Cross-resistance to herbicides in annual ryegrass (Lolium rigidum). II. Chlorsulfuron resistance involves a wheat-like detoxification system

• Published in: Plant physiology (Bethesda) 1991-04, Vol.95 (4), p.1036-1043
• Main Authors: Christopher, J.T. (University of Adelaide, South Australia, Australia), Powles, S.B, Liljegren, D.R, Holtum, J.A.M
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; BIOTIPOS; BIOTYPE; Chemical control; Crop protection; Cross resistance; Enzymes; FISIOLOGIA VEGETAL; FITOTOXICIDAD; Fundamental and applied biological sciences. Psychology; HERBICIDAS; HERBICIDE; Herbicide resistance; Herbicides; LIGASAS; LIGASE; LOLIUM; Metabolism; METABOLISME; METABOLISMO; Metabolites; Mode of action; Parasitic plants. Weeds; PHYSIOLOGIE VEGETALE; Phytopathology. Animal pests. Plant and forest protection; PHYTOTOXICITE; Plants; RESISTANCE AUX PRODUITS CHIMIQUES; RESISTENCIA QUIMICA; TRITICUM AESTIVUM; VIA BIOQUIMICA DEL METABOLISMO; VOIE BIOCHIMIQUE DU METABOLISME; Weeds; Wheat
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.95.4.1036

Lolium rigidum Gaud. biotype SLR31 is resistant to the herbicide diclofop-methyl and cross-resistant to several sulfonylurea herbicides. Wheat and the cross-resistant ryegrass exhibit similar patterns of resistance to sulfonylurea herbicides, suggesting that the mechanism of resistance may be similar. Cross-resistant ryegrass is also resistant to the wheat-selective imidazolinone herbicide imazamethabenz. The cross-resistant biotype SLR31 metabolized [phenyl-U-14C]chlorsulfuron at a faster rate than a biotype which is susceptible to both diclolop-methyl and chlorsulfuron. A third biotype which is resistant to diclofop-methyl but not to chlorsulfuron metabolized chlorsulfuron at the same rate as the susceptible biotype. The increased metabolism of chlorsulfuron observed in the cross-resistant biotype is, therefore, correlated with the patterns of resistance observed in these L. rigidum biotypes. During high performance liquid chromatography analysis the major metabolite of chlorsulfuron in both susceptible and cross-resistant ryegrass coeluted with the major metabolite produced in wheat. The major product is clearly different from the major product in the tolerant dicot species, flax (Linium usitatissimum). The elution pattern of metabolites of chlorsulfuron was the same for both the susceptible and cross-resistant ryegrass but the cross-resistant ryegrass metabolized chlorsulfuron more rapidly. The investigation of the dose response to sulfonylurea herbicides at the whole plant level and the study of the metabolism of chlorsulfuron provide two independent sets of data which both suggest that the resistance to chlorsulfuron in cross-resistant ryegrass biotype SLR31 involves a wheat-like detoxification system