Identification of miRNAs and Their Target Genes Involved in the Biosynthesis of Flower Color and Scent in Rosa canina L.

Rose flowers are known for their diverse and attractive colors and scents, which are influenced by the expression of phyto-miRNAs. These are small non-coding RNAs that regulate various aspects of plant metabolism. However, the identification and functional analysis of miRNAs and their target genes involved in rose floral traits remain elusive. This study performed a comprehensive analysis of miRNAs in Rosa genus using bioinformatics and qRT-PCR approaches. It detected 36 miRNAs belonging to 20 families and found that miR5021 was the most abundant and had multiple targets in R. rugosa transcriptome. It also demonstrated that miR5021 was associated with the terpenoid biosynthesis pathway, which is responsible for producing floral volatile compounds. The negative regulation of miR5021 on five key enzymes in the terpenoid pathway (GGPS, CCD1, LIS, DXR, and DXS) in white and dark-pink flowers of R. canina was validated. The findings reveal that miR5021 plays a crucial role in modulating rose flower color and scent by regulating the terpenoid pathway and provide new insights into the molecular mechanism of rose floral traits.