After silencing suppression: miRNA targets strike back

RNA silencing is both a gene regulatory system and a defense mechanism in plants.Most plant pathogens produce RNA silencing suppressors as part of their infection strategy.The extracellular and intracellular presence of pathogen-derived molecules disrupts the normal functioning of the host RNA silencing.miRNAs regulate multiple genes involved in the RNA silencing machinery, defense, and transcription factor genes.Pathogen-activated silencing suppression results in activation of genes that are under miRNA regulation.miRNAs work as intracellular sensors of pathogen threats that, upon dysfunction, enable a new layer of defense. Within the continuous tug-of-war between plants and microbes, RNA silencing stands out as a key battleground. Pathogens, in their quest to colonize host plants, have evolved a diverse arsenal of silencing suppressors as a common strategy to undermine the host’s RNA silencing-based defenses. When RNA silencing malfunctions in the host, genes that are usually targeted and silenced by microRNAs (miRNAs) become active and can contribute to the reprogramming of host cells, providing an additional defense mechanism. A growing body of evidence suggests that miRNAs may act as intracellular sensors to enable a rapid response to pathogen threats. Herein we review how plant miRNA targets play a crucial role in immune responses against different pathogens. Within the continuous tug-of-war between plants and microbes, RNA silencing stands out as a key battleground. Pathogens, in their quest to colonize host plants, have evolved a diverse arsenal of silencing suppressors as a common strategy to undermine the host’s RNA silencing-based defenses. When RNA silencing malfunctions in the host, genes that are usually targeted and silenced by microRNAs (miRNAs) become active and can contribute to the reprogramming of host cells, providing an additional defense mechanism. A growing body of evidence suggests that miRNAs may act as intracellular sensors to enable a rapid response to pathogen threats. Herein we review how plant miRNA targets play a crucial role in immune responses against different pathogens.