Identification and Characterization of microRNA319a and Its Putative Target Gene, , in the Bioenergy Grass Switchgrass ().

Due to its high biomass yield, low environmental impact, and widespread adaptability to poor soils and harsh conditions, switchgrass ( L.), a warm-region perennial herbaceous plant, has attracted much attention in recent years. However, little is known about microRNAs (miRNAs) and their functions in this bioenergy grass. Here, we identified and characterized a miRNA gene, , encoding microRNA319a in switchgrass. Transgenic rice lines generated by overexpressing the precursor gene exhibited broader leaves and delayed flowering compared with the control. Gene expression analysis indicated at least four putative target genes were downregulated. Additionally, we cloned a putative target gene () of from switchgrass. PvPCF5, a TCP transcription factor, is a nuclear-localized protein with transactivation activity and control the development of leaf. Our results suggest that and its target genes may be used as potential genetic regulators for future switchgrass genetic improvement.