Nanoparticle-driven modulation of DREB/CBF transcription factors enhances lead phytoremediation in diverse plant species

Abstract

Lead (Pb) contamination in the environment poses a significant threat to plant health and ecosystem stability, necessitating advanced strategies to enhance phytoremediation efficacy. In this study, we investigated the potential of foliar-applied nanoparticles (NPs) to modulate stress-responsive transcription factors (DREB1A, DREB1B, DREB1F, and CBF) and biochemical pathways, thereby improving Pb tolerance and accumulation in Cannabis sativa, Ricinus communis, and Parthenium hysterophorus. Plants were subjected to Pb stress (200 ppm) and treated with copper, iron, magnesium, manganese, molybdenum, or zinc NPs (15 ppm), followed by a comprehensive evaluation of genomic responses, biochemical markers, and Pb uptake. Our findings reveal species- and NP-specific regulatory mechanisms governing Pb stress adaptation. Copper and molybdenum NPs markedly up regulated DREB1A and CBF expression in R. communis and C. sativa, correlating with increased proline accumulation (R² = 0.95), phenolic content, and Pb uptake. Molybdenum NPs facilitated the highest Pb accumulation in R. communis (0.63 ± 0.02 mg/g), whereas manganese NPs maximized Pb uptake in C. sativa (0.61 ± 0.05 mg/g). In contrast, P. hysterophorus exhibited minimal DREB1F induction but significant CBF activation under iron NP treatment, leading to Pb accumulation of 0.54 ± 0.05 mg/g. Biochemical analyses demonstrated strong correlations (R² = 0.99) between stress metabolite synthesis and transcriptional regulation, reinforcing the role of NPs in modulating molecular responses to Pb stress. These findings endorse the prime role of nanoparticle-mediated gene activation in enhancing phytoremediation efficiency. By integrating molecular and biochemical insights, this study provides a framework for species-specific NP applications to optimize eco-friendly remediation strategies for heavy metal-contaminated environments.