salt and drought stresses. Furthermore, the transcriptional levels of the Δ1-pyrroline-5-carboxylate synthase (P5CS) gene were upregulated in the arf2 mutant after stress, in correlation with the higher levels of proline. Taken together, our findings reveal that SlARF2 is implicated in salt and drought tolerance in tomato and provides some considerable elements for improving the abiotic stress tolerance and increasing the crop yields of tomato.

Evaluating the genotoxicity of salinity stress and secondary products gene manipulation in lime, Citrus aurantifolia, plants.

Salinity is a significant abiotic stress that has a profound effect on growth, the content of secondary products, and the genotoxicity of cells. Lime, Citrus aurantifolia, is a popular plant belonging to the family Rutaceae. The interest in cultivating this plant is due to the importance of its volatile oil, which is included in many pharmaceutical industries, but C. aurantifolia plants are affected by the NaCl salinity levels. In the present study, a comet assay test has been applied to evaluate the genotoxic impact of salinity at 0, 50, 100, and 200 mM of NaCl on C. aurantifolia tissue-cultured plants. Furthermore, terpene gene expression was investigated using a semi-quantitative real-time polymerase chain reaction. Results from the two analyses revealed that 200 mM of NaCl stress resulted in high levels of severe damage to the C. aurantifolia plants' DNA tail 21.8%, tail length 6.56 µm, and tail moment 3.19 Unit. The relative highest expression of RtHK and TAT genes was 2.08, and 1.693, respectively, when plants were exposed to 200 mM of NaCl, whereas pv4CL2RT expressed 1.50 in plants subjected to 100 mM of NaCl. The accumulation of transcripts for the RTMYB was 0.951 when plants were treated with NaCl at 50 mM, and RtGPPS gene was significantly decreased to 0.446 during saline exposure at 100 mM. We conclude that the comet assay test offers an appropriate tool to detect DNA damage as well as RtHK, TAT, and pv4CL2RT genes having post-transcriptional regulation in C. aurantifolia plant cells under salinity stress. Future studies are needed to assess the application of gene expression and comet assay technologies using another set of genes that show vulnerability to different stresses on lime and other plants.