Application of CuNPs and AMF alleviates arsenic stress by encompassing reduced arsenic uptake through metabolomics and ionomics alterations in Elymus sibiricus.

Recent studies have exhibited a very promising role of copper nanoparticles (CuNPs) in mitigation of abiotic stresses in plants. Arbuscular mycorrhizae fungi (AMF) assisted plants to trigger their defense mechanism against abiotic stresses. Arsenic (As) is a non-essential and injurious heavy-metal contaminant. Current research work was designed to elucidate role of CuNPs (100, 200 and 300 mM) and a commercial inoculum of Glomus species (Clonex® Root Maximizer) either alone or in combination (CuNPs + Clonex) on physiology, growth, and stress alleviation mechanisms of E. sibiricus growing in As spiked soils (0, 50, and 100 mg Kg- 1 soil). Arsenic induced oxidative stress, enhanced biosynthesis of hydrogen peroxide, lipid peroxidation and methylglyoxal (MG) in E. sibiricus. Moreover, As-phytotoxicity reduced photosynthetic activities and growth of plants. Results showed that individual and combined treatments, CuNPs (100 mM) as well as soil inoculation of AMF significantly enhanced root growth and shoot growth by declining As content in root tissues and shoot tissues in As polluted soils. E. sibiricus plants treated with CuNPs (100 mM) and/or AMF alleviated As induced phytotoxicity through upregulating the activity of antioxidative enzymes such as catalase (CAT) and superoxide dismutase (SOD) besides the biosynthesis of non-enzymatic antioxidants including phytochelatin (PC) and glutathione (GSH). In brief, supplementation of CuNPs (100 mM) alone or in combination with AMF reduced As uptake and alleviated the As-phytotoxicity in E. sibiricus by inducing stress tolerance mechanism resulting in the improvement of the plant growth parameters.

FeONPs alleviate cadmium toxicity in Solanum melongena through improved morpho-anatomical and physiological attributes, along with oxidative stress and antioxidant defense regulations.

In this study, various constraints of Cd toxicity on growth, morpho-anatomical characters along with physiological and biochemical metabolic processes of Solanum melongena L. plants were analyzed. Conversely, ameliorative role of iron oxide nanoparticles (FeONPs) was examined against Cd stress. For this purpose, the following treatments were applied in completely randomized fashion; 3 mM CdCl2 solution applied with irrigation water, 40 and 80 ppm solutions of FeONPs applied via foliar spray. Regarding the results, Cd caused oxidative damage to plants' photosynthetic machinery, resulting in elevated levels of stress-markers like malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolytic leakage (EL) along with slight increase in antioxidants activities, including glutathione (GsH), ascorbate (AsA), catalases (CAT), peroxidases (POD), superoxide dismutase (SOD), and ascorbate peroxidases (APX). Also, high Cd level in plants disturb ions homeostasis and reduced essential minerals uptake, including Ca and K. This ultimately reduced growth and development of S. melongena plants. In contrast, FeONPs supplementations improved antioxidants (enzymatic and non-enzymatic) defenses which in turn limited ROS generation and lowered the oxidative damage to photosynthetic machinery. Furthermore, it maintained ionic balance resulting in enhanced uptake of Ca and K nutrients which are necessary for photosynthesis, hence also improved photosynthesis rate of S. melongena plants. Overall, FeONPs foliar spray effectively mitigated Cd toxicity imposed on S. melongena plants.

Comparative mineral and biochemical characterization of Citrus reticulata fruits and leaves to citrus canker pathogens, Xanthomonas axonopodis.

Pakistan's economy greatly benefits from citrus production since these fruits are sold and consumed all over the world. Although citrus fruits are easy to cultivate, they are susceptible to diseases caused by bacteria, viruses, and fungi. These challenges, as well as difficulties in obtaining the proper nutrients, might negatively impact fruit yields and quality. Citrus canker is another complicated problem caused by the germ Xanthomonas axonopodis. This germ affects many types of citrus fruits all over the world. This study looked closely at how citrus canker affects the leaves and the quality of the fruit in places like Sargodha, Bhalwal, Kotmomin, and Silanwali, which are big areas for growing citrus in the Sargodha district. What we found was that plants without the disease had more chlorophyll in their leaves compared to the sick plants. Also, the healthy plants had better amounts of important minerals like calcium, magnesium, potassium, and phosphorus in their fruits. But the fruits with the disease had too much sodium, and the iron levels were a bit different. The fruits with the disease also didn't have as much of something that protects them called antioxidants, which made them more likely to get sick. This study helps us understand how citrus canker affects plants and fruit, so we can think of ways to deal with it.

The Glycine soja cytochrome P450 gene GsCYP82C4 confers alkaline tolerance by promoting reactive oxygen species scavenging.

Recent studies have demonstrated the crucial role of Cytochrome P450 enzymes (CYPs) in the production of secondary metabolites, phytohormones and antioxidants in plants. However, their functional characterization specifically under alkaline stress remains elusive. CYP82C4 was the key gene screened from a family of wild soybean CYPs in our previous studies. The aim of this present study was to clone the Glycine soja GsCYP82C4 gene and characterize its functions in Arabidopsis and Glycine max. The results showed that the GsCYP82C4 gene displayed a high expression in different plant tissues at mature stages compared to young stages. Further, higher temporal expression of the GsCYP82C4 gene was noted at 6, 12 and 24 h time points after alkali treatment in leaves compared to roots. In addition, overexpression of GsCYP82C4 improved alkaline stress tolerance in Arabidopsis via increased root lengths and fresh biomass and strengthened the antioxidant defense system via a reduction in superoxide radicals in transgenic lines compared to wild type (WT) and atcyp82c4 mutants. Further, the expression levels of stress-related marker genes were up-regulated in GsCYP82C4 OX lines under alkali stress. The functional analysis of GsCYP82C4 overexpression in soybean displayed better hairy root growth, increased fresh weight, higher antioxidant enzyme activities and reduced lipid peroxidation rates in OX lines compared to the soybean WT (K599) line. In total, our study displayed positive roles of GsCYP82C4 overexpression in both Arabidopsis and Glycine max to alleviate alkaline stress via altering expression abundance of stress responsive genes, stronger roots, higher antioxidant enzyme activities as well as reduced rates of lipid peroxidation and superoxide radicals.

Maize/peanut rotation intercropping improves ecosystem carbon budget and economic benefits in the dry farming regions of China.

Monoculture is widely practiced to increase crop productivity, but long-term adaptation has drawbacks as it increases the depletion of soil nutrients and reduces soil quality, especially in dryland areas. Conversion from traditional maize monoculture to intercropping improves sustainable production. However, maize/peanut intercropping, especially rotation of planting strips impacts of maize/peanut intercropping in dryland on carbon (C) budgets and economic benefits remain unclear. In this study, a 5-year field experiment was conducted to evaluate the influence of maize/peanut intercropping with rotation of planting strips on soil health, indirect CO2-eq greenhouse gas emissions, and ecosystem C inputs. Four intercropping treatments viz. maize monoculture, peanut monoculture, maize/peanut intercropping, and maize/peanut rotation-intercropping were tested from 2018 to 2022. Maize/peanut rotation intercropping significantly improved the land equivalent ratio followed by intercropping and monoculture. Rotation-intercropping also improved economic benefits over intercropping and monoculture which were mainly associated with increased peanut yield where the border rows contributed the maximum, followed by the middle rows. Moreover, rotation-intercropping significantly increased the soil organic C and nitrogen (N) content. Rotation-intercropping decreased indirect CO2-eq greenhouse gas emissions and ecosystem C inputs by 3.11% and 18.04%, whereas increased ecosystem C outputs and net ecosystem C budget by 10.38% and 29.14%, respectively, over the average of monoculture. On average for intercropping and monoculture, rotation-intercropping increased ecosystem C emission efficiency for economic benefits by 51.94% and 227.27% in 2021 and 2022, respectively, showing the highest C utilization efficiency than other treatments. In the long run, maize/peanut rotation-intercropping can be practiced in dryland agriculture to achieve sustainable agriculture goals.

Synergistic soil-less medium for enhanced yield of crops: a step towards incorporating genomic tools for attaining net zero hunger.

Globally, industrial farming endangers crucial ecological mechanisms upon which food production relies, while 815 million people are undernourished and a significant number are malnourished. Zero Hunger aims to concurrently solve global ecological sustainability and food security concerns. Recent breakthroughs in molecular tools and approaches have allowed scientists to detect and comprehend the nature and structure of agro-biodiversity at the molecular and genetic levels, providing us an advantage over traditional methods of crop breeding. These bioinformatics techniques let us optimize our target plants for our soil-less medium and vice versa. Most of the soil-borne and seed-borne diseases are the outcomes of non-treated seed and growth media, which are important factors in low productivity. The farmers do not consider these issues, thereby facing problems growing healthy crops and suffering economic losses. This study is going to help the farmers increase their eco-friendly, chemical residue-free, quality yield of crops and their economic returns. The present invention discloses a synergistic soil-less medium that consists of only four ingredients mixed in optimal ratios by weight: vermicompost (70-80%), vermiculite (10-15%), coco peat (10-15%), and Rhizobium (0-1%). The medium exhibits better physical and chemical characteristics than existing conventional media. The vermiculite to coco peat ratio is reduced, while the vermicompost ratio is increased, with the goals of lowering toxicity, increasing plant and water holding capacity, avoiding drying of the media, and conserving water. The medium provides balanced nutrition and proper ventilation for seed germination and the growth of seedlings. Rhizobium is also used to treat the plastic bags and seeds. The results clearly show that the current synergistic soil-less environment is best for complete plant growth. Securing genetic advantages via sexual recombination, induced random mutations, and transgenic techniques have been essential for the development of improved agricultural varieties. The recent availability of targeted genome-editing technology provides a new path for integrating beneficial genetic modifications into the most significant agricultural species on the planet. Clustered regularly interspaced short palindromic repeats and associated protein 9 (CRISPR/Cas9) has evolved into a potent genome-editing tool for imparting genetic modifications to crop species. In addition, the integration of analytical methods like population genomics, phylogenomics, and metagenomics addresses conservation problems, while whole genome sequencing has opened up a new dimension for explaining the genome architecture and its interactions with other species. The in silico genomic and proteomic investigation was also conducted to forecast future investigations for the growth of French beans on a synergistic soil-less medium with the purpose of studying how a blend of vermicompost, vermiculite, cocopeat, and Rhizobium secrete metal ions, and other chemical compounds into the soil-less medium and affect the development of our target plant as well as several other plants. This interaction was studied using functional and conserved region analysis, phylogenetic analysis, and docking tools.

Host-mediated gene engineering and microbiome-based technology optimization for sustainable agriculture and environment.

The agricultural sector and environmental safety both work hand in hand to promote sustainability in important issues like soil health, plant nutrition, food safety, and security. The conventional methods have greatly harmed the environment and people's health and caused soil fertility and quality to decline as well as deteriorate. Keeping in view the excessive exploitation and cascade of degradation events due to unsustainable farming practices, the need of the hour demands choosing an appropriate, eco-friendly strategy to restore soil health, plant nutrition, and environmental aspects. The priority highlights a need for a sustainable and environment-friendly upgradation of the present agricultural systems to utilize the beneficial aspects related to harnessing the gene-microbiome strategies which would help in the restoration and replenishment of the microbial pool. Thus, exploring the microbiome is the utmost priority which gives a deep insight into the different aspects related to soil and plant and stands out as an important contributor to plant health and productivity. "Microbes" are important drivers for the biogeochemical cycles and targets like sustainability and safety. This essential microbial bulk (soil microbiome) is greatly influenced by agricultural/farming practices. Therefore, with the help of microbiome engineering technologies like meta-transcriptomics, meta-proteomics, metabolomics, and novel gene-altering techniques, we can easily screen out the highly diverse and balanced microbial population in the bulk of soil, enhancing the soil's health and productivity. Importantly, we need to change our cultivation strategies to attain such sustainability. There is an urgent need to revert to natural/organic systems of cultivation patterns where the microbiome hub can be properly utilized to strengthen soil health, decrease insect pest and disease incidence, reduce greenhouse gas emissions, and ultimately prevent environmental degradation. Through this article, we wish to propose a shift in the cultivation pattern from chemical to the novel, upgraded gene-assisted designed eco-friendly methodologies which can help in incorporating, exploring, and harnessing the right microbiome consortium and can further help in the progression of environmentally friendly microbiome technologies for agricultural safety and productivity.

Triticum aestivum: antioxidant gene profiling and morpho-physiological studies under salt stress.

BACKGROUND: Soil salinity drastically reduced wheat growth and production in Pakistan. It is a need of an hour to identify the best suitable salt tolerance or resistant wheat varieties which shows good growth under salinity affected areas. In presented study, two wheat varieties Johar (salt tolerant) and Sarsabaz (salt sensitive) were examined under NaCl stress conditions. METHODS: Antioxidant enzyme activities were investigated in 10-days old wheat seedlings under 200 mM NaCl stress in hydroponic conditions. To investigate the various growth parameters, antioxidant enzyme activities such as superoxide dismutase (SOD: EC 1.15.1.1), catalase (CAT: EC 1.11.1.6) and ascorbate peroxidase (APX: EC 1.11.1.11) were monitored and studied. Besides this various growth parameters such as length of the roots, shoots, as well as Physiological parameters likes lipid peroxidation by malondialdehyde (MDA), hydrogen peroxide (H2O2), and proline contents and antioxidant enzyme activities were estimated. The effect of salinity was also observed on gene transcription level and eventually expression level. RESULTS: Shoot and root length were decreased in Sarsabaz variety while it showed opposite trend in johar at 200 mM salt concentration. The concentration of proline showed a noticeable rise in salt dependency. Higher concentrations of Proline in Johar were observed as compared to Sarsabaz. SOD showed the increase in activity for antioxidant enzymes. Significant increase of SOD levels were observed in shoot tissues as compared to root tissues. The results indicated that the shoots were more susceptible to salt stress. Activity of APX showed similar affects in both varieties. The production of CAT enzyme in the shoot and root tissues of both varieties showed substantial growth under increased salt stress. Furthermore, NaCl stress has increased the expression of certain genes coding for antioxidant enzymes such as catalase, superoxide dismutase, and peroxidase. Maximum expression of all the antioxidant enzyme coding genes were observed in Johar (tolerant) at 48 h exposure to salt. In contrast the expression of the all mentioned genes in Sarsabaz variety were found maximum at early hours (24 h) and gradually decreased at 48 h. CONCLUSION: The study showed that the selected salt tolerant wheat variety Johar is significantly resistant to 200 mM NaCl salt level as compared to Sarsabaz.

Mitigation of chromium-induced phytotoxicity in 28-homobrassinolide treated Trigonella corniculata L. by modulation of oxidative biomarkers and antioxidant system.

Chromium (Cr) is one of the toxic heavy metals that disturbs growth and physiological properties of plants. During the current study, Trigonella corniculata L. (Fenugreek) was exposed to different levels of Cr in potted soil. Chromium toxicity reduced fiber, ash, moisture, carbohydrate, protein, fats, and flavonoid content of T. corniculata. Considering the stress relieving effect of 28-homobrassinolide (28-HBR), seeds of T. corniculata were primed with different concentration of 28-HBR i.e., 0, 5, 10, and 20 µmol L-1. Application of 28-HBR reversed the toxic effect of Cr through improvement in activity of antioxidant enzymes like superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT). Conclusively, 10 µmol L-1 28-HBR increased Cr tolerance in T. corniculata seedlings due to reduction in oxidative stress markers. It is further proposed that 28-HBR is an effective stress ameliorant to relive plants from various abiotic stresses.

Enhancing drought stress tolerance in Camelina (Camelina sativa L.) through exogenous application of potassium.

The current study was performed under controlled conditions to study the effects of exogenous potassium application on carotenoid contents and drought tolerance in Camelina. Water deficit levels such as 100% FC (control) and 40% FC (drought stress) were imposed after germination of Camelina plants grown to maturity, and different treatments of exogenous K+ were applied at the vegetative stage. We have reported 17 traits of plant growth, physiology, antioxidant enzyme activity, focusing on carotenoids in Camelina to explore their potential yield and yield components. For this purpose, we used multivariate analysis techniques (descriptive statistics, correlation matrix, analysis of variance [ANOVA] and principal components analysis [PCA] to determine the best relation between potassium and studied traits). The results showed a large number of variations in the studied trait under control and water deficit condition. Plant fresh weight (g) was negatively correlated with shoot length and SOD insignificantly correlated with plant fresh weight (g) under water deficit conditions. Potassium loading predicted that foliar application (3 mM K2 SO4 ), foliar application (6 mM KNO3 ), foliar application (12 mM KNO3 ) and foliar application (12 mM K2 SO4 ) are the important doses that contribute the most to enhance the growth, physiological and biochemical activities and carotenoids to improve the Camelina yield under water deficit condition. These doses should be considered in the future to improve the Camelina yield under semi-arid conditions with increased genetic diversity (varietal selection).

MiRNA fine tuning for crop improvement: using advance computational models and biotechnological tools.

MiRNAs modulate target genes expression at post-transcriptional levels, by reducing spatial abundance of mRNAs. MiRNAs regulats plant metabolism, and emerged as regulators of plant stress responses. Which make miRNAs promising candidates for fine tuning to affectively alter crop stress tolerance and other important traits. With recent advancements in the computational biology and biotechnology miRNAs structure and target prediction is possible resulting in pin point editing; miRNA modulation can be done by up or down regulating miRNAs using recently available biotechnological tools (CRISPR Cas9, TALENS and RNAi). In this review we have focused on miRNA biogenesis, miRNA roles in plant development, plant stress responses and roles in signaling pathways. Additionally we have discussed latest computational prediction models for miRNA to target gene interaction and biotechnological systems used recently for miRNA modulation. We have also highlighted setbacks and limitations in the way of miRNA modulation; providing entirely a new direction for improvement in plant genomics primarily focusing miRNAs.

Study of genetic modifications of flower development and methylation status in phytoplasma infected Brassica (Brassica rapa L.).

BACKGROUND: The plants of B. rapa (syn. B. campestris) are the most important food crop of Pakistan for the production of cooking oil. Brassica plants infected by phytoplasma exhibit floral abnormalities including phyllody, virescence, hypertrophied sepal and aborted reproductive organs and affected flower developmental genes which reduces the yield manifold. METHODS AND RESULTS: The expression level of flower developmental genes in healthy and phytoplasma infected brassica were compared by using semi-quantitative reverse transcription polymerase chain reaction and DNA hybridization. In infected brassica, LEAFY (LFY) gene, controlling the development and maintenance of floral organ, and directly involved in controlling the homeotic gene expression was affected, while APETALA2, regulate the production of sepals and petals, were not altered. Whereas the genes WUSCHEL, APETALA3 and AGAMOUS, were significantly down-regulated, that were responsible for the identity of shoot and central meristem, petals and stamens production, and stamens and carpels development, respectively. The GLUB gene, controlling the production of ß-1,3-glucanases enzyme, was highly up-regulated. According to DNA hybridization results, AGAMOUS and APETALA3 were restricted to floral organs territories in healthy and phytoplasma infected brassica, indicating that their expression was tissue-specific. These outcomes indicated that flower abnormalities of phytoplasma infected B. rapa are linked with DNA methylation in the expression of homeotic genes regulating flower development. CONCLUSIONS: Azacitidine act as a DNA demethylating reagent. By applying the foliar spray of azacitidine during the flower development, cells of Phytoplasma infected plants exhibits demethylation of DNA when treated with azacitidine chemical that incorporated as analogue of cytosine during the cell division stage. B. rapa showed the up-regulation of gene expression level significantly that restore the normal production of flowers, ultimately increase the oil production throughout the world.

Regulatory role of folic acid in biomass production and physiological activities of Coriandrum sativum L. under irrigation regimes.

Water deficiency represents the major cause that affects agricultural output globally. A water-saving strategy was introduced by using water deficit conditions and growth regulators. Foliar application of folic acid (FA) has been found suitable not only for drought stress alleviation in Coriandrum. sativum but also beneficial for improvement in growth and yield under water deficit circumstances. The current study examined the potential roles of FA under drought to improve C. sativum growth. The C. sativum variety was subjected to three levels of irrigation regimes (IR100, IR75, and IR50) with or without the foliar application of FA concentrations. The results showed that the application of 50 mM FA was very effective in improving the plant height, number of secondary branches, number of umbels, and leaf area index in comparison to FA water deficit treated plants alone under IR75 and IR50. Similarly, physiological and gaseous exchange parameters also upgraded that improved the economic yield (81 and 163%), fresh biomass (28 and 131%), dry biomass (63 and 66%), and harvest index (10 and 58%) of C. sativum plants under irrigation regimes IR75 and IR50 compared to their non-treated FA plants. All the observed growth parameters showed a positive correlation with each other vs. LAI except a weight of 1,000. Overall, this study indicated that foliar-applied 50 mM FA may be used as an alternate strategy to improve C. sativum performance in biomass production and can play a key part in solving difficulties caused by drought stress on plant development.

Folic acid is a convenient, affordable growth regulator to increase the efficiency of plants and preserve their nutrients. As far as abiotic stress alleviation is concerned, we have not found sufficient literature explaining the possible role of folic acid in the reduction of water-deficit stress in plants. The role of folic acid in the orchestration of metabolic activities in Coriandrum sativum L. under water deficit conditions has never been documented. This study will open new avenues discussing the role of FA in the enhancement of crop production in drought conditions.

Role of magnesium oxide nanoparticles in the mitigation of lead-induced stress in Daucus carota: modulation in polyamines and antioxidant enzymes.

During the current study, the effects of magnesium oxide nanoparticles (5 mmol/L) were observed on the growth and mineral nutrients of Daucus carota under lead (Pb) stress. The results demonstrated that Pb stress decreased the growth and photosynthetic rate of D. carota plants. Furthermore, Pb stressed plants showed decreased uptake of mineral nutrients including Zn, Na, Fe, K, Ca, Mg, K, and Cu. Similarly, Pb stressed plants showed enhanced electrolyte leakage (EL) and malondialdehyde (MDA) content. However, magnesium oxide nanoparticles detoxified ROS to mitigate Pb stress and improved the growth of plants. Magnesium oxide nanoparticles also escalated the activity of antioxidant enzymes including superoxide dismutase (SOD) and Catalase (CAT). A higher amount of Pb content was observed in the roots as compared to the shoot of plants. Lead toxicity reduced manganese accumulation in D. carota plants. The increased concentration of iron, manganese, copper, and zinc advocates stress the ameliorative role of Pb stress in plants. Novelty statementThe role of MgONPs in the alleviation of Pb-toxicity in Daucus carota has never been exploited. In addition, the potential of MgONPs to enhance nutritional content in D. carota via modulation in antioxidant system and polyamines have never been reported.

Mitigation of lead (Pb) toxicity in rice cultivated with either ground water or wastewater by application of acidified carbon.

Toxicity induced by a high concentration of lead (Pb) can significantly decrease plant's growth, gas exchange, and yield attributes. It can also causes cancer in humans. The use of organic amendments, especially biochar, can alleviate Pb toxicity in different crops. The application of biochar can decrease the uptake of Pb by plant roots. However, the high pH of thermo-pyrolyzed biochar makes it an unfit amendment for high pH soils. As Pb is an acute toxin and its uptake in rice is a major issue, the current experiment was conducted to explore the efficacy of chemically produced acidified carbon (AC) to mitigate Pb toxicity in rice. Lead was introduced in concentrations of 0, 15, and 30 mg kg-1 soil in combination with 0, 0.5, and 1% AC, underground water (GW) and wastewater (WW) in rice plants. The addition of 1% AC significantly improved the plant height (52 and 7%), spike length (66 and 50%), 1000 grains weight (144 and 71%) compared to 0% AC under GW and WW irrigation, respectively at 30 mg Pb kg-1 soil (30 Pb) toxicity. Similar improvements in the photosynthetic rate, transpiration rate and stomatal conductance also validated the effectiveness of 1% AC over 0% AC. A significant decrease in electrolyte leakage and plant Pb concentration by application of 0.5 and 1% AC validates the effectiveness of these treatments for mitigating 30 Pb toxicity in rice compared to 0% AC under GW or WW irrigation. In conclusion, 1% AC is an effective amendment in alleviating Pb toxicity in rice irrigated with GW or WW at 30 Pb.

Enhanced performance of Bacillus megaterium OSR-3 in combination with putrescine ammeliorated hydrocarbon stress in Nicotiana tabacum.

Hydrocarbon stress (HS) has been causing decreased plant growth and productivity. Putrescine (Put) and growth promoting microbes are vital for plant growth and development under hydrocarbon stress. Current research work was carried out to evaluate the potential of Bacillus megaterium OSR-3 alone and in combination with Put to alleviate HS in Nicotiana tabacum (L.). The crude petroleum contaminated soil significantly reduced growth attributes of N. tabacum. B. megaterium OSR-3 inoculated plants subjected to HS exhibited improved photosynthetic rate, gas exchange characteristics, poline contents and protein level. Furthermore, bacterial inoculation enhanced the antioxidative activity of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) in tobacco plants subjected to HS. The HS alleviation in B. megaterium OSR-3 inoculated N. tabacum can be credited to the heightened activity of antioxidative enzymes, reduction in hydrogen peroxide (H2O2) and abridged synthesis of malondialdehyde (MDA). The increased synthesis of indole acetic acid (IAA) in HS stressed N. tabacum plants treated with co-application of B. megaterium OSR-3 and Put attenuated toxicity and amplified growth of plants. Additionally, the co-application of B. megaterium OSR-3 and Put also upregulated the activity of antioxidative enzymes and induced augmented level of proline and IAA in plants under HS regimes. Current research provides novel insight into the potential and mechanism of B. megaterium OSR-3 and Put in mitigation of HS in N. tabacum plants.

Synergistic ameliorative effect of iron oxide nanoparticles and Bacillus subtilis S4 against arsenic toxicity in Cucurbita moschata: polyamines, antioxidants, and physiochemical studies.

The present study was intended to assess the potential of iron oxide nanoparticles (IONPs) and Bacillus subtilis S4 in mitigation of arsenic (As) stress in Cucurbita moschata. Cucurbita moschata seedlings were subjected to As stress for 60 days. Reduced level of growth parameters including photosynthetic pigments, rate of photosynthesis and gas exchange characteristics was observed in seedlings subjected to As stress. However, IONPs and B. subtilis S4 improved growth attributes and proline contents in supplemented C. moschata seedlings. Bacillus subtilis S4 inoculated seedlings showed higher activity of peroxidase (POD) and superoxide dismutase (SOD) under As toxicity. Similarly, the co-application of IONPs and B. subtilis S4 further increased the activity of these antioxidative enzymes. The As stress alleviation in inoculated C. moschata seedlings is credited to reduced levels of hydrogen peroxide (H2O2), malondialdehyde (MDA) and electrolyte leakage (EL) in IONPs and B. subtilis S4-treated plants. Furthermore, synergism between plant growth promoting bacteria (PGPB) and IONPs enhanced the biosynthesis of stress mitigating polyamines including spermidine and putrescine in As-stressed seedlings. Current research reveals that synergistic application of IONPs and B. subtilis S4 is an effective sustainable and ecofriendly approach for alleviation of As stress in C. moschata seedlings.

2-Hydroxymelatonin induced nutritional orchestration in Cucumis sativus under cadmium toxicity: modulation of non-enzymatic antioxidants and gene expression.

2-Hydroxymelatonin (2-OHMT) is an important metabolite produced through melatonin interaction with oxygenated compounds. 2-OHMT pretreated seeds (50 µM, 100 µM, and 150 µM) were grown in soil contaminated with 50 mg kg-1 cadmium. Cadmium imposed stress reduced seed germination, growth, biomass production, and chlorophyll (Chl) content in Cucumis sativus seedlings. 2-OHMT application emphatically revamped germination, shoot length, root length, and plant biomass production. The 2-OHMT pretreatment modulated expression levels of plasma membrane H+-ATPase genes of C. sativus including CsHA2, CsHA3, CsHA4, CsHA8, and CsHA9. This biomolecule amplified the accumulation of antioxidants such as glutathione, proline, phenolics, and flavonoids. The reduced Cd-uptake in 2-OHMT treated C. sativus seedlings encouraged uptake of essential plant nutrients. Furthermore, conjugated increase of indole acetic acid contents and ethylene production rate were observed in 2-OHMT treated seedlings in a dose-dependent manner. The improved nutritional content in 2-OHMT applied seedlings was ascribed to enhanced expression of H+-ATPase regulating genes besides increased amount of non-enzymatic antioxidants in Cd-stressed plants. The present novel study elucidates the potential of 2-OHMT in improving nutritional content in cucumber plants by modulation of non-enzymatic antioxidants and gene expression.

Ameliorative effect of co-application of Bradyrhizobium japonicum EI09 and Se to mitigate chromium stress in Capsicum annum L.

The present study was conducted to explore the potential of Bradyrhizobium japonicum EI09 (EI09) and selenium (Se) alone or in combination to mitigate hexavalent chromium (Cr6+) stress in Capsicum annum L. Chromium stressed plants exhibited significant reduction in biomass, chlorophyll content and gas exchange characteristics. The inoculated seedlings subjected to Cr6+stress showed improvement in growth, proline content, gas exchange attributes and total soluble proteins. Likewise, inoculated C. annum seedlings exhibited augmented activity of ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) under Cr6+ stress. The Cr6+ stress mitigation in inoculated seedlings was ascribed to reduction in malondialdehyde (MDA) content, hydrogen peroxide (H2O2) besides increase activity of flavonoids, proline, phenolic content along with modulation of antioxidative enzymes. The growth-enhancing attributes of bacteria such as indole acetic acid (IAA) content and 1-aminocyclopropane-1-carboxylate deaminase (ACCD) activity enhanced growth in Cr6+-stressed plants. Moreover, co-treatment of EI09 and 5 µM Se effectively mitigated Cr (VI) stress in C. annum plants. Current studies provide a novel insight into potential of B. japonicum EI09 and Se in reduction of Cr6+ toxicity in C. annum plants.