biostudies-literatureNavarro BMarie CurieEuropean Union’s Horizon 2020 research and innovation program2265https://www.ebi.ac.uk/biostudies/studies/S-EPMC9608096biostudies-literatureUnknown14(10)Viroid and viroid-like satellite RNAs are infectious, circular, non-protein coding RNAs reported in plants only so far. Some viroids (family <i>Avsunviroidae</i>) and viroid-like satellite RNAs share self-cleaving activity mediated by hammerhead ribozymes (HHRzs) endowed in both RNA polarity strands. Using a homology-independent method based on the search for conserved structural motifs of HHRzs in reads and contigs from high-throughput sequenced RNAseq libraries, we identified a novel small (550 nt) viroid-like RNA in a library from a <i>Citrus reticulata</i> tree. Such a viroid-like RNA contains a HHRz in both polarity strands. Northern blot hybridization assays showed that circular forms of both polarity strands of this RNA (tentatively named citrus transiently-associated hammerhead virVirusesA Novel Self-Cleaving Viroid-Like RNA Identified in RNA Preparations from a Citrus Tree Is Not Directly Associated with the Plant.PMC9608096734736No. 734736 (project 'VirFree').Gisel ALi SChiumenti MMinutolo MAlioto DNavarro BDi Serio FfalseA Novel Self-Cleaving Viroid-Like RNA Identified in RNA Preparations from a Citrus Tree Is Not Directly Associated with the Plant.Viroid and viroid-like satellite RNAs are infectious, circular, non-protein coding RNAs reported in plants only so far. Some viroids (family <i>Avsunviroidae</i>) and viroid-like satellite RNAs share self-cleaving activity mediated by hammerhead ribozymes (HHRzs) endowed in both RNA polarity strands. Using a homology-independent method based on the search for conserved structural motifs of HHRzs in reads and contigs from high-throughput sequenced RNAseq libraries, we identified a novel small (550 nt) viroid-like RNA in a library from a <i>Citrus reticulata</i> tree. Such a viroid-like RNA contains a HHRz in both polarity strands. Northern blot hybridization assays showed that circular forms of both polarity strands of this RNA (tentatively named citrus transiently-associated hammerhead vir2022-01-01T00:00:00Z2022 Oct2026-04-08T11:59:40.526Z2025-04-19T11:45:40.391ZS-EPMC96080963629882010.3390/v14102265