Vacuolar glyphosate-sequestration correlates with glyphosate resistance in ryegrass (Lolium spp.) from Australia, South America, and Europe: a 31P NMR investigation.
Lolium  spp., ryegrass, variants from Australia, Brazil, Chile, and Italy showing differing levels of glyphosate resistance were examined by (31)P NMR. Extents of glyphosate (i) resistance (LD(50)), (ii) inhibition of 5-enopyruvyl-shikimate-3-phosphate synthase (EPSPS) activity (IC(50)), and (iii) translocation were quantified for glyphosate-resistant (GR) and glyphosate-sensitive (GS)  Lolium multiflorum  Lam. variants from Chile and Brazil. For comparison, LD(50) and IC(50) data for  Lolium rigidum  Gaudin variants from Italy were also analyzed. All variants showed similar cellular uptake of glyphosate by (31)P NMR. All GR variants showed glyphosate sequestration within the cell vacuole, whereas there was minimal or no vacuole sequestration in the GS variants. The extent of vacuole sequestration correlated qualitatively with the level of resistance. Previous (31)P NMR studies of horseweed ( Conyza canadensis  (L.) Cronquist) revealed that glyphosate sequestration imparted glyphosate resistance. Data presented herein suggest that glyphosate vacuolar sequestration is strongly contributing, if not the major contributing, resistance mechanism in ryegrass as well.
Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States.
Xia
X
Ge
D André
DA
d'Avignon
Joseph J H
JJ
Ackerman
Alberto
A
Collavo
Maurizio
M
Sattin
Elizabeth L
EL
Ostrander
Erin L
EL
Hall
R Douglas
RD
Sammons
Christopher
C
Preston
D001315:Australia; D001692:Biological Transport; D005060:Europe; D005998:Glycine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D053209:Herbicide Resistance; D006540:Herbicides / Q000378:metabolism / Q000494:pharmacology*; D008129:Lolium / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D013020:South America; D014617:Vacuoles / Q000378:metabolism*; D000097797:Glyphosate
D005998:Glycine; D006540:Herbicides; D000097797:Glyphosate