Molecular basis of cross-resistance to acetohydroxy acid synthase-inhibiting herbicides in Sagittaria trifolia L

• Published in: Pesticide biochemistry and physiology Vol. 173; p. 104795
• Main Authors: Sun, Zhonghua, Li, Xiuwei, Wang, Kai, Zhao, Ping, Li, Jing, Wang, Weijing, Ahmed, Maqsood, Shafi, Jamil, Zhao, Bochui, Fu, Danni, Zhu, He, Ji, Mingshan
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.03.2021
• Subjects: Acetohydroxy acid synthase; Acetolactate Synthase - genetics; China; Cross-resistance, BCAAs, Sagittaria trifolia L; Herbicide Resistance - genetics; Herbicides - pharmacology; Mutation; Resistance mutation; Sagittaria; China; Resistance mutation; Acetohydroxy acid synthase; Cross-resistance, BCAAs, Sagittaria trifolia L
• ISSN: 0048-3575; 1095-9939
• DOI: 10.1016/j.pestbp.2021.104795

Acetohydroxy acid synthase (AHAS)-inhibiting herbicides are one of the most commonly used herbicides for controlling the growth of Sagittaria trifolia L. in paddy fields in Northeastern China. In this study, we collected five suspected resistant populations of S. trifolia (R1-R5) from three different provinces of Northeastern China. The results of whole-plant bioassays revealed that those populations showed high level of resistance to bensulfuron-methyl with resistance index (GR50 R/S) ranging from 39.90 to 88.50. The results of AHAS-activity assays were consistent with the results of the whole-plant bioassays. The AHAS gene analysis showed that R2 and R3 populations contained Pro-197-Leu mutations that were highly resistant to penoxsulam; R1 and R4 populations contained Pro-197-Ser mutations that were highly resistant to bispyribac‑sodium; R5 population contained Trp-574-Leu mutation that showed high resistance to IMI, PT, PTB and SU herbicides. The AHAS with resistance mutations showed less sensitivity to feedback inhibition by BCAAs and R genotypes had increased free BCAAs [Display omitted] •Different mutations confer resistance to different kinds of AHAS inhibiting herbicides in Sagittaria trifolia population.•AHAS enzyme assays indicated that altered AHAS sensitivity was responsible mainly for cross resistance patterns.•Difference in BCAAs feedback inhibition was observed in AHAS mutations of S. trifolia.