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. 2021 Aug 19;10(8):1703.
doi: 10.3390/plants10081703.

Point Mutations and Cytochrome P450 Can Contribute to Resistance to ACCase-Inhibiting Herbicides in Three Phalaris Species

José G Vázquez-García  1 , Joel Torra  2 , Candelario Palma-Bautista  1 , Ricardo Alcántara-de la Cruz  3 , Rafael De Prado  1
Affiliations

Point Mutations and Cytochrome P450 Can Contribute to Resistance to ACCase-Inhibiting Herbicides in Three Phalaris Species

José G Vázquez-García et al. Plants (Basel). .

Abstract

Species of Phalaris have historically been controlled by acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides; however, overreliance on herbicides with this mechanism of action has resulted in the selection of resistant biotypes. The resistance to ACCase-inhibiting herbicides was characterized in Phalaris brachystachys, Phalaris minor, and Phalaris paradoxa samples collected from winter wheat fields in northern Iran. Three resistant (R) biotypes, one of each Phalaris species, presented high cross-resistance levels to diclofop-methyl, cycloxydim, and pinoxaden, which belong to the chemical families of aryloxyphenoxypropionates (FOPs), cyclohexanediones (DIMs), and phenylpyrazolines (DENs), respectively. The metabolism of 14C-diclofop-methyl contributed to the resistance of the P. brachystachys R biotype, while no evidence of herbicide metabolism was found in P. minor or P. paradoxa. ACCase in vitro assays showed that the target sites were very sensitive to FOP, DIM, and DEN herbicides in the S biotypes of the three species, while the R Phalaris spp. biotypes presented different levels of resistance to these herbicides. ACCase gene sequencing confirmed that cross-resistance in Phalaris species was conferred by specific point mutations. Resistance in the P. brachystachys R biotype was due to target site and non-target-site resistance mechanisms, while in P. minor and P. paradoxa, only an altered target site was found.

Keywords: NTSR mechanisms; TSR mechanisms; herbicide resistance; metabolism; resistance mechanisms.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Basal ACCase activity (absence of herbicides) in R and S biotypes of Phalaris species expressed as nmol HCO3 per mg of total soluble protein (TSP) per hour.
Figure 2
Figure 2
Amino acid substitutions in the A and B regions of the carboxyl transferase (CT) domain of the homomeric chloroplast acetyl CoA carboxylase (ACCase) gene in susceptible (S) and resistant (R) Phalaris biotypes.
See this image and copyright information in PMC

References

    1. Alcantara C., Jimenez-Hidalgo M.J., Saavedra M. Responses of Phalaris minor Rezt. and Phalaris brachystachys to different levels of soil water availability. Span. J. Agric. Res. 2010;8:1074–1083. doi: 10.5424/sjar/2010084-1402. - DOI
    1. Keshavarzi M., Khaksar M., Ghadam P. Biosystematic study of Phalaris L. species (Poaceae) in Iran. Taxon. Biosyst. 2013;4:25–30.
    1. Mirkamali H. Control of Phalaris brachystachys and Phalaris minor in wheat grown in northern Iran. Proc. Br. Crop Prot. Conf. Weeds. 1987;2:407–412.
    1. Heap I. International Survey of Herbicide Resistant Weeds. [(accessed on 15 July 2021)];2021 Available online: http://www.weedscience.org/
    1. Gherekhloo J., Rashed Mohassel M.H., Mahalati M.N., Zand E., Ghanbari A., Osuna M.D., De Prado R. Confirmed resistance to aryloxyphenoxypropionate herbicides in Phalaris minor populations in Iran. Weed Biol. Manag. 2011;11:29–37. doi: 10.1111/j.1445-6664.2011.00402.x. - DOI

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