MicroRNAs (miRNAs) are processed products of primary miRNAs (pri-miRNAs) and regulate the target gene expression. Though the regulatory roles of the several mature plant miRNAs have been studied in detail, the functions of other regions of the pri-miRNAs are still unrecognized. Recent studies suggest that a few pri-miRNAs may encode small peptides, miRNA-encoded peptides (miPEPs); however, the functions of these peptides have not been studied in detail. We report that the pri-miR858a of Arabidopsis thaliana encodes a small peptide, miPEP858a, which regulates the expression of pri-miR858a and associated target genes. miPEP858a-edited and miPEP858a-overexpressing lines showed altered plant development and accumulated modulated levels of flavonoids due to changes in the expression of genes associated with the phenylpropanoid pathway and auxin signalling. The exogenous treatment of the miPEP858a-edited plants with synthetic miPEP858a complemented the phenotypes and the gene function. This study suggests the importance of miPEP858a in exerting control over plant development and the phenylpropanoid pathway.

微小 RNA (miRNA) 是初级 miRNA (pri-miRNA) 的加工产物，可调节靶基因的表达。尽管已经详细研究了几种成熟植物 miRNA 的调控作用，但 pri-miRNA 其他区域的功能仍未被认识。最近的研究表明，一些 pri-miRNA 可能编码小肽，miRNA 编码的肽（miPEPs）；然而，尚未详细研究这些肽的功能。我们报道拟南芥的 pri-miR858a编码一个小肽，miPEP858a，它调节 pri-miR858a 和相关靶基因的表达。miPEP858a 编辑和 miPEP858a 过表达株系显示植物发育发生改变，并且由于与苯丙素途径和生长素信号传导相关的基因表达发生变化，黄酮类化合物的积累水平受到调节。用合成的 miPEP858a 外源处理 miPEP858a 编辑的植物补充了表型和基因功能。这项研究表明 miPEP858a 在控制植物发育和苯丙素途径方面的重要性。