Unraveling the mechanism of resistance in a glufosinate-resistant Palmer amaranth (<i>Amaranthus palmeri</i>) accession

Abstract Glufosinate resistance in Palmer amaranth ( Amaranthus palmeri S. Watson) was recently detected three accessions from Arkansas, USA. is the first and only broadleaf weed species resistant to this herbicide, mechanism still unclear. A previous study characterized glufosinate level Arkansas. highly glufosinate-resistant accession further used investigate conferring A. . Experiments were designed sequence herbicide target enzyme cytosolic chloroplastic glutamine synthetase isoforms GS1 GS2 , respectively) quantify copy number expression. Absorption, translocation, metabolism of using 14 C-labeled also evaluated susceptible accessions. The had an increase expression compared with plants. All showed one no differences No mutations identified or Absorption (54% 60%) (13% 21%) not different between glufosinate-susceptible Most residues (94% 98%) present treated leaf. translocation tissues above leaf roots among However, below (not including roots) greater (2%) (less than 1%) findings paper strongly indicate that gene amplification increased are mechanisms investigated. Thus far, additional observed, but investigations ongoing.