Post-Transcriptional Gene Silencing Conferred by the Ectopic Expression of the Grapevine miRNA-g1 and Inhibition of the Response by Anti-miRNA-g1 Inhibitor

Our results show that a subset (miRNA cluster 1) of grapevine (Vitis vinifera L., cv. Limberger) microRNAs (miRNAs) can be strongly induced by different apoptosis inducers including methyl jasmonate (MeJA), botrycin, cinerein and/or H 2 O 2 . We report here that the expression of endogenous miRNA-g1 and miRNA-g7 can be efficiently silenced in grapevine protoplasts using artificial miRNA (amiRNA) technology. Furthermore, we demonstrate that the ectopic expression of amiRNAs (anti-mir miRNA-g1 and pre-mir miRNA-g1) designed to target a mature miRNA-g1 directs jasmonate-induced silencing against DAD1 protein (defender against death 1). These collective results strongly support the idea that a sub-population of grapevine miRNAs induced by apoptosis may function in one of the most critical defense systems for structural and mechanical fitness.