Abstract
Plant cells constantly face genetic invasions from both external and internal sources. Viruses and transgenes represent major external threats, while transposable elements (TEs) are endogenous sources of invasive DNA. The early recognition and activation of innate defence mechanisms are therefore critical for maintaining genome integrity. Emerging evidence suggests that foreign genetic elements are detected and processed by the ribosome-associated RNA quality control system, a key cellular pathway responsible for resolving aberrant transcripts with translation defects. One such pathway, known as No-Go RNA Decay (NGD), facilitates RNA cleavage and ribosome dissociation at stalled ribosomes. Genetic and biochemical studies indicate that NGD plays a crucial role in plant antiviral defence and TE regulation, positioning it as a potential first line of defence against invasive genetic elements. This review explores recent advances in plant NGD research, shedding light on the fundamental question of how cells distinguish self from non-self nucleic acids.