MicroRNA319-mediated gene regulatory network impacts leaf development and morphogenesis in poplar

We studied the roles of miR319a and its regulated network in leaf development in poplar. Overexpression of miR319a in Populus alba Populus glandulosa caused dwarf stature, narrow leaf blade, serrated leaf margin and light green color leaf. More layers of cells in the vascular bundle and bundle sheath of transgenic leaves were stained with phloroglucinol HCL, indicating enhanced lignification in these cells. Among the 93 putative genome-wide characterized direct targets of miR319a, three TCP (TEOSINTE BRANCHED1, CYCLOIDEA, and PROLIFERATING CELL NUCLEAR ANTIGEN BINDING FACTOR) genes were significantly downregulated in the leaves of MIR319a overexpression transgenic lines of poplar. Following that, we built a three-layered gene regulatory network mediated by miR319a using Top-down graphic gaussian model (GGM) algorithm that specifically highlights causal relationships and multiple RNA-seq data sets from MIR319a overexpression transgenics.