Designer antisense circRNAGFPreduces GFP protein abundance in transgenic Arabidopsis protoplasts in a sequence-specific manner, independent of RNAi pathways

Abstract

AbstractCircular RNAs (circRNAs) are single-stranded molecules that have attracted increasing attention in recent years due to their covalently closed structure and their diverse functional roles in mammalian cells, where they are involved in the regulation of gene expression and protein function. Increasing evidence suggests that circRNAs have similar functions in plants, where they play a role in plant development, resistance to biotic stress, and abiotic stress tolerance. Here, we investigated the agronomically relevant question of whether synthetic designer circRNAs can be used to modulate in a sequence-specific manner gene expression in plants. We show that treatment ofGFP-expressing Arabidopsis protoplasts with designer 50 nt GFP antisense circRNA (circRNAGFP) reduces the cellular accumulation of the reporter protein in a sequence-specific and dose-dependent manner. This inhibitory activity of circRNAGFPwas not abolished in various Arabidopsisagoanddclmutants with defective RNAi pathways. Moreover, and in contrast to other types of RNA such as double-stranded (ds)RNA, circRNAs did not induce a PTI response in plant leaves. We discuss the possibility that circRNA may be applied to regulate endogenous plant genes and thus may have future potential as a novel bioherbicide.