Explore the vast range of titles available.

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.

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.

Key messageA 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.

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.

Saline soil is a critical environmental problem affecting crop yield worldwide. Tibetan wild barley is distinguished for its vast genetic diversity and high degree of tolerance to abiotic stress, including salinity. The present study compared the response of antioxidant defense system in the XZ16 wild and CM72 cultivated barleys to salt stress. Wild barley was relatively more tolerant than cultivated CM72, salt-tolerant cultivar, with less Na+ uptake and more K+, Ca2+, and Mg2+ retention in plant tissues. The results of diaminobenzidine (DAB) and nitroblue tetrazolium (NBT) staining showed that XZ16 had significantly lower H2O2 and O2− concentrations than a salt-sensitive cultivar Gairdner, suggesting that the salt-tolerant genotype suffer from less oxidative damage. Moreover, XZ16 and Gairdner had the highest and lowest anti-oxidative enzyme activities and proline content in plant tissues. In addition, the microscopic examination revealed that DNA damage in cv. Gairdner was closely correlated to oxidative stress, representing that more reactive oxygen species accumulation in plants tissues leads to subsequent DNA damage. The present results show that higher salt tolerance of wild barley XZ16 is attributed to less Na+ accumulation and stronger anti-oxidative capacity.

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 (S 6 D 1–105 ) 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.

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.

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.

Covid-19 pandemic forced roughly 1.5 billion learners around the globe (i.e., from early childhood education to university level) to stay at home. Among them, children have been greatly affected by the lockdown and exposed to a diverse range of technological gadgets. Thus, technological gadgets created an engaging space for children to spend their time at home. In the context of Gilgit-Baltistan (GB), Pakistan, this study examines the children’s exposure with technological gadgets and its relationship with gender, age/grade level, and family structure during Covid-19 pandemic lockdown. Through a survey questionnaire, the data were collected from 150 parents. By using Statistical Package for Social Sciences (SPSS 21.0), the data were analyzed. Both the Descriptive (percentages and frequencies) and Inferential (independent t-test and correlation) statistics were applied. The findings of the study revealed that 18% children at informed parents’ program level (i.e., 0-3years), 40% at ECD level (3-8years) and 42% at upper primary level were expose with technological gadgets. However, boys were found to be more exposed with technological gadgets (i.e., 70.7%) as compared to girls (i.e., 28%) during Covid-19 Pandemic Lockdown period in GB. Findings showed that 38% children were found to be in nuclear families, 55% children were in joint and only 6% were in extended families. Mostly children use mobile and laptop/ computers (39.3%) whereas only 16.7% children use TV in Gilgit.  It was also revealed that 58.7% parents supervise while 41.3% parents does not supervise their children while using technological gadgets. However, there was no significant difference between male and female children across age group. The study recommended to carry out a research study in the future to investigate the family structure and use of technological devices by increasing the sample size and research sites to get more insights.  

Lentil is an important legume crop globally with an annual production of around 6.3 million tons. Pakistan stands at the 49th position producing 4668 tons of lentil from 7428 hectares with an average yield of 570 kg/ha. A lack of high-yielding varieties is one of the major reasons for low yield, resulting in an approx. 31% decrease in the cultivation area. In the present study, 649 accessions of lentil representing Pakistan, USA, and Syria were studied for yield and yield-contributing traits for three consecutive years. Accession 5930 performed best in all three years, having a seed yield (SY) of 192.84 ± 9.05 g/m2 and a biological yield (BY) of 534.20 ± 25.79 g/m2. Overall, SY has a significant positive association with BY, pods per plant (NP), pod weight (PW), harvest index (HI), and plant height (PH). PCA, heritability, and genetic advance also suggested these traits as effective selection indicators. A K-mean cluster analysis based on Wilks lambda highlighted that accessions with a higher SY, BY, NP, PW, and NB were grouped in Clusters III, V, and II during the first, second, and third years, respectively. During all three years, genotypes in the HI range 10.1–15% had the highest biological yield, while the HI range of >35% represented early maturing accessions with high seed yields, providing a strong basis for future selection. Fluctuation in mean temperature (22.5, 22.4 and 24.7 °C) and rainfall (518, 644.6 and 287.7 mm) during the three cropping seasons (October–April) under study had a significant impact on performance of the accessions. The better average yield was observed in the third year, which might be attributed to aforementioned temperature and rainfall differences. Despite the weather impact, 10 accessions, viz., 5930, 6057, 5865, 34709, 5542, 5884, 17794, 34693, 5888, and 5944 exhibited high yield potential in all three years and are therefore recommended for lentil improvement programs in the future.