Ameliorating heat stressed conditions in wheat by altering its physiological and phenotypic traits associated with varying nitrogen levels

Currently, more than half of the global nations cultivating wheat crops are facing severe consequences of climate change and its associated heat stress in terms of quantitative and qualitative yield losses. Plants exposed to heat stress need a balanced and adequate amount of mineral nutrients to counter its ill effects. Therefore, the present study was designed to investigate the potential effects of heat stress applied during the vegetative growth period (Zadoks growth scale: ZGS 5-60) on physiological and phenotypic traits of wheat (Triticum aestivum) crop subjected to variable rates of nitrogen (N). In this experiment, wheat plants of cv. ‘Punjab-2011’ were exposed to two levels of temperature i.e. heat stress (HS) and control or non-heat stress (NHS), and three N rates (N50 = 50 kg ha-1, N100= 100 kg ha-1 and N150 = 150 kg ha-1). The experiment was executed under controlled conditions in a completely randomized design (CRD) with six replications. One set of eighteen pots containing wheat seedlings was placed in a compartment of the greenhouse under heat-stressed conditions, while another set was placed in another compartment under non-heated conditions. The greenhouse compartments were equipped with a heating and cooling system to maintain desired ecological conditions. Pots in heated chamber were kept for 60 days from emergence (ZGS = 5-60), and then shifted to non-heated chamber till harvesting. The temperature in heat stress treatment was almost 2 ± 0.47 °C higher than in non-heated treatment. The results indicated that HS significantly reduced the photosynthetic rate by 42.52%, leaf photosynthetic efficiency by 56.82%, chlorophyll scores by 20.11%, relative water contents (RWC) by 12.81%, tillers by 48.21%, grain weight by 21.47% and grain yield by 68.20% relative to NHS conditions. These reductions were more prominent in plants subjected to a limited N dose rate (50 kg N ha-1). Furthermore, the results also revealed higher transpiration rate, stomatal conductance, and membrane ruptures under HS with N50 treatment.  However, N150 treatment compensated for the detrimental effects of HS on wheat plants by improving the photosynthetic rate and efficiencies, higher RWC, more stability of membrane and pigments, more tillers, and higher grain weight, and grain yield of wheat. Additionally, grain yield was negatively correlated with transpiration rate, stomatal conductance, internal CO2 concentration, and membrane leakage. In conclusion, a high dose rate of N under high temperatures during vegetative growth could alleviate the magnitude of penalties to grain yield and enhance the potential of wheat crops to withstand heat-induced detrimental effects

Enhancing crop resilience through thiamine: implications for sustainable agriculture in drought-stressed radish

During 21st century, abiotic stress has adversely affected the agriculture crop production around the globe. Keeping in view the food requirement under water shortage condition, a study was planned to investigate the effect of thiamine application on radish crop under drought stress conditions on plant. For study purpose, two varieties of locally available radish (‘Early-Milo’ and ‘Laal-Pari’) were grown with normal water application as well as thiamine (100 mg L-1) application while maintaining a stress condition (60% field capacity). Increasing water deficit stress linearly reduced plant growth, yield and biomass in both varieties by reducing water use efficiency, while significantly enhanced these attributes with thiamine application. Thiamine application under drought stress exerted significant impacts on physiological attributes in both varieties, including enhanced osmolytic attribute in drought conditions and improvements in superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), H2O2, and malondialdehyde (MDA) activities in plant leaves. Antioxidant and osmoprotectant upregulation positively linked to radish crop's drought tolerance. Moreover, PCA and heatmap analysis revealed a significant interdependence among various traits and interconnected in determining the crop's capacity to sustain growth under conditions of drought stress. In crux, thiamine application conclusively enhances radish growth, yield, biomass, physio-chemical and osmolytic attributes, ionic composition and enzymatic antioxidant potential. Therefore, it is recommended to consider the application of thiamine in commercial agriculture practices to mitigate the negative effects of drought stress on radish crop production

Remediation of wastewater by biosynthesized manganese oxide nanoparticles and its effects on development of wheat seedlings

IntroductionNanoparticles play a vital role in environmental remediation on a global scale. In recent years, there has been an increasing demand to utilize nanoparticles in wastewater treatment due to their remarkable physiochemical properties.MethodsIn the current study, manganese oxide nanoparticles (MnO-NPs) were synthesized from the Bacillus flexus strain and characterized by UV/Vis spectroscopy, X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy.ResultsThe objective of this study was to evaluate the potential of biosynthesized MnO-NPs to treat wastewater. Results showed the photocatalytic degradation and adsorption potential of MnO-NPs for chemical oxygen demand, sulfate, and phosphate were 79%, 64%, and 64.5%, respectively, depicting the potential of MnO-NPs to effectively reduce pollutants in wastewater. The treated wastewater was further utilized for the cultivation of wheat seedlings through a pot experiment. It was observed that the application of treated wastewater showed a significant increase in growth, physiological, and antioxidant attributes. However, the application of treated wastewater led to a significant decrease in oxidative stress by 40%.DiscussionIt can be concluded that the application of MnO-NPs is a promising choice to treat wastewater as it has the potential to enhance the growth, physiological, and antioxidant activities of wheat seedlings

A source of resistance against yellow mosaic disease in soybeans correlates with a novel mutation in a resistance gene

Yellow mosaic disease (YMD) is one of the major devastating constraints to soybean production in Pakistan. In the present study, we report the identification of resistant soybean germplasm and a novel mutation linked with disease susceptibility. Diverse soybean germplasm were screened to identify YMD-resistant lines under natural field conditions during 2016-2020. The severity of YMD was recorded based on symptoms and was grouped according to the disease rating scale, which ranges from 0 to 5, and named as highly resistant (HR), moderately resistant (MR), resistant (R), susceptible (S), moderately susceptible (MS), and highly susceptible (HS), respectively. A HR plant named “NBG-SG Soybean” was identified, which showed stable resistance for 5 years (2016-2020) at the experimental field of the National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan, a location that is a hot spot area for virus infection. HS soybean germplasm were also identified as NBG-47 (PI628963), NBG-117 (PI548655), SPS-C1 (PI553045), SPS-C9 (PI639187), and cv. NARC-2021. The YMD adversely affected the yield and a significant difference was found in the potential yield of NBG-SG-soybean (3.46 ± 0.13a t/ha) with HS soybean germplasm NARC-2021 (0.44 ± 0.01c t/ha) and NBG-117 (1.12 ± 0.01d t/ha), respectively. The YMD incidence was also measured each year (2016-2020) and data showed a significant difference in the percent disease incidence in the year 2016 and 2018 and a decrease after 2019 when resistant lines were planted. The resistance in NBG-SG soybean was further confirmed by testing for an already known mutation (SNP at 149th position) for YMD in the Glyma.18G025100 gene of soybean. The susceptible soybean germplasm in the field was found positive for the said mutation. Moreover, an ortholog of the CYR-1 viral resistance gene from black gram was identified in soybean as Glyma.13G194500, which has a novel deletion (28bp/90bp) in the 5`UTR of susceptible germplasm. The characterized soybean lines from this study will assist in starting soybean breeding programs for YMD resistance. This is the first study regarding screening and molecular analysis of soybean germplasm for YMD resistance

Exploitation of mangliculous marine fungi, Amarenographium solium, for the green synthesis of silver nanoparticles and their activity against multiple drug-resistant bacteria

The green synthesis pathway for silver nanoparticles (AgNPs) used in bacterial treatment is regarded as crucial because of its cost-effectiveness, nontoxicity, and eco-friendliness. During the present work, the mangliculous marine fungi Amarenographium solium isolated from the Arabian Gulf Coast of Saudi Arabia were utilized for the synthesis of AgNP, through the bio-reduction of aqueous silver nitrate (AgNO3) solution. The success in AgNP synthesis was visually identified by the development of dark brown color in the cell-free filtrate and was further confirmed by ultraviolet–visible spectroscopy, which showed a peak at 425 nm. The AgNPs produced were further characterized using X-ray diffraction data analysis that proved the bioreduction of silver to 20 nm, and transmission electron microscopy revealed the formation of well-dispersed spherical nanoparticles with an average mean size of 12 nm. The optimization reaction parameters of temperature, pH, and metal salt concentration were carried out and resulted in a combination of 30°C, 7 and 1.5 mM, respectively, for rapid and maximum yield production. The antibacterial activity of the produced nanoparticles was evaluated using the two-fold microdilution method and showed a minimum inhibitory concentration of 9.375 μg/mL of AgNP against multiple drug-resistant bacterial strains

Microbial dynamics and dehydrogenase activity in tomato (Lycopersicon esculentum Mill.) rhizospheres: Impacts on growth and soil health across different soil types

The dehydrogenase activity (DHA) in the rhizospheres of tomatoes grown in different soil types – Khor Abu-Habil (KA), Bara (B), and Greenhouse (Gr) – in North Kordofan, Sudan, was determined. In addition, the abundance of soil microbes in the tomato rhizospheres during the two growth stages, after 45 and 90 days (short and long term), was analyzed. The KA site (clay soil) showed the highest DHA (81.79 CFUs/g) followed by the B site (63.76 CFUs/g) (sandy loam) after 90 days of sowing, and the Gr site showed the lowest DHA (44.50 CFUs/g) (loamy sand soil) after 45 days. Moreover, the presence of high microbial activity (total density counts, total fungi, phosphate-solubilizing bacteria, Streptomycetes sp., Azotobacter sp., Azospirillum sp., and Pseudomonas sp. density counts) after 90 days and minimum microbial abundance after 45 days were identified at all sites. The measured growth parameters of fresh and dry weight, in addition to the root-to-shoot ratio, increased significantly at the same KA site dominated by a higher microbial density after 90 days. During the long term, the growth stage was positively affected by the abundance of adapted microbials that improve and enhance plant growth

Metal-tolerant morganella morganii isolates can potentially mediate nickel stress tolerance in Arabidopsis by upregulating antioxidative enzyme activities

Plant growth-promoting rhizobacteria (PGPRs) have been utilized to immobilize heavy metals, limiting their translocation in metal contaminated settings. However, studies on the mechanisms and interactions that elucidate how PGPRs mediate Nickel (Ni) tolerance in plants are rare. Thus, in this study we investigated how two pre-characterized heavy metal tolerant isolates of Morganella morganii (ABT9 and ABT3) improve Ni stress tolerance in Arabidopsis while enhancing its growth and yield. Arabidopsis seedlings were grown for five weeks in control/Ni contaminated (control, 1.5 mM and 2.5 mM) potted soil, in the presence or absence of PGPRs. Plant growth characteristics, quantum yield, and antioxidative enzymatic activities were analyzed to assess the influence of PGPRs on plant physiology. Oxidative stress tolerance was quantified by measuring MDA accumulation in Arabidopsis plants. As expected, Ni stress substantially reduced plant growth (shoot and root fresh weight by 53.25% and 58.77%, dry weight by 49.80% and 57.41% and length by 47.16% and 64.63% over control), chlorophyll content and quantum yield (by 40.21% and 54.37% over control). It also increased MDA content by 84.28% at higher (2.5 mM) Ni concentrations. In contrast, inoculation with M. morganii led to significant improvements in leaf chlorophyll, quantum yield, and Arabidopsis biomass production. The mitigation of adverse effects of Ni stress on biomass observed in M. morganii-inoculated plants was attributed to the enhancement of antioxidative enzyme activities compared to Ni-treated plants. This upregulation of the antioxidative defense mechanism mitigated Ni-induced oxidative stress, leading to improved performance of the photosynthetic machinery, which, in turn, enhanced chlorophyll content and quantum yield. Understanding the underlying mechanisms of these tolerance-inducing processes will help to complete the picture of PGPRs-mediated defense signaling. Thus, it suggests that M. morganii PGPRs candidate can potentially be utilized for plant growth promotion by reducing oxidative stress via upregulating antioxidant defense systems in Ni-contaminated soils and reducing Ni metal uptake

Novel Copper Oxide Phyto-Nanocatalyst Utilized for the Synthesis of Sustainable Biodiesel from <i>Citrullus colocynthis</i> Seed Oil

The green chemistry method for nanocatalyst synthesis along with environmentally feasible non-edible sources are promising alternatives to fossil fuels. The current study focuses on the synthesis of copper oxide phyto-nanocatalyst and the identification of a new renewable feedstock, Citrullus colocynthis, to reduce environmental pollution. The highest biodiesel yield (95%) was obtained under optimum conditions of a 1:8 oil-to-methanol ratio and reaction temperature of 85 °C for 120 min with a 0.365 wt% catalyst concentration. The phyto-nanocatalyst was synthesized using seed oil cake after extracting oil with the salt of copper (copper oxide). The catalyst was then subjected to various analyses, namely, EDX, FT-IR, SEM, and XRD. The catalyst was proved to be efficient and effective after being reused five times and still there was a very small difference in biodiesel yield. All the analyses also show sustainable and stable results. Thus, copper oxide phyto-nanocatalyst with non-edible Citrullus colocynthis proved to be highly effective, sustainable, and a better alternative source to the future biodiesel industry

Table_1_A source of resistance against yellow mosaic disease in soybeans correlates with a novel mutation in a resistance gene.docx

Yellow mosaic disease (YMD) is one of the major devastating constraints to soybean production in Pakistan. In the present study, we report the identification of resistant soybean germplasm and a novel mutation linked with disease susceptibility. Diverse soybean germplasm were screened to identify YMD-resistant lines under natural field conditions during 2016-2020. The severity of YMD was recorded based on symptoms and was grouped according to the disease rating scale, which ranges from 0 to 5, and named as highly resistant (HR), moderately resistant (MR), resistant (R), susceptible (S), moderately susceptible (MS), and highly susceptible (HS), respectively. A HR plant named “NBG-SG Soybean” was identified, which showed stable resistance for 5 years (2016-2020) at the experimental field of the National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan, a location that is a hot spot area for virus infection. HS soybean germplasm were also identified as NBG-47 (PI628963), NBG-117 (PI548655), SPS-C1 (PI553045), SPS-C9 (PI639187), and cv. NARC-2021. The YMD adversely affected the yield and a significant difference was found in the potential yield of NBG-SG-soybean (3.46 ± 0.13a t/ha) with HS soybean germplasm NARC-2021 (0.44 ± 0.01c t/ha) and NBG-117 (1.12 ± 0.01d t/ha), respectively. The YMD incidence was also measured each year (2016-2020) and data showed a significant difference in the percent disease incidence in the year 2016 and 2018 and a decrease after 2019 when resistant lines were planted. The resistance in NBG-SG soybean was further confirmed by testing for an already known mutation (SNP at 149th position) for YMD in the Glyma.18G025100 gene of soybean. The susceptible soybean germplasm in the field was found positive for the said mutation. Moreover, an ortholog of the CYR-1 viral resistance gene from black gram was identified in soybean as Glyma.13G194500, which has a novel deletion (28bp/90bp) in the 5`UTR of susceptible germplasm. The characterized soybean lines from this study will assist in starting soybean breeding programs for YMD resistance. This is the first study regarding screening and molecular analysis of soybean germplasm for YMD resistance.</p