Abstract
Modern plant breeding is still a time-consuming and costly process, even with the most advanced technologies such as gene editing. Hence, there is an urgent need to develop alternative means for plant trait manipulation and plant protection. RNA interference (RNAi) is a conserved cellular mechanism mediated by naturally occurring double-stranded RNA (dsRNA) and small RNAs (sRNAs) that can target mRNAs for destruction or transcript reduction. Here, we review the potential of technology based on RNAi, called spray-induced gene silencing (SIGS), as an alternative or adjunct to breeding for manipulation of endogenous gene expression in plants or pathogen control. SIGS based on exogenous application of RNA molecules in plants may be especially useful in reducing pest or pathogen impacts, thereby ameliorating biotic stresses and increasing the agronomic performance of crops.
Highlights
Over the last century, global food demand has increased due to the quadrupling of the human population from 1.8 billion people in 1915 to 7.9 billion at present and is expected to rech 9.7 billion by 2050 (UN 2019)
These reports demonstrate that accumulation of specific mRNAs can be targeted by exogenously applied double-stranded RNA (dsRNA) in both above and below ground plant parts, but that the uptake of the dsRNA can be strongly influenced by the formulation
Further research is necessary to establish whether high-pressure spraying is functional in targeting plant endogenous genes, or if dsRNA uptake from spray application can be improved through addition of adjuvants to the dsRNA formulation
Summary
Global food demand has increased due to the quadrupling of the human population from 1.8 billion people in 1915 to 7.9 billion at present and is expected to rech 9.7 billion by 2050 (UN 2019). Global food production demands can only be met by integrating modern breeding and plant biotechnological tools for precision farming to maximize edible yields and minimize losses to both biotic and abiotic stresses. Not all crop plants are amenable to genetic modification with tools such as gene editing, or they have breeding cycles that require years between crosses and subsequent phenotyping (e.g. trees). Crop Breeding and Applied Biotechnology - 21(S): e387921S11, 2021 new sustainable and GMO-free approaches to improve plant traits and agronomic performance, that support and work in parallel with modern breeding. Research elsewhere has shown that gene silencing approaches can aid precision breeding and plant protection via manipulation of plant traits involved in growth and different stress tolerances (biotic and abiotic) (Younis et al 2014). RNAi approaches involving topical application of RNA molecules directly on plants (SIGS) are discussed (Figure 1)
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