Small Regulatory RNAs in Prokaryotes: Key Features, Identification, Environmental Roles, and Applications.

Small non-coding RNAs (sRNAs) are ubiquitous post-transcriptional regulators that enable rapid bacterial adaptation to fluctuating environments. Previous reviews have largely focused on sRNA mechanisms in model organisms. This review integrates computational prediction, meta-omics-based discovery, and synthetic biology applications of small regulatory RNAs in marine and environmental prokaryotes, providing a multi-layered perspective from identification to functional and engineering applications. The current landscape of sRNA identification tools is critically evaluated, with emphasis on strategies to overcome challenges such as false-positive predictions. Recent advances in mapping the RNA interactome and emerging evidence of previously underappreciated roles of sRNAs in environmental adaptation are discussed. Additionally, metagenomic and metatranscriptomic studies revealing the diversity of environmental sRNAs in uncultured microbial communities are summarized, highlighting their ecological significance. Finally, a curated overview of synthetic sRNA applications in metabolic engineering, including target genes and enhanced product yields, is provided as a resource for strain engineering. Collectively, this review provides a holistic view of prokaryotic sRNA biology, distinguishing it from more narrowly focused studies. Overall, sRNAs are highlighted as key regulatory elements linking microbial environmental adaptation with emerging biotechnological applications through advances in meta-omics guided discovery and synthetic RNA engineering.