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The First Case of Glyphosate Resistance in Johnsongrass (Sorghum halepense (L.) Pers.) in Europe

Authors :
Jose G. Vazquez-Garcia
Candelario Palma-Bautista
Antonia Maria Rojano-Delgado
Rafael De Prado
Julio Menendez
Source :
Plants, Vol 9, Iss 3, p 313 (2020)
Publication Year :
2020
Publisher :
MDPI AG, 2020.

Abstract

Six Johnsongrass populations suspected of being glyphosate resistant were collected from railways and freeways near Cordoba (SW Spain), where glyphosate is the main weed control tool. The 50% reduction in shoot fresh weight (GR50) values obtained for these six populations ranged from 550.4 to 1169 g ae ha−1, which were 4.2 to 9 times greater than the value obtained for the susceptible population. Glyphosate was equally metabolized to the same extent in both resistant and susceptible populations, with no significant differences in either 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) inhibition or basal activity. No amino acid substitutions were observed in any of the resistant populations. Slight but significant differences in glyphosate penetration were observed among some but not all of the resistant populations and for the times of incubation assayed, although these differences were not considered further. The proposed primary mechanism of resistance in these six glyphosate-resistant Johnsongrass populations is reduced herbicide translocation, because the amount of glyphosate that translocated from treated leaves to shoots and roots in the susceptible population was double that observed in the resistant populations. As glyphosate multiple resistance due to more than one mechanism is not uncommon, this is the first time that glyphosate-resistant Johnsongrass populations have been fully described for all known mechanisms.

Details

Language :
English
ISSN :
22237747
Volume :
9
Issue :
3
Database :
Directory of Open Access Journals
Journal :
Plants
Publication Type :
Academic Journal
Accession number :
edsdoj.6450ef40e8e04a31a5acb782e5a675dd
Document Type :
article
Full Text :
https://doi.org/10.3390/plants9030313