Possible involvement of glutathione S-transferases in imazamox detoxification in an imidazolinone-resistant sunflower hybrid

Abstract

The resistance of crops to herbicides can be due to target site based resistance or non-target site based resistance mechanisms or a combination of both. In non-target site resistance, the detoxification efficiency plays a major role by involvement of enzymes such as P450s, GTs, GSTs and ABC transporters. The resistance of the first commercial Clearfield sunflower hybrids (Imisun trait) to herbicides of imidazolinone group is based on a combination of both types of resistance. The target site resistance consists of a mutation in Ahasl1 gene, encoding the synthesis of the AHAS enzyme. The non-target site resistance is supposed to be due to intensified herbicide disposal and is not fully understood. The objective of this study was to detect the fast response of the glutathione-mediated detoxification system in IMI-R and IMI-S sunflower hybrids to the herbicide imazamox and to study the possible participation of GSTs in the enhancement of the hybrids' tolerance. The obtained results allow to presume that GSTs are involved in imazamox detoxification in the sunflower Imisun trait and thus contributing to its non-target site resistance.

Partial Male Sterility in Imisun Sunflower: Imazapyr Treatment in Advanced Vegetative Stages Decreases Pollen Yield and Alters ahas Gene Expression

“…The Imr2 locus has been related to a non-target-site resistance mechanism associated with P450s isozymes (Breccia et al, 2017). Recently, Balabanova et al (2018) showed that GSTs enzymes are also involved in imazamox detoxification in the sunflower Imisun trait and thus contribute to its non-target-site resistance. Thus, different behaviors between genotypes were expected, as this mechanism is only present in the R genotype.…”

Transcript Profiling of Non‐Target‐Site Imidazolinone Resistance in Imisun Sunflower

“…Moreover, the increased susceptibility to imazapyr after P450 inhibitor treatments suggested that several P450 isozymes were related to herbicide resistance in Imisun cultivars (Breccia et al, 2017). In addition, an involvement of a detoxification system mediated by GSTs was detected in Imisun sunflower hybrids treated with the herbicide imazamox (Balabanova et al, 2017).…”

“…Afterward, the activated xenobiotic is conjugated using thiols or sugars and actively transported into the vacuole or extracellular space, where it is finally degraded (Yuan et al, 2007). Few studies have described the participation of these gene families in metabolizing herbicides in the Helianthus genera, and they were particularly focused on P450s (Didierjean et al, 2002;Kaspar et al, 2011;Breccia et al, 2017) and GSTs (Balabanova et al, 2017). Few studies have described the participation of these gene families in metabolizing herbicides in the Helianthus genera, and they were particularly focused on P450s (Didierjean et al, 2002;Kaspar et al, 2011;Breccia et al, 2017) and GSTs (Balabanova et al, 2017).…”

“…Currently, several gene families have been related to these metabolic resistance processes: cytochrome P450 monooxygenases (P450s), glutathione S-transferases (GSTs), glycosyltransferases, and ATP-binding cassette (ABC) transporters, among others (Manabe et al, 2007;Yuan et al, 2007;Délye, 2012). Few studies have described the participation of these gene families in metabolizing herbicides in the Helianthus genera, and they were particularly focused on P450s (Didierjean et al, 2002;Kaspar et al, 2011;Breccia et al, 2017) and GSTs (Balabanova et al, 2017).…”

Evidence of accelerated and altered pollen development after Imazapyr treatment in resistant sunflower

“…The AHAS enzyme, also known as acetolactate synthase (ALS), catalyzes the first step in the biosynthetic pathway of the branched chain amino acids (BCAA). A mechanism related to nontargetsite resistance was associated to Imr2 (Breccia et al 2017;Balabanova et al 2018).…”