Improved double-stranded RNAs for nanocomposite-driven SIGS in plant virus control

Objective

IMPROVIR is an interdisciplinary project combining nanotechnology, plant molecular biology, and plant virology to control two damaging and emerging plant viruses, Tomato brown rugose fruit virus (ToBRFV) and Cucurbit chlorotic yellows virus (CCVY) via an environment-friendly approach called spray-induced gene silencing (SIGS). Currently, these two viruses are threatening production of tomato, pepper and cucurbits across the globe especially in Europe. SIGS approach is based on RNA-interference (RNAi) technology but it does not involve transgenic manipulation of the plants. The non-transgenic approach of SIGS is an innovative strategy that relies on topical spraying of double stranded RNAs (dsRNAs) on plant surface that enter plant cells and tissues and eventually induce gene silencing by the RNAi mechanism against specific plant pathogens and pests. We will improve the dsRNAs molecules for SIGS by using a tRNAMet tag to enhance dsRNA mobility in the plant. Besides, the enhanced dsRNA molecules will be incorporated into either carbon dot or chitosan-derived nanoparticles in the form of nanocomposites to: (1) increase the stability of the dsRNAs on plant surfaces and (2) increase the delivery of dsRNAs into plants. This approach is fast (compared to time-consuming approaches such as plant breeding, genetic transformation and introduction of resistant varieties), environment-friendly (no residue in products and in environment as opposed to chemical pesticides) and publicly acceptable (no need for genetic transformation and modification). The performance of the dsRNA:NP nanocomposites in controlling those virus diseases will be assessed by evaluating disease progress, virus titers and siRNA production in treated vs. non-treated infected plants. In a non-academic placement at Kimitec, a private biotech company in Spain, the technologies developed at IFAPA (host institution) during the project will be applied to control another important plant pathogen, Phytophthora sp.