Actinobacteria mediated synthesis of silver nanoparticles and their weedicidal potential against Parthenium hysterophorous Linnaeus.

Parthenium hysterophorus, identified as Congress weed, presents a considerable risk to agricultural ecosystems and human health owing to its invasive characteristics and allelopathic properties. In this study, we explore the potential of biosynthesized silver nanoparticles (AgNPs) using actinobacteria as a sustainable and effective product for inhibiting the growth of P. hysterophorus. Actinobacteria, known for their diverse metabolic capabilities, were isolated and utilized for the eco-friendly synthesis of AgNPs. The reaction mixture consisted of an aqueous silver nitrate solution (1 mM) and the cell-free culture supernatant of Actinobacteria, which served as a source of reducing and stabilizing metabolites for the biosynthesis of silver nanoparticles. The resultant AgNPs were characterised employing several analytical techniques, such as UV-Vis spectroscopy and transmission electron microscopy. The synthesized AgNPs exhibited distinct physicochemical properties such as a surface plasmon resonance peak at ~ 420 nm, spherical shape, nanoscale size of 20.2 nm, confirming their successful formation. Subsequently, the inhibitory activity of actinobacteria-synthesized AgNPs against P. hysterophorus was evaluated through comprehensive bioassays. The nanoparticles demonstrated remarkable inhibition of seed germination, seedling growth, and overall plant development. Moreover, the AgNPs displayed selective toxicity towards Parthenium weed while maintaining minimal impact on non-target plants, emphasizing their potential as a targeted and environmentally friendly solution. The study highlights the promising role of actinobacteria-synthesized AgNPs in managing P. hysterophorus, providing valuable insights into the development of sustainable strategies for weed control. This research contributes to the growing field of nanobiotechnology, showcasing the potential of bioengineered nanoparticles as an effective means to address invasive plant species and promote sustainable agricultural practices.