MicroRNAs (miRNAs) are short regulatory RNAs that regulate many biological processes through cleavage of target mRNA, thereby suppressing translation. They are processed from primary transcripts called primary miRNAs (pri-miRNAs). The miR172c is an important non-coding RNA, which functions in nodulation regulation. It was demonstrated to promote nodule formation by transcriptionally repressing its target Nodule Number Control1 (NNC1), the protein product, which acts as a transcriptional repressor of the early nodulin gene ENOD40. Overexpressing miR172c significantly upregulates the expression level of ENOD40, ultimately giving rise to a phenotypic change of increased nodule number. These regulatory interactions have been confirmed at the post-translational level. Most interestingly, a number of recent studies revealed that some pri-miRNAs also encode small functional peptides, termed miRNA peptides (miPEPs). Whether pri-miR172c has a similar regulatory coding function remains unknown. Through bioinformatic analysis, we identified ten small open reading frames from pri-miR172c and found that their encoded amino acid sequences share a certain level of conservation with other legume species. Meanwhile, we are investigating their promoter regions for essential cis-regulatory elements that are critical for pri-miR172c translation. We selected six of these ORFs for further tissue-specific promoter activity analyses, with preliminary results showing that some exhibit nodule primordium-specific expression patterns. Preliminary results regarding the prediction validation and the implicated functions of miPEPs will be presented.