miRNA-encoded peptide, miPEP858, regulates plant growth and development in Arabidopsis

MicroRNAs (miRNAs), small non-coding endogenous RNAs, are processed product of primary miRNAs (pri-miRNAs) and regulate target gene expression. pri-miRNAs have also been reported to encode small peptides, miRNA-Encoded Peptides (miPEPs). Though regulatory role of miPEPs has been speculated, no detailed study has been carried out to elucidate their function through developing knock-out mutants. Here, we report that pri-miR858a of Arabidopsis thaliana encodes a small peptide (miPEP858a) which regulates the expression of pri-miR858a leading to modulation in the expression of target genes involved in the plant growth and development as well as phenylpropanoid pathway. CRISPR-based miPEP858a-edited plants developed phenotypes similar to that of mature miR858-edited plants suggesting crucial role of miPEP858a in mediating miR585a function. miPEP858a-edited and miPEP858a overexpressing lines altered plant development and accumulated modulated levels of flavonoids due to changes in expression of associated genes. Exogenous treatment of synthetic-miPEP858a to the miPEP858a-edited plants complemented phenotypes and the gene function suggesting a significant role of miPEP858a in controlling the miR858 function and plant development. One sentence summary Small peptide, miPEP858a, encoded by primary miRNA for miR858a regulates plant growth, development and flavonoid biosynthesis The authors responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors