Target site as the main mechanism of resistance to imazamox in a Euphorbia heterophylla biotype

Rojano-Delgado, Antonia M.; Portugal, João M.; Palma-Bautista, Candelario; Alcántara-de la Cruz, Ricardo; Torra Farré, Joel; Alcántara, Esteban; Prado, Rafael de

doi:https://doi.org/10.1038/s41598-019-51682-z

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Issue date

2019-10-28

Author

Rojano-Delgado, Antonia M.

Portugal, João M.

Palma-Bautista, Candelario

Alcántara-de la Cruz, Ricardo

Torra Farré, Joel

Alcántara, Esteban

Prado, Rafael de

Suggested citation

Rojano-Delgado, Antonia M.; Portugal, João M.; Palma-Bautista, Candelario; Alcántara-de la Cruz, Ricardo; Torra Farré, Joel; Alcántara, Esteban; Prado, Rafael de; . (2019) . Target site as the main mechanism of resistance to imazamox in a Euphorbia heterophylla biotype. Scientific Reports, 2019, vol. 9, article num. 15423. https://doi.org/10.1038/s41598-019-51682-z.

Abstract

Euphorbia heterophylla is a weed species that invades extensive crop areas in subtropical regions of Brazil. This species was previously controlled by imazamox, but the continuous use of this herbicide has selected for resistant biotypes. Two biotypes of E. heterophylla from southern Brazil, one resistant

(R) and one susceptible (S) to imazamox, were compared. The resistance of the R biotype was confirmed by dose-response assays since it required 1250.2 g ai ha−1 to reduce the fresh weight by 50% versus 7.4 g ai ha−1 for the S biotype. The acetolactate synthase (ALS) enzyme activity was studied using ALS-inhibiting herbicides from five different chemical families. The R biotype required the highest concentrations to reduce this enzyme activity by 50%. A Ser653Asn mutation was found in the ALS gene of the R biotype. The experiments carried out showed that imazamox absorption and metabolism were not involved in resistance. However, greater 14C-imazamox root exudation was found in the R biotype (~70% of the total absorbed imazamox). Target site mutation in the ALS gene is the principal mechanism that explains the imazamox resistance of the R biotype, but root exudation seems to also contribute to the resistance of this biotype.

URI

http://hdl.handle.net/10459.1/67508

DOI

https://doi.org/10.1038/s41598-019-51682-z

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Scientific Reports, 2019, vol. 9, article num. 15423

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Except where otherwise noted, this item's license is described as cc-by (c) Rojano-Delgado, Antonia M. et al., 2019