Stress response and detoxification mechanisms involved in non‐target‐site herbicide resistance in sunflower

Abstract

The nature of non‐target‐site herbicide resistance (NTSR) to imidazolinone (IMI) in HA425 sunflower (Helianthus annuus L.) has not yet been fully characterized but could be related to xenobiotic metabolism. The objective of this study was to evaluate the role of cytochrome P450 monooxygenases (P450s) and other detoxification‐related proteins in NTSR in sunflower. Two sunflower inbred lines were used: HA 425, which is IMI resistant (Imisun), and HA 89, which is IMI susceptible. The growth response to the IMI herbicide imazethapyr in combination with the P450 inhibitors 1‐aminobenzotriazole (ABT) or piperonyl butoxide (PBO) was evaluated in 15‐d‐old sunflower plantlets. Roots were collected, and label‐free quantitation (LFQ) proteomic analysis was carried out to characterize the NTSR mechanisms involved in the IMI resistance trait in sunflower. The increased phytotoxicity of imazethapyr observed in the resistant line when ABT or PBO were present agrees with the hypothesis that NTSR mechanisms may contribute to herbicide resistance in sunflower. The herbicide treatment also led to changes in the levels of biotic and abiotic stress‐related proteins, glutathione S‐transferases, and cytochrome P450s, among others. Plant growth and root protein expression response to IMI herbicides in sunflower would be a combination of stress‐related and detoxification mechanisms. Understanding the basis of NTSR becomes helpful to exploit this trait in sunflower crop and to develop xenobiotic‐resistant, soil‐remediating cultivars.

Inter-chromosomal linkage disequilibrium and linked fitness cost loci associated with selection for herbicide resistance

“…We also found evidence of selection (and in some cases, differential expression) of genes involved in plant signalling and environmental stress (i.e., serine/threonine kinases, ERFs, E3-Ubiquitin Ligases, FRSs, LOG3, MDAR4, GT-3B) as well as genes involved in the shikimate acid pathway (DHD/SHD, TYRAAT2). Our results thus expand what we currently know about the detoxification NTSR mechanism in this species to include plant signalling and stress responses, both of which are either hypothesized (7) or shown to be involved in herbicide resistance (70)(71)(72)(73). While we do not currently have functional genomics resources for this species, our study using a cytochrome P450 inhibitor verifies that resistant I. purpurea individuals have the ability to detoxify the herbicide.…”

Gene expression profiling by cDNA‐AFLP reveals potential candidate genes for imazapyr‐induced male sterility in sunflower

“…Most of these TDFs were isolated from early developed (10 DAT) treated anthers (Figure 4), suggesting that not only the NTSR mechanism, but also pathways of intracellular signaling, redox processes, and proteins related to other resistance mechanisms were up regulated by the treatment in the R genotype. The constitutive expression of xenobiotic metabolism proteins has also been reported in HA425 leaves (Gil et al, 2018;Vega et al, 2020), but contrastingly, we saw here a rapid induction of these transcripts as a response to herbicide treatment in anthers of the same genotype.…”

“…Early upregulated transcripts (G.1a) exclusively detected in the R genotype included families of xenobiotic metabolism proteins such as cytochrome P450 monooxygenases, ATP-binding cassette transporter proteins, and kinases involved in protein phosphorylation, among others. These protein families have been previously reported as part of the NTSR mechanism in Imisun sunflower (Kaspar et al, 2011;Breccia et al, 2017;Gil et al, 2018;Vega et al, 2020). The NTSR mechanism prevents the xenobiotic harmful effect by reducing the number of herbicide molecules that reach the target site (Petit et al, 2010).…”

“…In other species, the NTSR processes have been related to different gene families, such as ATP‐binding cassette transporters, cytochrome P450 monooxygenase, glutathione S‐transferases, among others (Manabe et al., 2007; Yuan et al., 2007). In sunflower, some of these genes have been recently discovered as members of detoxification pathways of herbicide metabolism (Breccia et al., 2017; Balabanova et al., 2018; Gil et al., 2018; Vega et al., 2020).…”

Genome-Wide Evolutionary Analysis of Putative Non-Specific Herbicide Resistance Genes and Compilation of Core Promoters between Monocots and Dicots

“…Also, cytochromeP450 is responsible for the detoxification of noxious chemicals by facilitating NADPH and oxygen-dependent mono-oxygenation steps that help in transforming herbicides into water-soluble, herbicidal-inactive metabolites [ 59 , 60 ]. UDPGTs, in addition to GSTs, have been implicated in herbicide detoxification based on conjugation with proteins [ 61 , 62 ]. Phytohormones, secondary metabolites, and xenobiotics are among the lipophilic small molecule acceptors conjugated by UDPGT proteins [ 63 ].…”