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A psb A mutation in Kochia scoparia (L) Schrad from railroad rights‐of‐way with resistance to diuron, tebuthiuron and metribuzin
Author(s) -
Mengistu Lemma W,
Christoffers Michael J,
Lym Rodney G
Publication year - 2005
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.1079
Subject(s) - scoparia , metribuzin , biology , botany , horticulture , agronomy , weed control
Kochia [ Kochia scoparia (L) Schrad] has become resistant to many herbicides used in cropland and railroad rights‐of‐way in North Dakota and Minnesota. Kochia scoparia plants that had survived annual treatments with diuron and tebuthiuron were sampled along railroad rights‐of‐way in North Dakota and Minnesota. The samples were screened in the greenhouse for resistance to diuron, tebuthiuron, metribuzin and bromoxynil from 0.5× to 32× the recommended use rates. A resistant K scoparia accession (MN‐3R) was confirmed with resistance up to 16‐fold higher than recommended use rates for tebuthiuron and diuron and up to 4‐fold higher for metribuzin. However, the resistant K scoparia accession was susceptible to bromoxynil even at 50% of the recommended use rate. The herbicide binding region of the psb A gene fragment of eight resistant (R) and seven susceptible (S) K scoparia accessions was PCR‐amplified and sequenced for detection of mutations. The psb A gene of four R K scoparia accessions was mutated at residue 219 with substitution of isoleucine for valine (GenBank accession number AY251265). The seven S K scoparia accession sequences were wild‐type at this residue (GenBank accession number AY251266). The other four R accessions sequences showed a previously known triazine R mutation with substitution of glycine for serine at residue 264. All 15 K scoparia accessions were wild‐type at all other psb A residues within the region analyzed. Resistance to diuron, tebuthiuron and metribuzin among the railroad rights‐of‐way K scoparia is probably due to the mutation at residue 219 of the psb A gene in some plants, but due to the previously reported Ser 264 Gly substitution in other plants. Target‐site resistance associated with a change of valine to isoleucine at residue 219 of the psb A target‐site in weeds has previously been reported for Poa annua L selected in diuron‐treated grass seed fields, and for Amaranthus powelli S Wats selected in linuron‐treated carrot fields. This is the first report of the mutation in herbicide‐resistant K scoparia . Copyright © 2005 Society of Chemical Industry