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Diversity of Acetyl-Coenzyme A Carboxylase Mutations in Resistant Lolium Populations: Evaluation Using Clethodim.
- Source :
- Plant Physiology; Oct2007, Vol. 145 Issue 2, p547-558, 12p, 8 Charts, 1 Graph
- Publication Year :
- 2007
-
Abstract
- The acetyl-coenzyme A carboxylase (ACCase)-inhibiting cyclohexanedione herbicide clethodim is used to control grass weeds infesting dicot crops. In Australia clethodim is widely used to control the weed Lolium rigidum. However, clethodim-resistant Lolium populations have appeared over the last 5 years and now are present in many populations across the western Australian wheat (Triticuin aestivum) belt. An aspartate-2078-glycine (Gly) mutation in the plastidic ACCase enzyme has been identified as the only known mutation endowing clethodim resistance. Here, with 14 clethodim-resistant Lolium populations we revealed diversity and complexity in the molecular basis of resistance to ACCase-inhibiting herbicides (clethodim in particular). Several known ACCase mutations (isoleucine-1781-leucine [Leu], tryptophan-2027-cysteine [Cys], isoleucine-2041-asparagine, and aspartate-2078-Gly) and in particular, a new mutation of Cys to arginine at position 2088, were identified in plants surviving the Australian clethodim field rate (60 g ha<superscript>-1</superscript>). Twelve combination patterns of mutant alleles were revealed in relation to clethodim resistance. Through a molecular, biochemical, and biological approach, we established that the mutation 2078-Gly or 2088-arginine endows sufficient level of resistance to clethodim at the field rate, and in addition, combinations of two mutant 1781-Leu alleles, or two different mutant alleles (i.e. 1781-Leu/2027-Cys, 1781-Leu/2041-asparagine), also confer clethodim resistance. Plants homozygous for the mutant 1781, 2078, or 2088 alleles were found to be clethodim resistant and cross resistant to a number of other ACCase inhibitor herbicides including clodinafop, diclofop, fluazifop, haloxyfop, butroxydim, sethoxydim, tralkoxydim, and pinoxaden. We established that the specific mutation, the homo/heterozygous status of a plant for a specific mutation, and combinations of different resistant alleles plus herbicide rates all are important in contributing to the overall level of herbicide resistance in genetically diverse, cross-pollinated Lolium species. [ABSTRACT FROM AUTHOR]
- Subjects :
- ACETYLCOENZYME A
RYEGRASSES
ARGININE
GENETIC mutation
GRASSES
HERBICIDES
Subjects
Details
- Language :
- English
- ISSN :
- 00320889
- Volume :
- 145
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- Plant Physiology
- Publication Type :
- Academic Journal
- Accession number :
- 27257276
- Full Text :
- https://doi.org/10.1104/pp.107.105262