Plant Viruses and Marchantia polymorpha: A Novel Defense Mechanism

While plant-virus interactions have been extensively studied in vascular plants, less is known about these relationships in non-vascular species. Ros-Moner and colleagues (Nature Communications) have shed light on this area by investigating the interactions between the non-vascular plant Marchantia polymorpha and viruses.

Plants have developed intricate surveillance systems to detect and eliminate viral infections. These systems often rely on the recognition of viral signatures, either extracellularly (e.g., PAMPs) or intracellularly (e.g., RNA silencing). When double-stranded RNA (dsRNA) from a virus is detected, it is processed into smaller RNA fragments (RiboMarker) called viral small RNAs (vsRNAs). These vsRNAs are then incorporated into proteins from the ARGONAUTE family to target and destroy viral dsRNA precursors.

Ros-Moner et al. employed advanced RNA profiling techniques from RealSeq Biosciences (RealSeq-AC) to analyze the vsRNA response in M. polymorpha. Their results revealed that the majority of vsRNAs were 21 nucleotides long, indicating processing by the DCL4 enzyme, the sole member of the DICER-like family in the M. polymorpha genome.

This study underscores the remarkable ability of plants, even those without vascular systems, to defend themselves against viral threats using RNA silencing mechanisms.