miR158 negatively regulate phasiRNA biogenesis from a pseudogene in A. thaliana

miRNAs are a class of small RNAs and play vital roles in gene regulation either by post-transcriptional cleavage or by translational inhibition. A few miRNAs trigger biogenesis of phased small-interfering RNAs (phasiRNA), another class of small RNAs those act in trans. Here we identified a novel pathway where miRNA suppresses phasiRNA biogenesis. We show miR158 targets a pseudogene in A. thaliana and its expression is reduced or negligible in western Himalayan populations. However, it leads to enhanced biogenesis of phasiRNAs from miR158 target template triggered by TAS2 derived siRNA. The negative regulation of phasiRNA biogenesis by miR158 implicates larger role of both miRNAs and pseudogenes in plants.