MicroRNA miR396, GRF transcription factors and GIF co-regulators: a conserved plant growth regulatory module with potential for breeding and biotechnology.

Multicellular life relies on complex regulatory mechanisms ensuring proper growth and development. In plants, these mechanisms construct a body plan that is both reproducible, and highly flexible for adaptation to different environmental conditions. A crucial regulatory module - consisting of microRNA miR396, GROWTH REGULATING FACTORS (GRFs) and GRF-INTERACTING FACTORS (GIFs) - has been shown to control growth of multiple tissues and organs in a variety of species. Especially in the last few years, research has expanded our knowledge of miR396-GRF/GIF function to crops, where it affects agronomically important traits, and highlighted its role in coordinating growth with endogenous and environmental factors. Special properties make the miR396-GRF/GIF system highly efficient in growth regulation and a promising target for improving plant yield.