Transient abRNA and steady-state mRNA levels set the thresholds for sense PTGS initiation and amplification

Abstract

Post-transcriptional gene silencing (PTGS) is a conserved RNA-based defense mechanism that protects plants against viruses and other invasive nucleic acids (Tan et al. 2020). During PTGS, double-stranded RNAs (dsRNAs) are processed by DICER LIKE 4 (DCL4) and DCL2 into 21-and 22-nucleotide small interfering RNAs (siRNAs), respectively, which are incorporated into ARGONAUTE (AGO)-containing RNA-induced silencing complexes (RISCs) that recognize and degrade homologous transcripts. In addition to local silencing, PTGS also generates mobile silencing signals that spread systemically throughout the plant (De Meo et al. 2025)