Nucleic Acids Research, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 27, 2024

Abstract Viroids, the agents of several plant diseases, are smallest and simplest known replicators that consist covalently closed circular (ccc) RNA molecules between 200 400 nucleotides in size. Viroids encode no proteins rely on host polymerases for replication, but some contain ribozymes involved replication intermediate processing. Although other viroid-like with cccRNAs genomes, such as satellite RNAs, ribozyviruses retrozymes, have been discovered, until recently, spread these biosphere appeared narrow, their actual diversity evolution remained poorly understood. Extensive, targeted metatranscriptome mining dramatically expanded genomes. These searches identified numerous, diverse cccRNAs, many found environments devoid animal material, suggesting unicellular eukaryotic and/or prokaryotic hosts. Several by CRISPR systems, supporting association bacteria. In addition to small viroid size range, a broad variety novel viruses genomes reaching nearly 5 kilobases, were discovered. Thus, shows is far greater than previously suspected, prompting reassessment relevance understanding primordial world.

Language: Английский