Genome-wide computational prediction and experimental validation of quinoa (Chenopodium quinoa) microRNAs

MicroRNAs (miRNAs) are highly conserved, endogenous, short (21-24 nucleotides), non-coding RNA molecules that play significant roles in post-transcriptional gene silencing by directing target mRNA cleavage or translational inhibition. Nonetheless, highly nutritious "super grain" quinoa (Chenopodium quinoa) is an extreme abiotic stress tolerant Andean seed crop of many potential uses, with outstanding protein quality and a load of vitamins, minerals, as well as flavonoid antioxidants. In this study, applying genome-wide in silico approaches (referring to the recently published quinoa genome) and following a set of stringent filtering measures, a total of 22 potentially conserved microRNAs belonging to 18 families were characterized from quinoa and 11 randomly selected putative microRNAs (cqu-miR160a, cqu-miR162a, cqu-miR164a, cqu-miR166b, cqu-miR167a, cqu-miR172a, cqu-miR319a, cqu-miR390a, cqu-miR393a, cqu-miR394a, and cqu-miR398b) were validated successfully by RT-PCR. Using the psRNATarget tool, a sum of 59 potential miRNA targets, mostly transcription factors, were identified that are involved in biosynthesis, metabolic processes, and signal transduction. Among the detected targets, six target transcripts (F-Box proteins, TCP, MYB, WD protein, NAC, and CSD) were reported to have specific roles in both flavonoids biosynthesis and stress response signaling in some plants. To the best of our knowledge, this is the first report of quinoa microRNAs and their targets.