Multivariate characterization of salicylic acid and potassium induced physio-biochemical and phytoremediation responses in quinoa exposed to lead and cadmium contamination.

The levels of soils pollutants such as lead (Pb) and cadmium (Cd) have significantly increased recently resulting in ecological disturbances and threatening crop production. Various amendments have been employed to enhance the tolerance of crops to withstand Cd and Pb stresses. However, the role of combined application of potassium (K) and of salicylic acid (SA) for Cd and Pb stress mitigation and phytoremediation by quinoa (Chenopodium quinoa Willd) has not been comprehended well. In the present study, the effect of 10 mM K and 0.1 mM SA was tested on the quinoa plants subjected to 250 µM Pb and/or 100 µM Cd. The Pb and Cd treatments were applied separately or together. Phytotoxicity induced by Pb and Cd resulted in drastic decrease (>60%) in chlorophyll contents, stomatal conductance, and plant biomass. The collective treatment of Pb and Cd induced an increase in the concentration of hydrogen peroxide (13-fold) and lipid peroxidation (16-fold) that resulted in a 61% reduction in membrane stability. The application of 10 mM K and/or 0.1 mM SA was remarkable in mitigating the adverse effect of Pb and Cd. The reduction in plant biomass was 17% when 10 mM K and 0.1 mM SA were applied together under the combined treatment of both the metals. The simultaneous application of K and SA effectively mitigated oxidative stress by enhancing the activities of superoxide dismutase, peroxidase, ascorbate peroxidase, and catalase by 12, 10, 7 and 10-folds respectively. The positive effect of K and SA on these attributes resulted in a remarkable reduction in metal accumulation and translocation and lipid peroxidation. The stressed plants supplemented with K and SA exhibited a significant improvement in the membrane stability index, chlorophyll content, and stomatal conductance. This study concluded that the combined application of K and SA could be a good approach for reducing Pb and Cd phytotoxicity in quinoa and enhancing their phytostabilization potential in the contaminated soils.

Synthesis, structural characterization and in vitro pharmacological properties of betanin-encapsulated chitosan nanoparticles.

Betanin, a natural food color and the only betalain, is approved for use in pharmaceutical and food industries as natural antioxidative and preservative agent, respectively. However, the antioxidant power and health-promoting properties of betanin have been disregarded due to its low stability in physiological conditions. Therefore, this study is designed to synthesize and evaluate in vitro pharmacological characteristics of betanin-encapsulated chitosan nanoparticles (ChBetNPs). ChBetNPs were synthesized by ionic gelation method and characterized by DLS, UV, FTIR, SEM and zeta potential analysis. The encapsulation efficiency (EE) and in vitro release kinetics were analyzed using spectrophotometric technique for quantifying the encapsulated amount of betanin in ChBetNPs as a function of time. The antioxidant activity of ChBetNPs was analyzed by DPPH and H2O2 radical scavenging assays, anti-inflammatory activity by protein denaturation and human RBCs stabilization assays, and anti-acetylcholinesterase activity using standard protocol with minor modifications. Unloaded chitosan nanoparticles (CSNPs) were found to be sized at 161.4 ± 5.75 nm while an increase in the size to 270.3 ± 8.50 nm was noticed upon encapsulating betanin. EE of ChBetNPs was measured to be ∼87.5%. The IC50 of ChBetNPs depicted significant free radical scavenging activities as compared to CSNPs. Similarly, a strong anti-inflammatory activity of ChBetNPs was noted. Significant decrease in acetylcholinesterase activity by ChBetNPs was measured (IC50 0.5255 µg/mL vs. control 26.09 µg/mL). The vegetables coated with 3% ChBetNPs showed decreased weight loss as compared to uncoated control. ChBetNPs was shown to exhibit strong antioxidant, anti-inflammatory and anti-acetylcholinesterase activities thus making it a significant therapeutic agent for the management of Alzheimer's disease.

Vitamin C supplementation ameliorates liver function profile and antiviral treatment response in Hepatitis C patients.

An imbalance between oxidative stress and antioxidative defence mediates a variety of diseases pathogenesis. The present study aims to assess the possible outcome of supplementation of oral vitamin-C (VC), an antioxidant, in Viral Hepatitis C (HCV) treatment as an adjuvant therapy. 200 HCV-patients were selected, 100 were given Vitamin-C (1000 mg/day) along with anti HCV treatment (sofosbuvir plus daclatasvir) while the other 100 took only anti-HCV treatment for 4weeks. The serum ascorbic acid (Vitamin-C) levels and functions of the liver were tested before and after the VC supplementation. HCV patients with relatively low serum ascorbic acid showed significant improvement after the intake of vitamin C. After 4 weeks of treatment, AST, ALP, albumin, and total, direct and indirect bilirubin were improved significantly in the VC group; whereas only ALT and indirect bilirubin were improved in both groups when associated with the control subjects. Comparing the two treatment groups at 4weeks; more effective and significant improvement was observed in ALT (p<0.01), AST (p<0.001), direct (p<0.01) and indirect bilirubin (p<0.001), total proteins (p<0.001) and albumin (p<0.05) in patients with VC supplementation on anti-viral treatment compared to only anti-viral treatment group. Thus, VC supplementation improves the antiviral therapy outcome by bestowing a beneficial effect in minimizing liver damage in HCV cases.

Alleviation of cadmium stress in rice by inoculation of Bacillus cereus.

Heavy metal resistant bacteria are of great importance because they play a crucial role in bioremediation. In the present study, 11 bacterial strains isolated from industrial waste were screened under different concentrations of cadmium (Cd) (100 µM and 200 µM). Among 11 strains, the Cd tolerant Bacillus cereus (S6D1-105) strain was selected for in vitro and in vivo studies. B. cereus was able to solubilize potassium, and phosphate as well as produce protease and siderophores during plate essays. Moreover, we observed the response of hydroponically grown rice plants, inoculated with B. cereus which was able to promote plant growth, by increasing plant biomass, chlorophyll contents, relative water content, different antioxidant enzymatic activity such as catalase, superoxide dismutase, ascorbate peroxidase, polyphenol oxidase and phenylalanine ammonia-lyase and reducing malondialdehyde content in both roots and leaves of rice plants under Cd stress. Our results showed that the B. cereus can be used as a biofertilizer which might be beneficial for rice cultivation in Cd contaminated soils.

Exploring the genetic potential of Pakistani soybean cultivars through RNA-seq based transcriptome analysis.

BACKGROUND: Soybean is largely grown and considered among the top oilseed crops. Three Pakistani cultivars, NARC-II (N), Swat-84 (S), and Rawal-I (R) were employed for RNA-Seq based transcriptome analysis to explore their genetic potential and performance in our local environment. METHODS AND RESULTS: We grew the plants in glass house at same conditions and sampled leaves for RNA-Seq analysis in triplicate for each variety. We retrieved 2225 differentially expressed genes (DEGs) between S vs R, 2591 DEGs between S vs N, and 1221 DEGs between R vs N cultvars. These genes consist of transcription factors representing Basic Helix-loop Helix, myeloblastosis, ethylene response factors, and WRKY amino acid motif (WRKY) type major families that were up-regulated. KEGG pathway analysis revealed that MAPK, plant hormone signal transduction, and Phenylpropanoid biosynthesis pathways were the most dominant pathways involved in plant defense and growth. Comparative analysis showed that Swat-84 (S) cultivar had better gene expression among these varieties having higher number of DEGs, where mostly genes related to important phenotypic traits were up regulated. CONCLUSIONS: This is a pilot study to investigate and functionally characterise the DEG involved in the stress response in the cultivars studied.

Drought-tolerant Bacillus megaterium isolated from semi-arid conditions induces systemic tolerance of wheat under drought conditions.

KEY MESSAGE: A detailed study of the response of wheat plants, inoculated with drought-tolerant PGPR is studied which would be beneficial to achieve genetic improvement of wheat for drought tolerance. Drought stress, a major challenge under current climatic conditions, adversely affects wheat productivity. In the current study, we observed the response of wheat plants, inoculated with drought-tolerant plant growth-promoting rhizobacteria (PGPR) Bacillus megaterium (MU2) and Bacillus licheniformis (MU8) under induced drought stress. In vitro study of 90 rhizobacteria exhibited 38 isolates showed one or more plant growth-promoting properties, such as solubilization of phosphorus, potassium, and exopolysaccharide production. Four strains revealing the best activities were tested for their drought-tolerance ability by growing them on varying water potentials (- 0.05 to - 0.73 MPa). Among them, two bacterial strains Bacillus megaterium and Bacillus licheniformis showed the best drought-tolerance potential, ACC deaminase activities, IAA production, and antagonistic activities against plant pathogens. Additionally, these strains when exposed to drought stress (- 0.73 MPa) revealed the induction of three new polypeptides (18 kDa, 35 kDa, 30 kDa) in Bacillus megaterium. We determined that 106 cells/mL of Bacillus megaterium and Bacillus licheniformis were enough to induce drought tolerance in wheat under drought stress. These drought-tolerant strains increased the germination index (11-46%), promptness index (16-50%), seedling vigor index (11-151%), fresh weight (35-192%), and dry weight (58-226%) of wheat under irrigated and drought stress. Moreover, these strains efficiently colonized the wheat roots and increased plant biomass, relative water content, photosynthetic pigments, and osmolytes. Upon exposure to drought stress, Bacillus megaterium inoculated wheat plants exhibited improved tolerance by enhancing 59% relative water content, 260, 174 and 70% chlorophyll a, b and carotenoid, 136% protein content, 117% proline content and 57% decline in MDA content. Further, activities of defense-related antioxidant enzymes were also upregulated. Our results revealed that drought tolerance was more evident in Bacillus megaterium as compared to Bacillus licheniformis. These strains could be effective bioenhancer and biofertilizer for wheat cultivation in arid and semi-arid regions. However, a detailed study at the molecular level to deduce the mechanism by which these strains alleviate drought stress in wheat plants needs to be explored.

Sodium nitroprusside application improves morphological and physiological attributes of soybean (Glycine max L.) under salinity stress.

Salinity is among the major abiotic stresses negatively affecting the growth and productivity of crop plants. Sodium nitroprusside (SNP) -an external nitric oxide (NO) donor- has been found effective to impart salinity tolerance to plants. Soybean (Glycine max L.) is widely cultivated around the world; however, salinity stress hampers its growth and productivity. Therefore, the current study evaluated the role of SNP in improving morphological, physiological and biochemical attributes of soybean under salinity stress. Data relating to biomass, chlorophyll and malondialdehyde (MDA) contents, activities of various antioxidant enzymes, ion content and ultrastructural analysis were collected. The SNP application ameliorated the negative effects of salinity stress to significant extent by regulating antioxidant mechanism. Root and shoot length, fresh and dry weight, chlorophyll contents, activities of various antioxidant enzymes, i.e., catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX) were improved with SNP application under salinity stress compared to control treatment. Similarly, plants treated with SNP observed less damage to cell organelles of roots and leaves under salinity stress. The results revealed pivotal functions of SNP in salinity tolerance of soybean, including cell wall repair, sequestration of sodium ion in the vacuole and maintenance of normal chloroplasts with no swelling of thylakoids. Minor distortions of cell membrane and large number of starch grains indicates an increase in the photosynthetic activity. Therefore, SNP can be used as a regulator to improve the salinity tolerance of soybean in salt affected soils.

Biochemical Profiling and Elucidation of Biological Activities of Beta vulgaris L. Leaves and Roots Extracts.

RESEARCH BACKGROUND: Red beet (Beta vulgaris L.) is commercially grown in Punjab and Khyber Pakhtunkhwa (KPK) regions while cultivated as vegetable in Baluchistan and Sindh regions of Pakistan. It is well known for its health-promoting role in several clinical and pathologic outcome due to abundance of betalains and other bioactive compounds. The purpose of study was to interpret bioactivity of of B. vulgaris leaves (BvLM) and roots (BvRM) extracts for finding natural cure of neurodegenerative diseases (NDs). EXPERIMENTAL APPROACH: BvLM and BvRM extracts were evaluated for phytochemical composition, antioxidant, anti-inflammatory and anticholinesterase potential using standard protocols with modifications. RESULTS: Phytochemicals analysis of BvLM and BvRM extracts depicted the presence of flavonoids, phenols, alkaloids, saponins and glycosides. The IC50 values for free radical scavenging activity for BvRM and BvLM showed that BvLM (DPPH: 2.20 ± 0.72 µg/mL, H 2 O 2 : 0.0519 ± 1.02 µg/mL) is more significant as compared to BvRM (DPPH: 2.312 ± 0.72 µg/mL, H 2 O 2 : 2.668 ± 0.49 µg/mL). BvLM showed significant protection against heat induced hemolysis of HRBCs and protein denaturation (2.322 ± 0.1 > 2.324 ± 0.06 µg/mL) as compared to BvRM (8.572 ± 0.2 > 50.18 ± 1.0 µg/mL). Both extracts found to exhibit strong inhibitory potential against acetylcholinesterase enzyme. DISCUSSION/CONCLUSION: Our study highlighted B. vulagris extracts as rich and nutritious source of antioxidants, anti-inflammatory and cholinesterase inhibitors that could be helpful in preventing and treating neurodegenerative disorders (NDs). In consideration of multifactorial and complex etiology of NDs, BvLM and BvRM extracts would be apt candidates for development of therapeutic strategy for management of multiple cognitive disorders.

NHX-Type Na+/H+ Antiporter Gene Expression Under Different Salt Levels and Allelic Diversity of HvNHX in Wild and Cultivated Barleys.

Salinity tolerance is a multifaceted trait attributed to various mechanisms. Wild barley is highly specialized to grow under severe environmental conditions of Tibet and is well-known for its diverse germplasm with high tolerance to abiotic stresses. The present study focused on determining the profile of the expression of isoforms of the HvNHX gene in 36 wild and two cultivated barley under salt stress. Our findings revealed that in leaves and roots, expression of HvNHX1 and HvNHX3 in XZ16 and CM72 was upregulated at all times as compared with sensitive ones. The HvNHX2 and HvNHX4 isoforms were also induced by salt stress, although not to the same extent as HvNHX1 and HvNHX3. Gene expression analysis revealed that HvNHX1 and HvNHX3 are the candidate genes that could have the function of regulators of ions by sequestration of Na+ in the vacuole. HvNHX1 and HvNHX3 showed a wide range of sequence variations in an amplicon, identified via single-nucleotide polymorphisms (SNPs). Evaluation of the sequencing data of 38 barley genotypes, including Tibetan wild and cultivated varieties, showed polymorphisms, including SNPs, and small insertion and deletion (INDEL) sites in the targeted genes HvNHX1 and HvNHX3. Comprehensive analysis of the results revealed that Tibetan wild barley has distinctive alleles of HvNHX1 and HvNHX3 which confer tolerance to salinity. Furthermore, less sodium accumulation was observed in the root of XZ16 than the other genotypes as visualized by CoroNa-Green, a sodium-specific fluorophore. XZ16 is the tolerant genotype, showing least reduction of root and leaf dry weight under moderate (150 mM) and severe (300 mM) NaCl stress. Evaluation of genetic variation and identification of salt tolerance mechanism in wild barley could be promoting approaches to unravel the novel alleles involved in salinity tolerance.

Halotolerant rhizobacteria Pseudomonas pseudoalcaligenes and Bacillus subtilis mediate systemic tolerance in hydroponically grown soybean (Glycine max L.) against salinity stress.

Salt stress is one of the devastating factors that hampers growth and productivity of soybean. Use of Pseudomonas pseudoalcaligenes to improve salt tolerance in soybean has not been thoroughly explored yet. Therefore, we observed the response of hydroponically grown soybean plants, inoculated with halotolerant P. pseudoalcaligenes (SRM-16) and Bacillus subtilis (SRM-3) under salt stress. In vitro testing of 44 bacterial isolates revealed that four isolates showed high salt tolerance. Among them, B. subtilis and P. pseudoalcaligenes showed ACC deaminase activity, siderophore and indole acetic acid (IAA) production and were selected for the current study. We determined that 106 cells/mL of B. subtilis and P. pseudoalcaligenes was sufficient to induce tolerance in soybean against salinity stress (100 mM NaCl) in hydroponics by enhancing plant biomass, relative water content and osmolytes. Upon exposure of salinity stress, P. pseudoalcaligenes inoculated soybean plants showed tolerance by the increased activities of defense related system such as ion transport, antioxidant enzymes, proline and MDA content in shoots and roots. The Na+ concentration in the soybean plants was increased in the salt stress; while, bacterial priming significantly reduced the Na+ concentration in the salt stressed soybean plants. However, the antagonistic results were observed for K+ concentration. Additionally, soybean primed with P. pseudoalcaligenes and exposed to 100 mM NaCl showed a new protein band of 28 kDa suggesting that P. pseudoalcaligenes effectively reduced salt stress. Our results showed that salinity tolerance was more pronounced in P. pseudoalcaligenes as compared to B. subtilis. However, a detailed study at molecular level to interpret the mechanism by which P. pseudoalcaligenes alleviates salt stress in soybean plants need to be explored.

Multitrait Pseudomonas spp. Isolated from Monocropped Wheat (Triticum aestivum) Suppress Fusarium Root and Crown Rot.

Fusarium root and crown rot is the most common disease of wheat, especially wheat grown in arid zones where drought is a common issue. The development of environmentally safe approaches to manage diseases of food crops is important for humans. The monocropping system recruits beneficial bacteria that promote plant growth through nutrient solubilization and pathogen suppression. In this study, a field where wheat was monocropped for 5 successive years under rainfed conditions was identified. A total of 29 bacterial isolates were obtained from the rhizosphere, endosphere, and phyllosphere of wheat at its harvesting stage. The Gram-negative bacteria were less prevalent (41%) but the majority (75%) exhibited plant growth-promoting traits. The ability of strains to solubilize nutrients (solubilization index = 2.3 to 4), inhibit pathogenic fungi (25 to 56%), and produce antifungal compounds was highly variable. The rhizobacteria significantly promoted the growth and disease resistance of wheat varieties such as Pirsbak-2015 and Galaxy-2013 by inducing antioxidant enzyme activity (0.2- to 2.1-fold). The bacterial strains were identified as Ochrobactrum spp., Acinetobacter spp., and Pseudomonas mediterranea by 16S rRNA and rpoD sequence analysis. The endophytic bacterium P. mediterranea HU-9 exhibited maximum biocontrol efficacy against wheat root and crown rot diseases with a disease score/disease index from 1.8 to 3.1. The monocropping systems of rainfed agriculture are an ideal source of beneficial bacteria to use as bioinoculants for different crops.

Role of jasmonic acid in improving tolerance of rapeseed (Brassica napus L.) to Cd toxicity.

The well-known detrimental effects of cadmium (Cd) on plants are chloroplast destruction, photosynthetic pigment inhibition, imbalance of essential plant nutrients, and membrane damage. Jasmonic acid (JA) is an alleviator against different stresses such as salinity and drought. However, the functional attributes of JA in plants such as the interactive effects of JA application and Cd on rapeseed in response to heavy metal stress remain unclear. JA at 50 µmol/L was observed in literature to have senescence effects in plants. In the present study, 25 µmol/L JA is observed to be a "stress ameliorating molecule" by improving the tolerance of rapeseed plants to Cd toxicity. JA reduces the Cd uptake in the leaves, thereby reducing membrane damage and malondialdehyde content and increasing the essential nutrient uptake. Furthermore, JA shields the chloroplast against the damaging effects of Cd, thereby increasing gas exchange and photosynthetic pigments. Moreover, JA modulates the antioxidant enzyme activity to strengthen the internal defense system. Our results demonstrate the function of JA in alleviating Cd toxicity and its underlying mechanism. Moreover, JA attenuates the damage of Cd to plants. This study enriches our knowledge regarding the use of and protection provided by JA in Cd stress.

Comparison of Anti-HCV Activity of Multiple Punica granatum Extracts and Fractions in Virus-infected Human Hepatocytes.

BACKGROUND: Plants extracts and their bioactive constituents can provide an alternative approach for new treatment. Pakistani flora reveals a huge, largely untapped source of potential antiviral constituents. OBJECTIVE: High-cost concerns of direct-acting anti-HCV drugs limit their employment specifically in developing countries like Pakistan. Therefore, discovery of inexpensive and nontoxic agents is needed for HCV treatment. METHODOLOGY: In this study, we used plasmid constructs of pCR3.1/FLAGtag/HCV NS3/4A (genotype 1a & 3a) and Punica granatum extracts (PK AV 003) and semi-purified fractions (P1-P11) were evaluated for their anti-HCV activity. Acetone extract along with two fractions (P4 & P11) revealed a useful therapeutic index. RESULTS: The fractions P4 (IC50=28.5±0.02 µg/ml; IC25=16±0.02 µg/ml) and P11 (IC50=72±0.02 µg/ml; IC25=41±0.03 µg/ml) dramatically suppressed HCV replication as measured by quantitative PCR (qPCR) and HCV NS3 protein expression level in transient transfection model. Consistent with suppression in genome replication, inhibition of HCV infectious particles by PK AV 003 extract was also judged in an infectious model system. This data is the first description of Pakistani indigenous cultivated fruit-producing plant, Punica granatum, possessing anti-HCV activity. Further analyses are being performed for investigating the mechanistic studies and structural characterization of purified fractions of PK AV 003. CONCLUSION: Our findings suggest that PK AV 003 fruit extract might be useful as an add-on therapeutic candidate for treating HCV infection.

Bacillus spp., a bio-control agent enhances the activity of antioxidant defense enzymes in rice against Pyricularia oryzae.

Plant growth promoting rhizobacteria (PGPR) are found to control the plant diseases by adopting various mechanisms. Induced systemic resistance (ISR) is an important defensive strategy manifested by plants against numerous pathogens especially infecting at aerial parts. Rhizobacteria elicit ISR by inducing different pathways in plants through production of various metabolites. In the present study, potential of Bacillus spp. KFP-5, KFP-7, KFP-17 was assessed to induce antioxidant enzymes against Pyricularia oryzae infection in rice. The antagonistic Bacillus spp. significantly induced antioxidant defense enzymes i-e superoxide dismutase (1.7-1.9-fold), peroxidase (3.5-4.1-fold), polyphenol oxidase (3.0-3.8-fold), phenylalanine ammonia-lyase (3.9-4.4-fold), in rice leaves and roots under hydroponic and soil conditions respectively. Furthermore, the antagonistic Bacillus spp significantly colonized the rice plants (2.0E+00-9.1E+08) and secreted multiple biocontrol determinants like protease (1.1-5.5 U/mg of soil or U/mL of hydroponic solution), glucanase, (1.0-1.3 U/mg of soil or U/mL of hydroponic solution), siderophores (6.5-42.8 µg/mL or mg) in the rhizosphere of different rice varieties. The results showed that treatment with Bacillus spp. enhanced the antioxidant defense activities in infected rice, thus alleviating P. oryzae induced oxidative damage and suppressing blast disease incidence.

Epidemiological estimates of Respiratory diseases in the hospital population, Faisalabad, Pakistan

ABSTRACT A cross sectional study was conducted in two types of respiratory patients in hospital population. It was found that tuberculosis (T.B) was the most common type (29.66%) followed by the asthma (28.08%) and chronic obstructive pulmonary disease (COPD) (11.31%). Average age of diagnosis was 42.15 ± 0.65 years and average age at present 47.99 ± 0.70 years. Age group 51-60 years was more prone to this disease (21.13%). Most of the patients were married (80.06%). The highest representation of patients with respiratory diseases was observed in 1st birth order (30.36%) followed by 2nd (26.49%) and 3rd (18.45%), while the lowest was in 10th birth order (0.40%). Tuberculosis, asthma and COPD are the most prevalent types of respiratory diseases. Respiratory diseases were more common in males, in first birth order and in people of age group 51-60 years. This disease was more common in married, unemployed, less educated, and lower socioeconomic status people. Socioeconomic status and urban and rural living had a profound effect on the onset of disease.

Comparative transcriptome profiling of two Tibetan wild barley genotypes in responses to low potassium.

Potassium (K) deficiency is one of the major factors affecting crop growth and productivity. Development of low-K tolerant crops is an effective approach to solve the nutritional deficiency in agricultural production. Tibetan annual wild barley is rich in genetic diversity and can grow normally under poor soils, including low-K supply. However, the molecular mechanism about low K tolerance is still poorly understood. In this study, Illumina RNA-Sequencing was performed using two Tibetan wild barley genotypes differing in low K tolerance (XZ153, tolerant and XZ141, sensitive), to determine the genotypic difference in transcriptome profiling. We identified a total of 692 differentially expressed genes (DEGs) in two genotypes at 6 h and 48 h after low-K treatment, including transcription factors, transporters and kinases, oxidative stress and hormone signaling related genes. Meanwhile, 294 low-K tolerant associated DEGs were assigned to transporter and antioxidant activities, stimulus response, and other gene ontology (GO), which were mainly involved in starch and sucrose metabolism, lipid metabolism and ethylene biosynthesis. Finally, a hypothetical model of low-K tolerance mechanism in XZ153 was presented. It may be concluded that wild barley accession XZ153 has a higher capability of K absorption and use efficiency than XZ141 under low K stress. A rapid response to low K stress in XZ153 is attributed to its more K uptake and accumulation in plants, resulting in higher low K tolerance. The ethylene response pathway may account for the genotypic difference in low-K tolerance.

Identification of proteins associated with ion homeostasis and salt tolerance in barley.

Identification and characterization of proteins involved in salt tolerance are imperative for revealing its genetic mechanisms. In this study, ionic and proteomic responses of a Tibetan wild barley XZ16 and a well-known salt-tolerant barley cv. CM72 were analyzed using inductively coupled plasma-optical emission spectrometer, 2DE, and MALDI-TOF/TOF MS techniques to determine salt-induced differences in element and protein profiles between the two genotypes. In total, 41 differentially expressed proteins were identified in roots and leaves, and they were associated with ion homeostasis, cell redox homeostasis, metabolic process, and photosynthesis. Under salinity stress, calmodulin, Na/K transporters, and H(+) -ATPases were involved in establishment of ion homeostasis for barley plants. Moreover, ribulose-1,5-bisphosphate carboxylase/oxygenase activase and oxygen-evolving enhancer proteins were significantly upregulated under salinity stress, indicating the great impact of salinity on photosynthesis. In comparison with CM72, XZ16 had greater relative dry weight and lower Na accumulation in the shoots under salinity stress. A higher expression of HvNHX1 in the roots, and some specific proteins responsible for ion homeostasis and cell redox homeostasis, was also found in XZ16 exposed to salt stress. The current results showed that Tibetan wild barley XZ16 and cultivated barley cultivar CM72 differ in the mechanism of salt tolerance.

Response of seed tocopherols in oilseed rape to nitrogen fertilizer sources and application rates.

Tocopherols (Tocs) are vital scavengers of reactive oxygen species (ROS) and important seed oil quality indicators. Nitrogen (N) is one of the most important fertilizers in promoting biomass and grain yield in crop production. However, the effect of different sources and application rates of N on seed Toc contents in oilseed rape is poorly understood. In this study, pot trials were conducted to evaluate the effect of two sources of N fertilizer (urea and ammonium nitrate). Each source was applied to five oilseed rape genotypes (Zheshuang 72, Jiu-Er-1358, Zheshuang 758, Shiralee, and Pakola) at three different application rates (0.41 g/pot (N1), 0.81 g/pot (N2), and 1.20 g/pot (N3)). Results indicated that urea increased α-, γ-, and total Toc (T-Toc) more than did ammonium nitrate. N3 was proven as the most efficient application rate, which yielded high contents of γ-Toc and T-Toc. Highly significant correlations were observed between Toc isomers, T-Toc, and α-/γ-Toc ratio. These results clearly demonstrate that N sources and application rates significantly affect seed Toc contents in oilseed rape.

Involvement of ethylene in alleviation of Cd toxicity by NaCl in tobacco plants.

The possible involvement of ethylene in alleviating cadmium (Cd) toxicity by NaCl was investigated because our previous experiments showed that a low concentration of NaCl could alleviate Cd toxicity of tobacco plants. Tobacco plants exposed to the treatment of a combination of Cd-NaCl exhibited more vigorous growth than did those exposed to the treatment of Cd stress alone, as reflected by greater biomass, longer roots, taller shoots, larger SPAD values and higher photosynthetic rates. The results also indicated that it is Na(+), rather than Cl(-), that alleviates Cd toxicity. Cd-NaCl treatments enhanced and inhibited ethylene production in roots and in leaves, respectively, in comparison with the plants exposed to Cd alone. However, the exogenous application of ethylene did not improve root growth under Cd exposure, indicating that ethylene is not directly involved in the rooting process. It may be assumed that the addition of NaCl into the solution containing Cd regulates root growth by mediating ethylene synthesis.

Genome-wide association analysis of aluminum tolerance in cultivated and Tibetan wild barley.

Tibetan wild barley (Hordeum vulgare L. ssp. spontaneum), originated and grown in harsh enviroNment in Tibet, is well-known for its rich germpalsm with high tolerance to abiotic stresses. However, the genetic variation and genes involved in Al tolerance are not totally known for the wild barley. In this study, a genome-wide association analysis (GWAS) was performed by using four root parameters related with Al tolerance and 469 DArT markers on 7 chromosomes within or across 110 Tibetan wild accessions and 56 cultivated cultivars. Population structure and cluster analysis revealed that a wide genetic diversity was present in Tibetan wild barley. Linkage disequilibrium (LD) decayed more rapidly in Tibetan wild barley (9.30 cM) than cultivated barley (11.52 cM), indicating that GWAS may provide higher resolution in the Tibetan group. Two novel Tibetan group-specific loci, bpb-9458 and bpb-8524 were identified, which were associated with relative longest root growth (RLRG), located at 2H and 7H on barely genome, and could explain 12.9% and 9.7% of the phenotypic variation, respectively. Moreover, a common locus bpb-6949, localized 0.8 cM away from a candidate gene HvMATE, was detected in both wild and cultivated barleys, and showed significant association with total root growth (TRG). The present study highlights that Tibetan wild barley could provide elite germplasm novel genes for barley Al-tolerant improvement.