NANOBIOAGRI - Plant disease biocontrol by means of non-infectious biodegradable proteinaceous nanoparticles
Elodie Vandelle, Università degli Studi di Verona; Italy
plant protection, biocontrol, virus-like nanoparticles, antimicrobial peptides, plant defence elicitors
Pesticides are widely used in agricultural production to reduce crop yield losses and maintain high product quality. However, although pesticides are developed through very strict regulation processes, serious concerns have been raised about health risks and their impacts on environment. Thus there is a current need for alternative crop protection systems with improved safety profiles. The present proposal aims to develop a new form of biocontrol of plant pathogens, through the deployment of fully biodegradable biomolecules. These will be based on targeted peptides with eliciting or antimicrobial activities and viral nanoparticles (VNPs), completely proteinaceous in nature, derived from Turnip mosaic virus (TuMV) or Cowpea mosaic virus (CPMV). Indeed, antimicrobial peptides (AMPs) have emerged as key components of the innate immune system in almost all living organisms and have gained a great interest to help plant species fight microbial diseases. However, the majority of AMPs showing potential for plant disease immunity are often tested using in vitro assays. Thus, the greatest challenge remains the functional validation of candidate AMPs in plants and the demonstration of the feasibility of their use for plant protection in the field. On the other hand, the elicitation of plant innate immune system, which relies on the detection of microbe-derived peptides, or immunity-triggering peptides (ITPs), triggers a common, stereotype set of defence responses, which protects plants against further infection with a broad range of pathogens. However, though efficient, AMPs and ITPs directly applied to plants are poorly stable mainly due to proteolytic digestion. In addition the use of AMPs and ITPs is limited by their low bioavailability and the still prohibitive cost of their synthesis. Together this highlights the need to combine AMPs/ITPs with new delivery techniques for developing sustainable agriculture. According to reports from both the USA and Europe these techniques may well be based on nanotechnology. In this context, virus nanoparticles (VNPs), proteinaceous structures with a normal virus architecture but without any genetic material, deserve great attention, as they can be specifically modified to display peptides of interest on their surface. In this project, VNPs will be functionalized with synthetic and “green” AMPs, i.e. of a plant origin, such as thionins defensins, as well as with ITPs, derived from bacterial flagellin and harpin, to confer them phytosanitary properties against a whole range of plant pathogens. Another great advantage of this innovative technology is that functionalized VNPs will be produced on large scale using plants as “bioreactors”, thus allowing an eco-friendly, cost-effective production. Both purified VNP-AMPs/ITPs and crude extracts containing these particles will be applied to and validated on different pathosystems, including fungi, oomycetes and bacteria responsible for diseases in grapevine, apple, pear, calla lily or potato.