Beneficial and Adverse Effects of Gold Nanoparticles on Rhizosphere Biology

Nanoparticles have recently garnered significant interest across various disciplines such as physics, chemistry, material science, medicine, and biology. This heightened attention is a consequence of their distinctive electronic, magnetic, optical, mechanical, and chemical properties. Among the plethora of nanoparticles, gold nanoparticles stand out as particularly valuable, finding extensive applications in both industrial and medical contexts. The rhizosphere is home to a complex and dynamic microbial community, including bacteria, fungi, archaea, and other microorganisms. These microorganisms play crucial roles in nutrient cycling, plant growth promotion, and protection against pathogens. The rhizosphere is a hotspot for interactions between plants and microorganisms. Au-NPs in various studies have shown an increase in microfauna growth when the particle size greater than 45 nm has bacterial growth and also improved germination rate and seedling vigour. Improved rhizosphere led to better plant growth and development. But Au-NPs are proven to be lethal when applied in larger concentration and in smaller sizes (10–15 nm). In order to recommend the use Ai-NPs for crop area there should be clarity regarding beneficial and adverse effects. This chapter will discuss the positive and detrimental aspects of the use of Au-NPs on rhizosphere growth and diversity.