Multiple mechanisms are involved in new imazamox-resistant varieties of durum and soft wheat

Rafael Domínguez-Mendez,Ricardo Alcántara-De La Cruz,Rafael De Prado,Raphael Aponte,Pablo T Fernández-Moreno,Antonia M Rojano-Delgado

doi:10.1038/s41598-017-13874-3

Rafael Domínguez-Mendez, Ricardo Alcántara-De La Cruz + Show 4 more

Open Access

https://doi.org/10.1038/s41598-017-13874-3

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Abstract

Weed control in wheat is one of the major goals of farmers in their efforts toward obtaining the highest crop yields for human foods. Several studies (dose-response, enzyme activity, absorption-translocation and metabolism) were conducted to characterize the resistance level of two new wheat cultivars called Rafalín (Triticum aestivum) and Antoñín (T. durum) that were obtained by conventional breeding based on Clearfield® technology; they are resistant (R) to imazamox compared to their sensitive (S) counterparts (Gazul and Simeto, respectively). The R-cultivars were 93.7-fold (Rafalín) and 43.7-fold (Antoñín) more resistant than their respective S-cultivars. The acetolactate synthase (ALS) enzyme activity revealed high resistance to imidazolinone (IMI) herbicides in R-cultivars, but no cross-resistance to other ALS herbicides was found. The Ser653Asn mutation that confers resistance to IMI herbicides was identified in the imi1 and imi2 genes of Rafalín and only in the imi1 gene of Antoñín. The 14C-imazamox absorption did not differ between the R- and S-cultivars. Imazamox was metabolized by Cyt-P450 into imazamox-hydroxyl and imazamox-glucoside in the R-cultivars, altering their translocation patterns. The differential sensitivity to imazamox between R-cultivars was due to the number of resistance genes that carry each genotype. The R-cultivars Rafalín and Antoñín could be excellent weed control tools.

Highlights

® breeding based on Clearfield technology; they are resistant (R) to imazamox compared to their sensitive (S) counterparts (Gazul and Simeto, respectively)
Since the emergence of 2,4-dichlorophenoxyacetic acid (2,4-D) in the mid-1940s4, weed control in wheat has improved thanks to the availability of a variety of selective active ingredients belonging to different chemical families, among which the following should be mentioned: 2,4-D, MCPA, MCPP, bentazon, bromoxynil, ioxynil, diclofop, fenoxaprop, clodinafop, iodosulfuron, mesosulfuron, pinoxaden, etc
Another weed control modality in crops is the use of non-selective herbicides, for which it is necessary to choose wheat varieties that are resistant to the active herbicide ingredients[5,6]

Summary

Introduction

® breeding based on Clearfield technology; they are resistant (R) to imazamox compared to their sensitive (S) counterparts (Gazul and Simeto, respectively). Since the emergence of 2,4-dichlorophenoxyacetic acid (2,4-D) in the mid-1940s4, weed control in wheat has improved thanks to the availability of a variety of selective active ingredients belonging to different chemical families, among which the following should be mentioned: 2,4-D, MCPA, MCPP, bentazon, bromoxynil, ioxynil, diclofop, fenoxaprop, clodinafop, iodosulfuron, mesosulfuron, pinoxaden, etc. Another weed control modality in crops is the use of non-selective herbicides (broad spectrum), for which it is necessary to choose wheat varieties that are resistant to the active herbicide ingredients[5,6]. IMI-resistant crops can be grown from two to a maximum of four years in the same field to reduce the risk of developing herbicide-resistant weeds[8]

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