Confirmation and mechanism of glyphosate resistance in tall windmill grass (Chloris elata) from Brazil

Caio A. C. G. Brunharo, Eric L. Patterson, Daniela R. Carrijo, Marcel S. C. de Melo, Marcelo Nicolai, Todd A. Gaines, Scott J. Nissen, Pedro J. Christoffoleti

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)

Abstract

BACKGROUNDOverreliance on glyphosate as a single tool for weed management in agricultural systems in Brazil has selected glyphosate-resistant populations of tall windmill grass (Chloris elata Desv.).RESULTSTwo C. elata populations, one glyphosate resistant (GR) and one glyphosate susceptible (GS), were studied in detail for a dose-response experiment and for resistance mechanism. The dose causing 50% reduction in dry weight was 620 g a.e. ha(-1) for GR and 114 g ha(-1) for GS, resulting in an R/S ratio of 5.4. GS had significantly higher maximum C-14-glyphosate absorption into the treated leaf (51.3%) than GR (39.5%), a difference of 11.8% in maximum absorption. GR also retained more C-14-glyphosate in the treated leaf (74%) than GS (51%), and GR translocated less glyphosate (27%) to other plant parts (stems, roots and root exudation) than GS (36%). There were no mutations at the Pro106 codon in the gene encoding 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). There was no difference in EPSPS genomic copy number or EPSPS transcription between GS and GR populations.CONCLUSIONBased on these data, reduced glyphosate absorption and increased glyphosate retention in the treated leaf contribute to glyphosate resistance in this C. elata population from Brazil. (c) 2015 Society of Chemical Industry
Original languageEnglish
Pages (from-to)1758-1764
Number of pages7
JournalPest Management Science
Volume72
Issue number9
DOIs
Publication statusPublished - Sept 2016
Externally publishedYes

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