Beyond “spray and pray” – Understanding mechanisms of exogenous RNA uptake and stability in plants

Beyond "spray and pray" -Understanding mechanisms of exogenous RNA uptake and stability in plants Exogenous RNA applications are gaining momentum as innovative tools in crop protection and research 1,2,3 .Using the mechanism of RNA interference (RNAi), they allow highly specific silencing of mRNA targets, not only in plants but also in a wide range of pests and pathogens.For an effective RNAi response, efficient uptake of exogenous RNAs into plant leaves is essential.Here, several biological barriers must be overcome to transport RNA molecules from the leaf surface into the mesophyll and ultimately into target cells.In addition, exogenous RNAs require protection from premature degradation to maintain their efficacy.While RNA-based approaches are advancing rapidly, their successful implementation in different plant species remains a challenge 4 .Establishing a functional and efficient exogenous RNA delivery system is often a time-consuming process, complicated by species-specific anatomical and biochemical factors.As a result, optimisation still follows a trial-and-error approach, often described as "spray and pray".To overcome this issue, we aim to:The concept of key factors