In this study, initially 11 different bacterial strains were tested for the degradation capabilities against Basic Orange 2 dye. In initial screening with 78.90% degradation activity, Escherichia coli emerged as the most promising strain to degrade the selected dye, and was then employed in subsequent experiments. For further enhancing the degradation capability of selected bacteria, the effects of various physicochemical parameters were also evaluated. Among the tested parameters, 20 ppm dye concentration, 1666 mg/L glucose concentration, a temperature of 40 °C, 666 mg/L sodium chloride concentration, pH 7, 1000 mg/L urea concentration, a 3-day incubation period and the use of sodium benzoate as a redox mediator (666 mg/L) were found to be ideal conditions to get the highest decolorization/degradation activities. Finally, all the mentioned parameters were combined in a single set of experiments, and the decolorization capacity of the bacteria was enhanced to 89.88%. The effect of pH, dye concentration, incubation time and temperature were found to be responsible for the optimum degradation of dye (p < 0.05), as predicted from the ANOVA (analysis of variance) of the response surface methodology. The metabolites were collected after completion of the process and characterized through Fourier transform irradiation (FTIR) and gas chromatography mass spectrometry (GC-MS). From the data obtained, a proposed mechanism was deduced where it was assumed that the azo bond of the dye was broken by the azoreductase enzyme of the bacteria, resulting in the formation of aniline and 3, 4-diaminobezeminium chloride. The aniline was then further converted to benzene by deamination by the action of the bacterial deaminase enzyme. The benzene ring, after subsequent methylation, was transformed into o-xylene, while 3, 4-diaminobezeminium chloride was converted to p-xylene by enzymatic action. These findings suggest that Escherichia coli is a capable strain to be used in the bioremediation of textile effluents containing azo dyes. However, the selected bacterial strain may need to be further investigated for other dyes as well.

Genetic diversity and Agro-climatic conditions contribute significantly to the agronomic and morphological features of the food plant species, and their nutraceutical potential. The present study was intended to evaluate the impact of growing conditions on total phenolic and total flavonoid contents, and in vitro antioxidant potential in the bulbs and leaves of onion varieties planted under diverse environmental conditions. Standard analytical methods were used to quantify total phenolic content (TPC), total flavonoid content (TFC), and free radicals’ scavenging/antioxidant capacity. The impact of climatic and soil conditions was assessed using statistical tools. In general, onion varieties cultivated at three different locations viz. Kalar Kahar, Lahore and Swabi exhibited significant variations in TPC and TFC, and antioxidant activities. The bulbs and leaves of Mustang (V1) variety planted at Lahore and Swabi had significantly (p < 0.05), high levels of TPC (659.5 ± 6.59, and 631.1 ± 8.58 mg GAE/100 g, respectively). However, leaves of Red Orb (V2) and bulbs of Mustang (V1), and Golden Orb (V6), harvested from Kalar Kahar depicted the highest concentration of TFC (432.5 ± 10.3, 303.0 ± 6.67, and 303.0 ± 2.52 mg QE/100 g DW, respectively). Likewise, bulbs of V1 planted at Kalar Kahar, Lahore and Swabi exhibited maximum inhibition of DPPH, ABTS, and H₂O₂ radicals (79.01 ± 1.49, 65.38 ± 0.99, and 59.76 ± 0.90%, respectively). Golden Orb (V6) harvested from Lahore had the highest scavenging of OH radical (67.40 ± 0.09%). Likewise, bulbs of V1 variety planted at KalarKahar and Swabi had significant capacity to scavenge ferric ions (415.1 ± 10.6 mg GAE/100 g DW), and molybdate ions (213.7 ± 0.00 mg AAE/100 g DW). Conversely, leaves of Amazon (V8), planted at Lahore and Swabi depicted significant levels of DPPH, ABTS, H₂O₂ radical scavenging (90.69 ± 0.26, 63.55 ± 1.06, 51.86 ± 0.43%, respectively), and reduction of ferric ions (184.2 ± 6.75 mg GAE/100 g DW). V6 leaves harvested from Lahore and that of Super Sarhad (V3) from Swabi showed the highest inhibition of OH radical (61.21 ± 0.79%), and molybdate ions (623.6 ± 0.12 mg AAE/100 g DW), respectively. Pearson correlation and principal component analysis revealed strong relationships of climatic conditions, soil properties and elevation with TPC, TFC and free radicals’ scavenging potential in the bulbs and leaves of onion varieties. The variations in the total phenolic and flavonoid contents, and antioxidant potential of different varieties, and their associations with climatic and soil factors revealed the complexity of the growing conditions and genetic makeup that imposed significant impacts on the synthesis of secondary metabolites and nutraceutical potential of food and medicinal plant species.

Biofilm forming ability of Pseudomonas aeruginosa make them vulnerable, because it makes them recalcitrant against various antibiotics. Quorum sensing (QS) is cell density based signaling that helps in bacterial cell-cell communication, which regulated various virulence factors such as pigment and biofilm formation that contribute in the establishment of chronic infections. The interruption of QS is one of the effective approach to control various virulence factors. Present study was intended with the aim to authenticate antibiofilm potential in different solvents based extracts of selected medicinal plant species viz. Berginia ciliata, Clematis grata and Clematis viticella traditionally used by the inhabitants of Himalayan region of Pakistan to treat various pathogenic diseases. P. aeruginosa PAO1, an opportunistic pathogen and involves in various life-threatening infections specifically in immune deficient patients was used as a model pathogen. Plants were extracted in various organic (ethanol, methanol, acetone, ethyl acetate, hexane, chloroform) as well as in aqueous solvents and their ability to inhibit biofilm was measured. Biofilm of PAO1 was grown in Jensen's medium while growing at 30°C and crystal violet assay was performed to assess the biofilm inhibiting activity of plant extracts. Solvents play a vital role in extraction of plant components and it was found that the plants in various solvents exhibit different activity against the PAO1 biofilm. Comparatively, 1% methanolic extract of B. ciliata (rhizome with skin), showed more than 80% inhibition of biofilm formation without effecting on the growth of the bacterium. Significant correlation between flavonoids content and antibiofilm activity in methanolic extract revealed the contribution of secondary metabolites in P. aeruginosa (PAO1) biofilm inhibition. Our study revealed that plants under investigation more specifically B. ciliata could be a potential candidate for drug discovery to treat P. aeruginosa PAO1, induced infectious diseases especially for its biofilm treatment.

Nitrogen fertilization and irrigation patterns have been extensively studied for common maize (Zea mays L.), but there is limited published work for Zhengda 619, especially in subtropical areas. Nitrogen (N) fertilizer and irrigation play an important role in crop growth and yield improvements. The study aimed to investigate the yield, growth, chlorophyll content, reactive oxygen species (ROS) and enzyme activities of hybrid maize (Zhengda 619) under greenhouse conditions. Individual plants grown in plastic pots were subjected to two irrigation types—low irrigation (LW; 60% field capacity) and high irrigation water (HW; 80% field capacity)—and five N rates. Our results demonstrate that the LW irrigation increased dry matter, kernel yield, leaf chlorophyll, total root length, root diameter, root volume, and root surface area, as well as soil enzymes and plant antioxidant enzymes, while it lowered malondialdehyde (MDA), proline, and ROS. Moreover, most of the above parameters increased with increasing N application rates up to N3 under LW irrigation due to the increased N availability to the plant and soil enzymes. It is concluded that increasing N rates could improve soil enzyme activities as well as plant antioxidant enzymes and decrease ROS, ultimately resulting in a higher kernel yield under LW irrigation.

Maize (Zea mays L.) is a salt-sensitive plant that experiences stunted growth and development during early seedling stages under salt stress. Salicylic acid (SA) is a major growth hormone that has been observed to induce resistance in plants against different abiotic stresses. Furthermore, plant growth-promoting rhizobacteria (PGPR) have shown considerable potential in conferring salinity tolerance to crops via facilitating growth promotion, yield improvement, and regulation of various physiological processes. In this regard, combined application of PGPR and SA can have wide applicability in supporting plant growth under salt stress. We investigated the impact of salinity on the growth and yield attributes of maize and explored the combined role of PGPR and SA in mitigating the effect of salt stress. Three different levels of salinity were developed (original, 4 and 8 dS m⁻¹) in pots using NaCl. Maize seeds were inoculated with salt-tolerant Pseudomonas aeruginosa strain, whereas foliar application of SA was given at the three-leaf stage. We observed that salinity stress adversely affected maize growth, yield, and physiological attributes compared to the control. However, both individual and combined applications of PGPR and SA alleviated the negative effects of salinity and improved all the measured plant attributes. The response of PGPR + SA was significant in enhancing the shoot and root dry weights (41 and 56%), relative water contents (32%), chlorophyll a and b contents (25 and 27%), and grain yield (41%) of maize under higher salinity level (i.e., 8 dS m⁻¹) as compared to untreated unstressed control. Moreover, significant alterations in ascorbate peroxidase (53%), catalase (47%), superoxide dismutase (21%), MDA contents (40%), Na⁺ (25%), and K⁺ (30%) concentration of leaves were pragmatic under combined application of PGPR and SA. We concluded that integration of PGPR and SA can efficiently induce salinity tolerance and improve plant growth under stressed conditions.

Cupressus macrocarpa Hartw and Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson, widely grown in many subtropical areas, are used for commercial purposes, such as in perfumery, cosmetics, and room fresheners. Their potential as a source of antimicrobial compounds may be useful in different applications. The chemical composition of essential oils (EOs) from C. macrocarpa branchlets and C. citriodora leaves was analyzed by using gas chromatography–mass spectrometry (GC/MS). Antibacterial and antifungal activities were assessed by the micro-dilution method to determine the minimum inhibitory concentrations (MICs), and minimum fungicidal concentrations (MFCs), and minimum bactericidal concentrations (MBCs). Further, the antioxidant capacity of the EOs was determined via 2,2′-diphenypicrylhydrazyl (DPPH) and β-carotene-linoleic acid assays. Terpinen-4-ol (23.7%), α-phellandrene (19.2%), α-citronellol (17.3%), and citronellal were the major constituents of EO from C. macrocarpa branchlets, and α-citronellal (56%), α-citronellol (14.7%), citronellol acetate (12.3%), isopulegol, and eucalyptol were the primary constituents of EO from C. citriodora leaves. Antibacterial activity with MIC values of EO from C. citriodora leaves was ranged from 0.06 mg/mL to 0.20 mg/mL, and MBC from 0.12 mg/mL against E. coli to 0.41 mg/mL. EO from C. macrocarpa branchlets showed less activity against bacterial strains. The MIC values against tested fungi of the EO from C. citriodora ranged from 0.11 to 0.52 mg/mL while for EO from C. macrocarpa from 0.29 to 3.21 mg/mL. The MIC and MFC values of EOs against P. funiculosum were lower than those obtained from Ketoconazole (KTZ) (0.20; 0.45; 0.29 and 0.53 mg/mL, respectively, vs 0.21 and 0.41 mg/mL. Antioxidant activity of the EO from C. citriodora was higher than that of the positive control but lower than that of the standard butylhydroxytoluene (BHT) (IC50 = 5.1 ± 0.1 μg/mL). The results indicate that the EO from Egyptian trees such as C. citriodora leaves may possesses strong bactericidal and fungicidal activities and can be used as an agrochemical for controlling plant pathogens and in human disease management which will add crop additive value.