Cross-resistance Patterns to Acetyl-CoA Carboxylase Inhibitors Associated with Different Mutations in Japanese Foxtail (Alopecurus japonicus)

Abstract

Japanese foxtail is a grass weed in eastern China. This weed is controlled by fenoxaprop-P-ethyl, one of the most common acetyl-CoA carboxylase (ACCase)-inhibiting herbicides. Some Japanese foxtail populations have developed resistance to fenoxaprop-P-ethyl, owing to target-site mutations (amino acid substitutions) located within the carboxyl transferase domain of ACCase. In the present study, three mutations were detected in three fenoxaprop-P-ethyl–resistant Japanese foxtail populations: Ile-1781-Leu in JCJT-2, Ile-2041-Asn in JZJR-1, and Asp-2078-Gly in JCWJ-3. Two copies of ACCase (Acc1-1 and Acc1-2) were identified, but mutations were detected only in Acc1-1. The derived cleaved amplified polymorphic sequence (dCAPS) method detected these mutations successfully in Japanese foxtail. The mutation frequencies in JCJT-2, JZJR-1, and JCWJ-3 were approximately 98%, 92%, and 87%, respectively. Different cross-resistance patterns to ACCase inhibitors were found in the three resistant populations. JCJT-2 (Ile-1781-Leu) and JZJR-1 (Ile-2041-Asn) showed cross-resistance to haloxyfop-R-methyl, clodinafop-propargyl, and pinoxaden, but were susceptible to clethodim. JCWJ-3 (Asp-2078-Gly) showed cross-resistance to all tested ACCase-inhibiting herbicides.

ACCase-inhibiting herbicides: mechanism of action, resistance evolution and stewardship

“…Unfortunately, only a very limited number of weeds resistant to ACCase inhibitors in South America have had the resistance mechanism elucidated such as E. indica . Cross-resistance to herbicides that act under the same MoA is usually caused by TSR mechanisms (Beckie et al, 2012;Chen et al, 2017), even though recent evidence indicates the importance of NTSR in conferring cross-resistance (Iwakami et al, 2019). Several authors have reported weeds manifesting crossresistance to different ACCase-inhibiting herbicides, including those arising from mutations Ile1781Leu, Ile2041Asn, and Trp2027Cys (Chen et al, 2017).…”

“…Cross-resistance to herbicides that act under the same MoA is usually caused by TSR mechanisms (Beckie et al, 2012;Chen et al, 2017), even though recent evidence indicates the importance of NTSR in conferring cross-resistance (Iwakami et al, 2019). Several authors have reported weeds manifesting crossresistance to different ACCase-inhibiting herbicides, including those arising from mutations Ile1781Leu, Ile2041Asn, and Trp2027Cys (Chen et al, 2017). In addition to the mutations Asp2078Gly and Cys2088Arg conferring broad spectrum of resistance on all classes of ACCase-inhibiting herbicides (Yu et al, 2007;Délye et al, 2008;Kaundun, 2010;Scarabel et al, 2011;Cruz-Hipolito et al, 2011;Gherekhloo et al, 2012;Kaundun et al, 2012), resistance levels are not solely dependent upon amino acid substitutions.…”

“…Most cross-resistance studies in grass weeds to FOPs/DIMs/DEN report TSR and consequent reduction in ACCase sensitivity to these herbicides as the underlying cause (Yu et al, 2007;Kaundun, 2014;Chen et al, 2017). A number of reports have emphasized the need to better understand and elucidate the mechanisms of NTSR-based cross-resistance, considering that it is a threat to global crop production (Yu and Powles, 2014;Shergill et al, 2017;Iwakami et al, 2019).…”

The challenge of herbicide resistance around the world: a current summary

“…ACCase resistance was first reported in Beckmannia syzigachne in 2014 and many farmers shifted to ALS inhibitors such as mesosulfuron‐methyl for the control of ACCase‐resistant weeds . This, in turn, led to multiple‐resistance in B. syzigachne and A. japonicus . Current estimates are that nearly 10% of the area in the Chinese provinces of Anhui and Jiangsu are under serious threat of resistance to both ACCase and ALS inhibitors across all key grasses, and farmers are once again shifting herbicide use to PSII inhibitors …”

“…23 This, in turn, led to multiple-resistance in B. syzigachne and A. japonicus. 21,24,25 Current estimates are that nearly 10% of the area in the Chinese provinces of Anhui and Jiangsu are under serious threat of resistance to both ACCase and ALS inhibitors across all key grasses, and farmers are once again shifting herbicide use to PSII inhibitors. 21 Maize production is spread across Asia, with even smaller countries such as Vietnam and Thailand planting over 1 × 10 6 ha annually.…”