MicroRNA156: a count up timer with potential to enhance horticultural traits

MicroRNA156 (miR156), targeting a subset of SQUAMOSA PROMOTOR BINDING PROTEIN-LIKE (SPL) genes, is one of the most evolutionarily conserved microRNAs (miRNAs) in plants. miR156 is a recognized molecular marker of plant age. In addition to being an age indicator, miR156 has demonstrated strong multifunctionality in the regulation of a broad range of biological processes in horticultural plants, including vegetative growth, floral induction, fruit ripening, stress responses, and secondary metabolism. Due to its versatility and high level of conservation among phylogenetically distinct plant species, miR156 may be a powerful tool for biotechnological modification in horticultural plants. Here, we summarize the functional diversity of miR156 in horticultural plants to provide new insights for further research on the biological function and regulatory mechanism of miR156 and on how to employ miR156 to achieve the enhancement of horticultural traits.