Adam Jalaludin1, Qin Yu1, Peter Zoellner2, Roland Beffa3, Stephen B Powles1. 1. Australian Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia, WA, Australia. 2. Research Technologies Bayer AG, Industriepark Hoechst, Frankfurt, Germany. 3. Weed Resistance Research Centre, Bayer AG, Industriepark Hoechst, Frankfurt, Germany.
Abstract
BACKGROUND: An Eleusine indica population has evolved resistance to glufosinate, a major post-emergence herbicide of global agriculture. This population was analysed for target-site (glutamine synthetase) and non-target-site (glufosinate uptake, translocation and metabolism) resistance mechanisms. RESULTS: Glutamine synthetase (GS) activity extracted from susceptible (S) and resistant (R*) plants was equally sensitive to glufosinate inhibition, with IC50 values of 0.85 mm and 0.99 mm, respectively. The extractable GS activity was also similar in S and R* samples. Foliar uptake of [14 C]-glufosinate did not differ in S and R* plants, nor did glufosinate net uptake in leaf discs. Translocation of [14 C]-glufosinate into untreated shoots and roots was also similar in both populations, with 44% to 47% of the herbicide translocated out from the treated leaf 24 h after treatment. The HPLC and LC-MS analysis of glufosinate metabolism revealed no major metabolites in S or R* leaf tissue. CONCLUSIONS: Glufosinate resistance in this resistant population is not due to an insensitive GS, or increased activity, or altered glufosinate uptake and translocation, or enhanced glufosinate metabolism. Thus, target-site resistance is likely excluded and the exact resistance mechanism(s) remain to be determined.
BACKGROUND: An Eleusine indica population has evolved resistance to glufosinate, a major post-emergence herbicide of global agriculture. This population was analysed for target-site (glutamine synthetase) and non-target-site (glufosinate uptake, translocation and metabolism) resistance mechanisms. RESULTS: Glutamine synthetase (GS) activity extracted from susceptible (S) and resistant (R*) plants was equally sensitive to glufosinate inhibition, with IC50 values of 0.85 mm and 0.99 mm, respectively. The extractable GS activity was also similar in S and R* samples. Foliar uptake of [14 C]-glufosinate did not differ in S and R* plants, nor did glufosinate net uptake in leaf discs. Translocation of [14 C]-glufosinate into untreated shoots and roots was also similar in both populations, with 44% to 47% of the herbicide translocated out from the treated leaf 24 h after treatment. The HPLC and LC-MS analysis of glufosinate metabolism revealed no major metabolites in S or R* leaf tissue. CONCLUSIONS:Glufosinate resistance in this resistant population is not due to an insensitive GS, or increased activity, or altered glufosinate uptake and translocation, or enhanced glufosinate metabolism. Thus, target-site resistance is likely excluded and the exact resistance mechanism(s) remain to be determined.
Authors: Javid Gherekhloo; Pablo T Fernández-Moreno; Ricardo Alcántara-de la Cruz; Eduardo Sánchez-González; Hugo E Cruz-Hipolito; José A Domínguez-Valenzuela; Rafael De Prado Journal: Sci Rep Date: 2017-07-27 Impact factor: 4.379
Authors: Berhoz K Tahmasebi; Ricardo Alcántara-de la Cruz; Esteban Alcántara; Joel Torra; José A Domínguez-Valenzuela; Hugo E Cruz-Hipólito; Antonia M Rojano-Delgado; Rafael De Prado Journal: Front Plant Sci Date: 2018-05-28 Impact factor: 5.753