INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

HRAC GROUP 2 (LEGACY B) RESISTANT POVERTY BROME
(Bromus sterilis)

Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

Czech Republic
INTRODUCTION POVERTY BROME
Poverty Brome (Bromus sterilis) is a monocot weed in the Poaceae family.  In Czech Republic this weed first evolved resistance to Group 2 (Legacy B) herbicides in 2017 and infests Wheat.   Group 2 (Legacy B) herbicides are known as Inhibition of Acetolactate Synthase (Inhibition of Acetolactate Synthase ).  Research has shown that these particular biotypes are resistant to propoxycarbazone-Na, pyroxsulam, and sulfometuron-methyl and they may be cross-resistant to other Group 2 (Legacy B) herbicides.

The 'Group' letters/numbers that you see throughout this web site refer to the classification of herbicides by their site of action. To see a full list of herbicides and HRAC herbicide classifications click here.

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QUIK STATS (last updated Jan 25, 2021 )

Common NamePoverty Brome
SpeciesBromus sterilis
GroupInhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Herbicidespropoxycarbazone-Na, pyroxsulam, and sulfometuron-methyl
LocationCzech Republic
Year2017
Situation(s)Wheat
Contributors - (Alphabetically)Katerina Hamouzova, Pavlína Košnarová, Jakub Mikulka, Madhab Kumar Sen, and Josef Soukup 
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NOTES ABOUT THIS BIOTYPE

GENERAL

Katerina Hamouzova

Enhanced metabolism and target gene overexpression confer resistance against acetolactate synthase‐inhibiting herbicides in Bromus sterilis
Madhab Kumar Sen  Katerina Hamouzová  Jakub Mikulka  Rohit Bharati  Pavlina Košnarová  Pavel Hamouz  Amit Roy  Josef Soukup
Pest Management Science.  First published: 17 December 2020 https://doi.org/10.1002/ps.6241

Abstract
BACKGROUND
Intensive application of acetolactate synthase (ALS)‐inhibiting herbicides has resulted in herbicide‐resistance in many weeds, including Bromus sterilis. The present study was conducted to identify the mechanisms conferring resistance to ALS‐inhibiting herbicides in a Bromus sterilis biotype.

RESULTS
Dose–response studies revealed the resistant biotype to be 288 times less sensitive to pyroxsulam than the susceptible biotype. Furthermore, experiment with a single‐dose, proved this biotype was also cross‐resistant to propoxycarbazone, iodosulfuron plus mesosulfuron and sulfosulfuron. Prior treatment with malathion, a known inhibitor of cytochrome P450s, reduced the level of resistance to pyroxsulam. No mutations were detected from the partial ALS gene sequencing. Flow cytometry and chromosome counting rejected ploidy level variation between the susceptible and resistant biotypes. Relative copy number variation ruled out gene amplification. Quantitative real‐time polymerase chain reaction (PCR) detected a significant difference in ALS gene expression between the susceptible and resistant biotypes.

CONCLUSIONS
Target gene overexpression and enhanced metabolism by cytochrome P450s are likely mechanisms of resistance to pyroxsulam in Bromus sterilis. The current findings highlight the need to monitor additional brome populations for herbicide resistance in Europe and endorse the need for alternate herbicides in integrated weed management to delay the possible evolution of herbicide resistance in these species.

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MECHANISM

Katerina Hamouzova
No already reported target site mutations were detected. But, ALS gene over-expression was found for this biotype, when compared with the sensitive biotype.

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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse trials comparing a known susceptible Poverty Brome biotype with this Poverty Brome biotype have been used to confirm resistance. For further information on the tests conducted please contact the local weed scientists that provided this information.
 
Genetics

Genetic studies on HRAC Group 2 resistant Poverty Brome have not been reported to the site.  There may be a note below or an article discussing the genetics of this biotype in the Fact Sheets and Other Literature
 
Mechanism of Resistance

Studies on the mechanism of resistance of Group 2 (Legacy B) resistant Poverty Brome from Czech Republic indicate that resistance is due to enhanced metabolism, and gene amplification.  There may be a note below or an article discussing the mechanism of resistance in the Fact Sheets and Other Literature
 
Relative Fitness

There is no record of differences in fitness or competitiveness of these resistant biotypes when compared to that of normal susceptible biotypes.  If you have any information pertaining to the fitness of Group 2 (Legacy B) resistant Poverty Brome from Czech Republic please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

KATERINA HAMOUZOVA
Weed Research Scientist
Czech University Of Agriculture In Prague
Depart. Of Agroecology And Biometeorology
Kamycka 129
Prague, 6 - Suchdol, 16521, Prague
Czech Republic
Email Katerina Hamouzova
Web   : Web Site Link
PAVLÍNA KOŠNAROVÁ
Researcher
Czech University of Life Sciences
Agroecology and Plant Production
Kamycka 129
Prague , 16500, Czech Republic
Czech Republic
Email Pavlína Košnarová
Web   : Web Site Link
JAKUB MIKULKA
Ing.
Weed Research
Department of Agroecology and Crop Production
Internacionální 1277
Prague, 16000, Prague
Czech Republic
Email Jakub Mikulka
Web   : Web Site Link
MADHAB KUMAR SEN
Ing.
Czech university of life sciences Prague
Department of Agroecology and Crop Production
Kamýcká 129
Prague 6- Suchdol, 16500
Prague, 16500, Prague
Czech Republic
Email Madhab Kumar Sen
Web   : Web Site Link
JOSEF SOUKUP
Professor
Czech University of Life Sciences Prague
Agroecology and Biometeorology
Kamycka 129
Prague 6 - Suchdol, 16521, Prague
Czech Republic
Email Josef Soukup
Web   : Web Site Link

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Czech Republic have been instrumental in providing you this information. Particular thanks is given to Katerina Hamouzova, Pavlína Košnarová, Jakub Mikulka, Madhab Kumar Sen, and Josef Soukup for providing detailed information.
Herbicide Resistant Poverty Brome Globally
(Bromus sterilis)
Herbicide Resistant Poverty Brome Globally
(Bromus sterilis)
Drag a column header and drop it here to group by that column
Herbicide Resistant Poverty Brome Globally
(Bromus sterilis)
#CountryFirstYearSituationActive IngredientsSite of Action
1 Czech RepublicCzech Republic 2017 Wheat propoxycarbazone-Na, pyroxsulam, and sulfometuron-methyl 12 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
 		289Bromus sterilisPoverty Brome18211
2 FranceFrance 2009 Wheat iodosulfuron-methyl-Na, mesosulfuron-methyl, propoxycarbazone-Na, and pyroxsulam 17 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
 		289Bromus sterilisPoverty Brome9931
3 GermanyGermany 2012 Cereals, and Rapeseed cycloxydim, and propaquizafop 18 Inhibition of Acetyl CoA Carboxylase ( HRAC Group 1 (Legacy A)
 		289Bromus sterilisPoverty Brome6741
4 GermanyGermany 2017 Wheat propoxycarbazone-Na 18 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
 		289Bromus sterilisPoverty Brome17143
5 United KingdomUnited Kingdom 2020 Wheat iodosulfuron-methyl-Na, mesosulfuron-methyl, and pyroxsulam 44 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
 		289Bromus sterilisPoverty Brome25257
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