In this thesis, plant-made nanoparticles derived from Turnip mosaic virus (TuMV), a potyvirus, were developed. These Viral Nanoparticles (VNPs) can be exploited as scaffolds for building modified nano-objects and can be used as diagnostic tools, for antibody generation, immunization, or as biomaterials in general. They fall into two biological categories: either enclosing a nucleic acid (virions) or without the nucleic acid (empty virus-like particles, eVLPs). The modifications imposed on VNPs can also be achieved by two main approaches: genetic or chemical conjugation. Each of them has particular pros and cons for nanotechnological deployment. Overall, this is the first case of genetic or chemical conjugation in plant-made potyvirus VNPs. The VNPs were produced either by inoculation of Indian mustard (Brassica juncea) with the infectious TuMV virus, or by agroinfiltration of the tobacco relative Nicotiana benthamiana with the TuMV coat protein cDNA (CP) on a pEAQ vector for high protein expression. As a proof-of-concept, a human thrombin receptor peptide (TR) for the genetic modification, and a vasoactive intestinal peptide and low-molecular-weight compounds (biotin, organometallics) for the chemical modification, were selected. Significant production of TR-CP VLPs and TuMV virions was obtained from plant leaves. VNPs were observed under an electron microscope after immunodecoration with anti-TR antibody or antibiotin antibody, respectively. Both VNPs proved capacity to log-increase the ability of antibody-sensing compared to free TR peptide or free biotin.In this thesis, the possibility of conjugating, genetically and chemically, peptides and low-molecular-weight compounds to Turnip mosaic virus virions or VLPs is demonstrated. This outlines the potential of these VNPs for their use in numerous nanobiotechnological applications.