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Multiple origins for black‐grass ( Alopecurus myosuroides Huds) target‐site‐based resistance to herbicides inhibiting acetyl‐CoA carboxylase
Author(s) -
Délye Christophe,
Straub Cécile,
Matéjicek Annick,
Michel Séverine
Publication year - 2004
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.778
Subject(s) - biology , population , genetics , allele , acetyl coa carboxylase , isoleucine , pesticide resistance , phylogenetic tree , acetolactate synthase , herbicide resistance , resistance (ecology) , gene , pyruvate carboxylase , botany , agronomy , leucine , amino acid , pesticide , biochemistry , enzyme , demography , sociology
We have investigated the process of evolution of target‐site‐based resistance to herbicides inhibiting acetyl‐CoA carboxylase (ACCase) in nine French populations of black‐grass ( Alopecurus myosuroides Huds). To date, two different ACCase resistant alleles are known. One contains an isoleucine‐to‐leucine substitution at position 1781, the second contains an isoleucine‐to‐asparagine substitution at position 2041. Using phylogenetic analysis of ACCase sequences, we showed that 1781 Leu ACCase alleles evolved from four independent origins in the nine black‐grass populations studied, while 2041 Asn ACCase alleles evolved from six independent origins. No geographical structure of black‐grass populations was revealed. This implies that these populations, although geographically distant, are, or have until recently been, connected by gene flows. Comparison of biological data obtained from herbicide sensitivity bioassay and molecular data showed that distinct resistance mechanisms often exist in a single black‐grass population. Accumulation of different resistance mechanisms in a single plant was also demonstrated. We conclude that large‐scale evolution of resistance to herbicides in black‐grass is a complex phenomenon, resulting from the independent selection of various resistance mechanisms in local black‐grass populations undergoing contrasted herbicide and agronomical selection pressures, and connected by gene flows whose parameters remain to be determined. Copyright © 2003 Society of Chemical Industry