Salt stress presents a major obstacle to maize (Zea mays L.) production globally, impeding its growth and development. In this study, we aimed to identify salt-tolerant maize varieties through evaluation using multivariate analysis and shed light on the role of ionome, antioxidant capacity, and autophagy in salt tolerance. We investigated multiple growth indices, including shoot fresh weight, shoot dry weight, plant height, chlorophyll content, electrolyte leakage, potassium and sodium contents, and potassium-to-sodium ratio in 20 maize varieties at the V3 stage under salt stress (200 mM NaCl). The results showed significant differences in the growth indices, accompanied by a wide range in their coefficient of variation, suggesting their suitability for screening salt tolerance. Based on D values, clustering analysis categorized the 20 varieties into four distinct groups. TG88, KN20, and LR888 (group I) emerged as the most salt-tolerant varieties, while YD9, XD903, and LH151 (group IV) were identified as the most sensitive. TG88 showcased nutrient preservation and redistribution under salt stress, surpassing YD9. It maintained nitrogen and iron levels in roots while YD9 experienced decreases. TG88 redistributed more nitrogen, zinc, and potassium to its leaves, outperforming YD9. TG88 preserved sulfur levels in both roots and leaves, unlike YD9. Additionally, TG88 demonstrated higher enzymatic antioxidant capacity (SOD, POD, APX, and GR) both at the enzyme and gene expression levels, upregulation of autophagy-related (ATG) genes (ZmATG6, ZmATG8a, and ZmATG10), and increased autophagic activity. Overall, this study offers insights into accurate maize varieties evaluation methods and the physiological mechanisms underlying salt tolerance and identifies promising materials for further research.

Green syntheses of nanoparticles using plant materials are of tremendous scope. Here we report advantageous green synthesis for silver nanoparticles (AgNPs) using aqueous-root extract of Jurinea dolomiaea and AgNO₃. Color change of solution and UV-Vis absorption at 444 nm indicated the formation of AgNPs. XRD confirmed their face centered cubic structure (fcc) with average particle size of 24.58 nm. SEM analysis showed their spherical, cubic and triangular structures. FT-IR indicated the presence of functional groups of reducing and stabilizing phytochemicals. Methanol-root extract of J. dolomiaea revealed high flavonoid (445 mg RE/g) and phenolic contents (92 mg GAE/g). Methanol-extract showed high antioxidant potency (IC₅₀ = 0.494 μg/mL), rationally due to its high phenolic and flavonoid contents. These AgNPs showed the highest and equal antimicrobial activities against Escherichia coli and Pseudomonas aeruginosa (Inhibition zone 11.0 mm) whereas, methanol-roots extract showed equal and intermediate activities (Inhibition zone 8.0 mm) against both pathogens but aqueous extract showed poor activities (Inhibition zone 6.0 mm) against these both pathogens. AgNPs are playing a major role in the field of nanotechnology and nanomedicine due to their antimicrobial and drug delivery efficacy as well as reasonable tolerance in human biology.

Nickel oxide nanoparticles (NiO-NPs) pose potential threats to agricultural production. Bacillus subtilis has emerged as a stress-mitigating microbe that alleviates the phytotoxicity caused by NiO-NPs. However, the mechanisms underlying its effectiveness, particularly in root-nodule symbiosis and biological N₂-fixation (BNF), remain unclear. Here, we tested the combined exposure of NiO-NPs (50 mg kg⁻¹) and B. subtilis on soybean (Glycine max L.) growth and BNF. Combined exposure increased root length, shoot length, root biomass, and shoot biomass by 19-26%, while Ni (200 mg kg⁻¹) reduced them by 38--53% compared to the control. NiO-NPs at 100 and 200 mg kg⁻¹ significantly (P < 0.05) reduced nodule formation by 16% and 58% and Nitrogen assimilation enzyme activities levels (UE, NR, HS, and GOGAT) by 13-57%. However, co-exposure with B. subtilis improved nodule formation by 22-44%. Co-exposure of NiO-NPs (200 mg kg⁻¹) with B. subtilis increased POD, CAT, and GSH-Px activity levels by 20%, 16%, and 14% while reducing MDA (14%) and H₂O₂ (12%) levels compared to NiO-NPs alone. Additionally, co-exposure of NiO-NPs (100 and 200 mg kg⁻¹) with B. subtilis enhanced the relative abundance of Stenotrophomonas, Gemmatimonas, and B. subtilis, is associated with N2-cycling and N2-fixation potential. This study confirms that B. subtilis effectively mitigates NiO-NP toxicity in soybean, offering a sustainable method to enhance BNF and crop growth and contribute to addressing global food insecurity.