Elucidating Cu-based nanoparticles' fate on and in grapevines' leaves for the rational design of more efficient Cu-fungicides.

Copper salts are sprayed on grapevine leaves to treat fungal diseases, especially in organic agriculture where it is the only allowed fungicides. Yet, they are rapidly washed off to vineyard soils leading to severe agroecosystems contaminations. Cu-based nanoparticles can be an efficient alternative, as they present drastically reducing copper wash-off and subsequent soil contamination. Further, organic polymer coating like chitosan is efficient at controlling labile nanoparticle dissolution. Yet, the foliar uptake and the spatially resolved transformation of these nanoformulations at the leaf interface remain unknown, preventing the understanding of their mode of action and their rational design. In this proposal, we propose to analyse treated grapevine leaves with bare and functionalized CuONPs, to unravel the foliar translocation routes of copper, along with the associated transformation of the various species.