The safener isoxadifen does not increase herbicide resistance evolution in recurrent selection with fenoxaprop. (December 2021)

• Record Type: Journal Article
• Authors: Gonsiorkiewicz Rigon, Carlos Alberto; Cutti, Luan; Angonese, Paula Sinigaglia; Sulzbach, Estéfani; Markus, Catarine; Gaines, Todd A.; Merotto, Aldo
• Is Part Of: Plant science. Volume 313(2021)
• Publication Date: 2021-12
• Subjects: Herbicide -- Barnyardgrass -- Low dose -- Cytochrome P450 -- Expression; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2021.111097
• Languages: English
• ISSNs: 0168-9452

Abstract

Graphical abstract: Recurrent selection of fenoxaprop-p-ethyl associated or not with the safener isoxadifen decreases the control of Echinochloa crus-galli and has the potential to evolve cross-resistance. The association of safener does not result in a faster herbicide resistance evolution, however, it upregulates a higher number of cytochrome P450 genes than fenoxaprop alone, resulting in a herbicide pressure selection of different metabolic profiles in weeds. Highlights: Addition of the safener isoxadifen does not change herbicide resistance evolution. Two cyrcles of selection with fenoxaprop decreases the control of barnyardgrass. Recurrent selection with fenoxaprop has potential for cross-resistance evolution. Selection with fenoxaprop + isoxadifen upregulated a higher number of P450 genes. The upregulated genes are important for herbicide metabolism in other systems. Abstract: Safeners are chemical compounds used to improve selectivity and safety of herbicides in crops by activating genes that enhance herbicide metabolic detoxification. The genes activated by safeners in crops are similar to the genes causing herbicide resistance through increased metabolism in weeds. This work investigated the effect of the safener isoxadifen-ethyl (IS) in combination with fenoxaprop-p-ethyl (FE) on the evolution of herbicide resistance in Echinochloa crus-galli under recurrent selection. Reduced susceptibility was observed in the progeny after recurrent selection with both FE alone and with FE + IS for two generations (G2) compared to the parental population (G0). The resistance index found in G2 after FE + IS selection was similar as when FE was used alone, demonstrating that the safener did not increase the rate or magnitude of herbicide resistance evolution. G2 progeny selected with FE alone and the combination of FE + IS had increased survival to herbicides from other mechanisms of action relative to the parental G0 population. One biotype of G2 progeny had increased constitutive expression of glutathione- S -transferase ( GST1 ) after recurrent selection with FE + IS. G2 progeny had increased expression of two P450 genes ( CYP71AK2 and CYP72A122 ) following treatment with FE, while G2 progeny had increased expression of five P450 genes ( CYP71AK2, CYP72A258, CYP81A12, CYP81A14 and CYP81A21 ) after treatment with FE + IS. Repeated selection with low doses of FE with or without the safener IS decreased E. crus-galli control and showed potential for cross-resistance evolution. Addition of safener did not further decrease herbicide sensitivity in second generation progeny; however, the recurrent use of safener in combination with FE resulted in safener-induced increased expression of several CYP genes. This is the first report using safener as an additional factor to study herbicide resistance evolution in weeds under experimental recurrent selection.