The repertoire of candidate archaeal noncoding RNAs and their association with temperature adaptation

Noncoding RNAs (ncRNAs) play a crucial role in the fine-tuning regulation of cells in all domains of life. In archaea, ncRNAs remain poorly studied, with only a few ncRNA classes well characterised. Archaea are renowned for their ability to survive in harsh environments, though they have been discovered in a variety of other habitats as well. We have determined the ncRNA candidate repertoire across 270 archaeal genomes using secondary structure inferences and sequence similarity searches. Here, 33 non-coding RNA classes were identified in these genomes. The correlation between all ncRNA classes and optimal growth temperature (OGT) was R² 0.65. Phylogenetic analysis based on multiple alignments of a set of highly conserved proteins revealed preferences for ncRNA classes at the phylum and genus levels. All of the ncRNA data generated by this study reveals a correlation between the genomic abundance of specific ncRNA classes and the optimal growth temperature, especially for the sRNA C/D box type. All the genomic and ncRNA archaeal data generated is a valuable resource that will stimulate experimentalists to investigate whether or not their predicted ncRNAs are correct and biologically meaningful, boosting further associative studies using the unique features of this domain.