<b>HRAC Group 2</b> <font size='2'> (Legacy B) </font> resistant Sagittaria trifolia from China

INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

HRAC GROUP 2 (LEGACY B) RESISTANT THREELEAF ARROWHEAD
(Sagittaria trifolia)

Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

China, Northeastern China

INTRODUCTION		THREELEAF ARROWHEAD
Threeleaf Arrowhead (Sagittaria trifolia) is a monocot weed in the Alismataceae family. In China this weed first evolved resistance to Group 2 (Legacy B) herbicides in 2014 and infests Rice. 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 bensulfuron-methyl, bispyribac-sodium, penoxsulam, and pyribenzoxim 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.

QUIK STATS (last updated May 01, 2018 )
Common Name	Threeleaf Arrowhead
Species	Sagittaria trifolia
Group	Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Herbicides	bensulfuron-methyl, bispyribac-sodium, penoxsulam, and pyribenzoxim
Location	China, Northeastern China
Year	2014
Situation(s)	Rice
Contributors - (Alphabetically)	Mingshan Ji
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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse, and Laboratory trials comparing a known susceptible Threeleaf Arrowhead biotype with this Threeleaf Arrowhead 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 Threeleaf Arrowhead 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 Threeleaf Arrowhead from China indicate that resistance is due to an altered target site. 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 Threeleaf Arrowhead from China please update the database.

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CONTRIBUTING WEED SCIENTISTS

MINGSHAN JI

Associate Professer Shenyang Agriculture University Plant Protection Argicultural Research and Extension Center 121 Northville Rd, Shenyang, 110161, Liaoning Province China Email Mingshan Ji

ACKNOWLEDGEMENTS
The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in China have been instrumental in providing you this information. Particular thanks is given to Mingshan Ji for providing detailed information.

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Herbicide Resistant Threeleaf Arrowhead Globally
(Sagittaria trifolia)

Country

FirstYear

Situation

Active Ingredients

Site of Action

China

2014

Rice

bensulfuron-methyl, bispyribac-sodium, penoxsulam, and pyribenzoxim

Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)

Japan

1997

Rice

bensulfuron-methyl

Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)

South Korea

2011

Rice

azimsulfuron, bensulfuron-methyl, cinosulfuron, ethoxysulfuron, halosulfuron-methyl, imazosulfuron, and pyrazosulfuron-ethyl

Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)

Literature about Similar Cases

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Satoshi, I., H. Watanabe, T. Miura, H. Matsumoto, A. Uchino.. 2014. Occurrence of sulfonylurea resistance inSagittaria trifolia, a basal monocot species, based on target-site and non-target-site resistance. Weed Biology and Management 14 : 43 - 49.

Sagittaria trifolia L. is one of the most serious weeds in paddy fields in Japan. Since the late 1990s, severe infestations ofS. trifoliahave occurred following applications of sulfonylurea herbicides in Akita prefecture. In this study, two accessions ofS. trifolia, R1 and R2, were collected from paddy fields with severe infestations and their resistance profiles were determined in comparison to a susceptible accession, S1. R1 and R2 were highly resistant to bensulfuron-methyl. R1 was also highly resistant to pyrazosulfuron-ethyl, but R2 was susceptible. Relative to S1, R1 had an amino acid substitution at the Pro_{197_{residue of acetolactate synthase (ALS), a well-known mutation that confers sulfonylurea resistance, suggesting that R1 has a target-site-based resistance (TSR) mechanism. The sequence of the ALS gene in R2 was identical to that in S1. A Southern blot analysis indicated that there was only one copy of the ALS gene in S1 and R2. These results suggest that R2 has a non-target-site-based resistance (NTSR) mechanism. R2 was moderately resistant to imazosulfuron but susceptible to thifensulfuron-methyl. R2 and S1 were susceptible to pretilachlor, benfuresate, MCPA-ethyl and bentazon. The results reveal the occurrence of two sulfonylurea-resistant biotypes ofS. trifoliathat show different mechanisms of cross-resistance to sulfonylureas related to TSR in R1 and NTSR in R2.}}.

Wu MingGen ; Zheng ChengZhi ; Li XinJia. 2010. Mutation locus of ALS gene with resistance to sulfonylurea in Sagittaria sagittrifolia L. var. longiloba T. Jiangsu Journal of Agricultural Sciences 26 : 222 - 224.

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