Isolation of retron-bearing hosts from environmental samples. Top: Schematic of the isolation of bacteria from soil and water samples and identification of possible retron-bearing hosts using PAGE analysis (from left). Retron RT-DNA bands from PAGE analyses. Overview of sampling, screening of colonies, and identification of retron hosts. Hosts displaying an RT-DNA band were subjected to whole-genome sequencing. RT-DNA was subjected to unbiased adapter addition and sequencing. Bottom: Top left panel: Schematic of canonical retron operon with components annotated, effector in pink, noncoding RNA (ncRNA) in orange, and reverse transcriptase in purple. Other seven panels: Seven putative retron operons, identifying the retron type, host species, and predicted two-dimensional structure of the ncRNA. For retrons where RT-DNA sequencing is available, sequencing coverage is plotted onto ncRNA in an orange heatmap (heatmap legend indicated number of sequencing reads mapped). Gene abbreviations: NDT (nucleoside deoxyribosyltransferase-like); PRTase (phosphoribosyltransferase); WH (winged helix-turn-helix DNA binding); HTH (helix-turn-helix domain containing); HipA (HipA-like); DUF (DUF3037 domain-containing protein).
Bacteria rely on retrons for #phage defense, but most known systems come from clinical or lab strains. @seth-shipman.bsky.social &co identify diverse #retrons from environmental #bacteria, uncovering their defense mechanisms & using them as #GenomeEditing tools @plosbiology.org 🧪 plos.io/4oDqRAF
