Regulation of microRNAs for the production of adventitious roots

M Gleeson1, A Hayward1, C Beveridge1, B Carroll1, Y Lee2, D Ware2 and N Mitter1

  1. The University of Queensland
  2. Cold Spring Harbour Laboratories

Many horticultural industries, such as that of avocado, are constrained by woody-tree recalcitrance towards adventitious root production for clonal propagation. Consequently, it is pertinent to develop our understanding of the processes regulating adventitious rooting. MicroRNAs make excellent candidates for such studies, as they are highly conserved across the plant kingdom and are central regulators to many developmental pathways. In this study, miR160, miR167 and their AUXIN RESPONSE FACTOR regulatory targets, known to be involved in adventitious root production, have been studied in both Arabidopsis and avocado (Persea americana). New potential players in the adventitious rooting pathway involving these genes are being examined using Arabidopsis knock-out lines of transcription factors shown to interact with their promoter regions. Lines found to have significantly altered adventitious rooting phenotypes compared to wild-type controls were selected for further phenotyping and molecular characterisation of these microRNAs and their targets. Analysis of microRNA activity in avocado material undergoing traditional industry clonal propagation protocols will also be presented. Strengthening our understanding of adventitious rooting by studying microRNAs has potential to drive improvements to clonal propagation in our important horticultural crops.