PLEIOTROPIC REGULATORY LOCUS 1 is required for root to shoot transmission of RNA silencing in Arabidopsis embryos and seedlings

MH Turner1,2, NR Gursanscky1, C Taochy1, J Cao1, M Coleman1, L McKeough1, SJ Fletcher1, K Kazan2 and BJ Carroll1

  1. School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
  2. CSIRO Agriculture and Food, QBP, St Lucia, QLD, 4072, Australia

Post-transcriptional gene silencing (PTGS) of transgenes is graft-transmissible and acts systemically throughout plants. A forward genetic screen identified one mutant, rtp1-1, that showed delayed onset of systemic PTGS and a variety of developmental abnormalities. We used map-based cloning to identify rtp1-1, and found it to be a new allele of the previously described PLEIOTROPIC REGULATORY LOCUS 1 (PRL1). Recently, it was reported that PRL1 is an RNA binding protein required for the accumulation of endogenous small regulatory RNAs in Arabidopsis shoot tissues or whole plants. PRL1 is a member of a two-gene family in Arabidopsis, and we also characterized the prl2-1 T-DNA insertion mutant and the prl1(rtp1-1) prl2-1 double mutant for defects in systemic RNA silencing. PRL1 is also a core component of a plant defense pathway required for plant innate immunity, and we have characterized prl1, prl2 and mutants defective in small regulatory RNA (sRNA) biogenesis for an altered response to the root-rot pathogen Fusarium oxysporum (Fo).