Micro Proteins: A Novel Approach for Crop Improvement

Abstract— Microproteins (miPs) are small proteins, typically under 20 kDa, that play crucial roles in protein-protein interactions by forming non-functional complexes, thus regulating targets in a dominant-negative manner. They are classified into cis-miPs, which arise from mRNA isoforms through alternative splicing or translation, and trans-miPs, which evolve from genome amplification and domain loss. miPs can interact homotypically with similar domains or heterotypically with compatible but non-identical domains, potentially broadening their regulatory functions. Initially identified in mice, numerous miPs have since been discovered in plants, particularly through computational methods, although few have been functionally characterized, with a focus on Arabidopsis thaliana. Recent advances in synthetic microproteins have demonstrated their potential in crop engineering by modulating physiological processes. In plants, miPs have been linked to various functions, including epidermal cell patterning during root hair and trichome development, light responses, leaf development, pigment biosynthesis, and floral development. The identification and characterization of miPs in economically important plants have been facilitated by improved genomic and molecular tools, highlighting their significance in plant physiology and agricultural applications.