Plant microProteins: Small but powerful modulators of plant development

MicroProteins (miPs) are small and single-domain containing proteins of less than 20 kDa. This domain allows microProteins to interact with compatible domains of evolutionary-related proteins and fine-tuning the key physiological pathways in several organisms. Since the first report of a microProtein in mice, numerous microProteins have been identified in plants by computational approaches. However, only a few candidates have been functionally characterized, primarily in Arabidopsis. The recent success of synthetic microProteins in modulating physiological activities in crops makes these proteins interesting candidates for crop engineering. Here, we comprehensively summarise the synthesis, mode of action, and functional roles of microProteins in plants. We also discuss different approaches used to identify plant microProteins. Additionally, we discuss novel approaches to design synthetic microProteins that can be used to target proteins regulating plant growth and development. We finally highlight the prospects and challenges of utilizing microProteins in future crop improvement programs.