MicroRNA regulatory networks in horticultural grasses: from cereal models to architecture, resilience, and translational strategies

Abstract

Bamboo, turfgrasses, and other perennial ornamental or landscape grasses extend the significance of Poaceae beyond cereal production. However, direct functional evidence for microRNA (miRNA) action in these plants remains limited. This review draws on rice, maize, and wheat as reference species to assess what current evidence can and cannot establish regarding miRNA regulation in horticulturally important grasses. We argue that grass miRNAs are better understood as dosage-sensitive network regulators than as simple on-off switches. Conserved miRNA–target modules recurrently shape phase change, organ polarity, architecture, regeneration, and stress-associated growth responses. We then examine how nutrient stress, redox control, host–invader interactions, polyploidy, lineage-specific miRNAs, and domestication alter regulatory output across grass lineages. Throughout, we distinguish direct functional evidence from transcriptomic association and cross-species inference because the transferability of cereal-based evidence to other perennial grasses remains uneven. Finally, we assess deployment strategies, including target-site tuning, miRNA-locus editing, target mimicry, artificial miRNAs, and external RNA delivery, and argue that phenotypic gains are most likely when interventions focus on well-validated nodes and are evaluated across genotypes and environments. This framework positions miRNAs as quantitative regulators of horticulturally relevant grass traits and clarifies whether the present evidence base is strong enough to support deployment.