High-throughput sequencing analysis reveals effects of short-term low-temperature storage on miRNA-mediated flavonoid accumulation in postharvest toon buds

Toon bud is rich in polyphenols and flavonoids, which not only have nutritional value but also have health benefits. However, the molecular mechanisms of flavonoid accumulation during storage remain unclear. In our report, small RNA libraries from toon buds were synthesized after three storage period (0, 3, and 5 days) at 4 °C. Overall, 303 homologous sequences with known microRNA (conserved miRNAs homology) and 19 putative novel miRNAs were obtained using Illumina sequencing technology. Furthermore, the potential target unigenes of these miRNAs were predicted. Of the predicted miRNAs and their target unigenes, 17 conserved miRNAs and their target unigenes were confirmed by quantitative real-time PCR (qRT-PCR). Exactly 11 miRNAs involved in the flavonoid pathway and 6 miRNAs targeting transcription factors displayed significant correlation with flavonoid accumulation in toon buds. The findings will be helpful for better understanding flavonoid accumulation in toon buds during storage.