It has been reported that miRNAs play an important part in regulating some key genes in their own biogenesis (Xie et al. 2003; Vaucheret et al. 2004; Vaucheret 2006). For example, DCL1 is the target of miR162, and AGO1 is the target of miR168, indicating a negative role miRNAs play in their own biogenesis (Xie et al. 2003; Vaucheret et al. 2004; Liu et al. 2005; Vaucheret 2006). Recent studies also discoverd that the primary transcripts of trans-acting siRNA (tasiRNA) TAS1, TAS2, TAS3 and TAS4 are cleaved by miR173-AGO1, miR390-AGO7 and miR828-AGO1, demonstrating that miRNAs are also involved in the regulation of siRNAs (Allen et al. 2005; Montgomery et al. 2008a, b; Cuperus et al. 2011).

Switchgrass MiRNAs