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Target and Nontarget Resistance Mechanisms Induce Annual Bluegrass (Poa annua) Resistance to Atrazine, Amicarbazone, and Diuron
Published online by Cambridge University Press: 20 January 2017
Abstract
Annual bluegrass is a weed species in turfgrass environments known for exhibiting resistance to multiple herbicide modes of action, including photosystem II (PSII) inhibitors. To evaluate populations of annual bluegrass for susceptibility to PSII inhibitors of varied chemistries, populations were treated with herbicides from triazolinone, triazine, and substituted urea families: amicarbazone, atrazine, and diuron, respectively. Sequencing of the psbA gene confirmed the presence of a Ser264 to Gly amino acid substitution within populations that exhibited resistance to both atrazine and amicarbazone. A single biotype, DR3, which lacked any previously reported psbA gene point mutation, exhibited resistance to diuron, atrazine, and amicarbazone. DR3 had a significantly lower rate of absorption and translocation of atrazine and had enhanced atrazine metabolism when compared with both the Ser264 to Gly resistant mutant and susceptible biotypes. We thus report possible nontarget mechanisms of resistance to PSII-inhibiting herbicides in annual bluegrass.
Poa annua es una especie de maleza en ambientes de céspedes conocida por presentar resistencia a múltiples modos de acción de herbicidas, incluyendo inhibidores del fotosistema II (PSII). Para evaluar la susceptibilidad de poblaciones de P. annua a inhibidores PSII de diferentes características químicas, varias poblaciones fueron tratadas con herbicidas de las familias triazolinone, triazine, y urea sustituidas: amicarbazone, atrazine, y diuron, respectivamente. La secuenciación del gen psbA confirmó la presencia de una sustitución de amino ácidos de Ser264 a Gly en poblaciones que presentaron resistencia a atrazine y amicarbazone. Un solo biotipo, DR3, el cual carecía de cualquier reporte previo de mutaciones puntuales en el gen psbA, presentó resistencia a diuron, atrazine, y amicarbazone. DR3 tuvo una tasa de absorción y translocación significativamente menor de atrazine y un mayor metabolismo de atrazine cuando se comparó con biotipos resistentes con la mutación Ser264 a Gly y con biotipos susceptibles. De esta forma, reportamos posibles mecanismos de resistencia a herbicidas inhibidores de PSII en P. annua que no involucran el sitio activo.
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- Copyright © Weed Science Society of America
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