Molecular Basis of Blackgrass (Alopecurus Myosuroides HUDS.) Resistance to Sulfonylurea Herbicides

Abstract

Abstract:Blackgrass biotype resistant to the mesosulfuron + iodosulfuron mixture has been found in Poland and was investigated in this study. Seedlings that survived double-dosed herbicide treatment were submitted to molecular analysis in order to explain the mechanism of resistance. Domains A and B of the acetolactate synthase gene were amplified by PCR and then sequenced. Biotypes which were both resistant and susceptible to mesosulfuron+iodosulfuron were analyzed. The comparison of the obtained sequences was made on a nucleotide and aminoacid level. The comparison revealed a substitution of proline codon to histidine codon in position 197 in each resistant plant. Mutation Pro197His is the basis of the target site resistance of A. myosuroides to sulfonylureas. There were no other mutations in als gene of the biotype that might modify the level of resistance to these herbicides.

Degradation and Metabolism of Fenoxaprop and Mesosulfuron + Iodosulfuron in Multiple Resistant Blackgrass (Alopecurus myosuroides)

“…A sequestration of the herbicide into the vacuole or the cell wall of a plant can result in resistance, when the concentration reaching the target enzyme is reduced (Heap 2014a). For the control of blackgrass two herbicide modes of action are predominant, the acetyl-coenzyme A carboxylase (ACCase) inhibitors and acetolactate-synthase (ALS) inhibitors (Cocker et al 1999;Krysiak et al 2011). Fenoxaprop (ethyl (2R)-2-{4-[(6-chloro-1,3-benzoxazol-2-yl)oxy]phenoxy} propanoate) is an ACCase inhibitor belonging to the chemical family of aryloxyphenoxypropionates (AOPPs) (Tomlin 2003).…”

Increase in resistance to sulfonylurea herbicides in Alopecurus myosuroides populations in north-eastern Poland

“…In the examined A. myosuroides populations, mutations in one or two domains of the als gene were found ( Table 2). In 2011, a mutation in domain A of the als gene was found in Poland (Krysiak et al, 2011). At position 197 of herbicide-resistant A. myosuroides, a sequence CAC instead of CCC was found, leading to the replacement of proline by histidine.…”

“…The DNA was extracted from three plants from each of the 1LD and 2LD treatments using the CTAB (cetyltrimethylammonium bromide) method (Doyle, Doyle, 1987). Primer sequences for amplification of domains A and B of the als gene were as described by Krysiak et al (2011). Genomed S.A. (Poland) was commissioned to undertake purification of the PCR product and sequencing.…”

“…The same is true in Poland. While Domaradzki and Rola (2006) discuss successful A. myosuroides eradication with mesosulfuron + iodosulfuron herbicides in the district of Opole (south-western Poland) in 2006, there were reports in 2011 of a resistant population with TSR and a mutation in the A domain of ALS (als) gen (Krysiak et al, 2011). In 2016, resistant populations were not only detected in south-western Poland but also in the north of the country, i.e.…”