The role of miRNA in regulating seed vigor

Seed vigor is a seed-lot property that describes the potential for rapid, uniform emergence and normal seedling establishment across various environmental conditions. It also includes the ability to maintain this performance during storage. It is distinct from physiological traits such as vitality, final germination rate, and dormancy release. MicroRNAs (miRNAs) are a class of endogenous non-coding RNAs, with a length of approximately 18 to 24 nucleotides. As key post-transcriptional regulators, they guide the cleavage of target mRNAs or inhibit their translation. In this way, they play a pivotal role in the growth and development, metabolism, and stress responses of plants. This review summarizes the recent advancements in the regulatory roles of miRNAs in various aspects, such as the establishment and maintenance of seed vigor, the accumulation of nutrients in seeds, the transition from dormancy to germination, and seedling morphogenesis. Thus, it elucidates the multi-dimensional regulatory network mediated by miRNAs within the “establishment–preservation–manifestation” (E–P–M) framework. Specifically, miRNAs regulate embryonic development, seed maturation and dormancy release by influencing phytohormone signal transduction. They are involved in the metabolism of starch and protein to provide sufficient energy for seed germination. They also participate in activating the antioxidant system and inducing the expression of stress response genes to enhance the stress resistance of seeds. Ultimately, miRNAs affect root architecture and biomass accumulation, supporting seedling morphogenesis. It is hoped that this review can fill the theoretical gap in the regulatory mechanisms of seed vigor, and provide useful references for future theoretical research and molecular breeding.