PLANT PHYSIOLOGY , Vol 102, Issue 3 1037-1041, Copyright © 1993 by American Society of Plant Biologists
Pollen Expression of Herbicide Target Site Resistance Genes in Annual Ryegrass (Lolium rigidum)
J. Richter and S. B. Powles
Department of Crop Protection, Waite Agricultural Research Institute, University of Adelaide, P.O. Bag 1, Glen Osmond, 5064, South Australia, Australia
Herbicide resistance can occur either through target-site insensitivity or
by nontarget site-based mechanisms. Two herbicide-resistant biotypes of
Lolium rigidum Gaud., one resistant to acetolactate synthase
(ALS)-inhibiting herbicides (biotype WLR1) and the other resistant to
acetyl CoA carboxylase (ACCase)-inhibiting herbicides (biotype WLR96)
through target-site insensitivity at the whole plant and enzymic levels,
were found to express this resistance in the pollen. Pollen produced by
resistant biotypes grew uninhibited when challenged with herbicide, whereas
that from a susceptible biotype was inhibited. A third biotype, SLR31,
resistant to ACCase-inhibiting and certain ALS-inhibiting herbicides at the
whole plant level through nontarget site-based mechanisms, did not exhibit
this expression in the pollen. The technique described may form the basis
for a rapid screen for certain nuclear-encoded, target site-based
herbicide-resistance mechanisms.