Synthesis, evaluation of activity and toxicity of Nanobiohybrids for seed treatment.

• Grant number: 23/06380-1
• Support Opportunities: Scholarships in Brazil - Master
• Start date: November 01, 2023
• End date: September 30, 2025
• Field of knowledge: Biological Sciences - Biochemistry - Chemistry of Macromolecules
• Principal Investigator: Renata de Lima
• Grantee: Bianca Bertolini Migliorini
• Host Institution: Pró-Reitoria de Pós-Graduação, Pesquisa, Extensão e Inovação. Universidade de Sorocaba (UNISO). Sorocaba , SP, Brazil
• Associated research grant: 21/10639-5 - Center for Research on Biodiversity Dynamics and Climate Change, AP.CEPID

Abstract

Nanotechnology has gained prominence in agriculture due to different application possibilities, such as pest control and fertilization. There are different forms of nanomaterials, with biogenic metallic nanoparticles, which use organisms and metabolites for their synthesis; in this way, it is possible to have synergy between the metabolites and the metal, in addition to presenting versatility, low cost and low toxicity. This proposal intends to synthesize metallic silica, iron and silica/iron bimetallic nanoparticles using bacteria (Bradyrhizobium japonicum and Azospirillum brasilense) and fungus (Trichoderma harzianum), all involved in improving plant growth and maintenance. The proposal also aims to carry out the physical-chemical characterization of nanoparticles, evaluate the activity and effects of exposure on seed germination and plant growth, and evaluate the toxicity in microorganisms of agricultural interest and cell culture. DLS (dynamic light scattering) techniques will be used for size and polydispersion analysis to characterise the synthesised nanoparticle. To measure the zeta potential, electrophoretic mobility will be used, and to obtain size and synthesis concentration, nanoparticle tracking (NTA) will be used. X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) will be used to determine the structure of nanoparticles. The analysis of the microbiota of the seeds before and after exposure to nanoparticles will also be carried out, as well as the evaluation of seed germination. Plate staining tests will evaluate the presence of siderophores, chitinase and cellulase. A disk diffusion test in agar will be used to assess the toxicity of exposure to bacteria of agricultural interest. Cell viability will be measured by mitochondrial activity, Tetrazolium reduction (MTT), Real-Time Cellular Analysis, and genotoxicity by comet assay. The behaviour of the soil microbiota exposed to nanoparticles will be evaluated through molecular analysis. The potential of nanoparticles in controlling the phytopathogens Sclerotinia sclerotiorum, Fusarium oxysporum and Rhizoctonia solani will also be evaluated. At the end of this work, we are expected to have biogenic nanoparticles of silica, iron and silica/iron that present good physicochemical characteristics, high activity, and low toxicity, allowing their safe use in the agricultural area.