microRNAs and stress adaptation in grasses: A systematic review

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression after transcription, playing crucial roles in plant development and stress adaptation. In grasses, this regulation is vital under isolated biotic and abiotic stress conditions and combined stress scenarios, although many regulatory modules remain unexplored. This systematic review examined 60 studies out of 1823 publications indexed in Scopus, focusing on grass miRNAs with validated targets through Degradome-Seq and/or RACE approaches. Results indicate that miRNA-target modules were validated more often under abiotic stress than biotic or combined stress conditions. The most frequently studied miRNA families include miR156, miR159, miR164, miR169, and miR396, which are commonly linked to various types of stress, whether isolated or combined. Most research has concentrated on major crops such as rice and maize, with limited studies on other agriculturally important grasses. This review highlights advances in miRNA-phytohormone interactions, systemic signaling, and target validation strategies. It also underscores the potential of biotechnological tools such as RNAi, artificial miRNAs, target mimicry, and CRISPR/Cas for engineering more resilient grasses. Integrating multi-omics approaches and an increasing focus on combined stress responses suggest promising strategies for sustainable agriculture, food security, and bioenergy production amidst climate challenges. Together, these advances strengthen the potential of microRNA-based regulation as a key tool for enhancing crop resilience and adaptation.