Role of transporters in paraquat resistance of horseweed Conyza canadensis (L.) Cronq.

Jóri, Balázs; Soós, Vilmos; Szegő, Dóra; Páldi, Emil; Szigeti, Zoltán; Rácz, Ilona; Lásztity, Demeter

doi:10.1016/j.pestbp.2006.08.013

Cited by 30 publications

(44 citation statements)

References 34 publications

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“…Although paraquat causes rapid desiccation of leaves in susceptible plants, functional activity of leaves was confirmed using maximum quantum of photosystem II within 6 hours after treatment in a preliminary study (S1 Fig), and by other researchers [22]. The sample collections consisted of excising the youngest, fully-expanded leaf at the base of the rosette for each biological replicate, and immediately placing it in liquid nitrogen.…”

Section: Methodsmentioning

confidence: 99%

Transcription of putative tonoplast transporters in response to glyphosate and paraquat stress in Conyza bonariensis and Conyza canadensis and selection of reference genes for qRT-PCR

et al. 2017

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Herbicide resistance is a challenge for modern agriculture further complicated by cases of resistance to multiple herbicides. Conyza bonariensis and Conyza canadensis are invasive weeds of field crops, orchards, and non-cropped areas in many parts of the world. In California, USA, Conyza populations resistant to the herbicides glyphosate and paraquat have recently been described. Although the mechanism conferring resistance to glyphosate and paraquat in these species was not elucidated, reduced translocation of these herbicides was observed under experimental conditions in both species. Glyphosate and paraquat resistance associated with reduced translocation are hypothesized to be a result of sequestration of herbicides into the vacuole, with the possible involvement of over-expression of genes encoding tonoplast transporters of ABC-transporter families in cases of glyphosate resistance or cationic amino acid transporters (CAT) in cases of paraquat resistance. However, gene expression in response to herbicide treatment has not been studied in glyphosate and paraquat resistant populations. In the current study, we evaluated the transcript levels of genes possibly involved in resistance using real-time PCR. First, we evaluated eight candidate reference genes following herbicide treatment and selected three genes that exhibited stable expression profiles; ACTIN, HEAT-SHOCK-PROTEIN-70, and CYCLOPHILIN. The reference genes identified here can be used for further studies related to plant-herbicide interactions. We used these reference genes to assay the transcript levels of EPSPS, ABC transporters, and CAT in response to herbicide treatment in susceptible and resistant Conyza spp. lines. No transcription changes were observed in EPSPS or CAT genes after glyphosate or paraquat treatment, suggesting that these genes are not involved in the resistance mechanism. Transcription of the two ABC transporter genes increased following glyphosate treatment in all Conyza spp. lines. Transcription of ABC transporters also increased after paraquat treatment in all three lines of C. bonariensis. However, in C. canadensis, paraquat treatment increased transcription of only one ABC transporter gene in the susceptible line. The increase in transcription of ABC transporters after herbicide treatment is likely a stress response based on similar response observed across all Conyza lines regardless of resistance or sensitivity to glyphosate or paraquat, thus these genes do not appear to be directly involved in the mechanism of resistance in Conyza spp.

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Section: Methodsmentioning

confidence: 99%

Transcription of putative tonoplast transporters in response to glyphosate and paraquat stress in Conyza bonariensis and Conyza canadensis and selection of reference genes for qRT-PCR

et al. 2017

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“…Several studies have demonstrated that they transport herbicides and herbicide metabolites (Klein et al 2000;Schulz and Kolukisaoglu 2006). Vacuolar sequestration has been suggested as a mechanism of resistance in paraquat (Conte and Lloyd 2011;Jóri et al 2007;Lasat et al 1997).…”

Section: Introductionmentioning

confidence: 99%

A Glyphosate Resistance Mechanism in Conyza canadensis Involves Synchronization of EPSPS and ABC-transporter Genes

2015

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Horseweed, [Conyza canadensis (L.) Cronq.], has been the most frequent weed species to develop resistance to glyphosate in various parts of the world, including Greece. In order to investigate the resistance mechanism, susceptible (S) and resistant ®) populations collected from regions across Greece were studied. Real-time PCR was used to determine the expression levels of the key enzyme EPSPS and the four ABC transporter genes M10, M11, M7 and P3. The expression level of those genes was studied at early (1DAT) or late (4DAT) times after glyphosate treatment, applied at normal (720 g a.i. ha −1 ) and high (5.760 g a.i. ha −1 ) glyphosate rate. The proposed resistance mechanism was found not to be due to a point mutation at codon 106 of the EPSPS gene that regulates glyphosate metabolism (target-site resistance), but rather involved synchronization of the overexpression of EPSPS and ABC-transporter genes. This synchronization mechanism was based on (1) the time of induction and duration of gene overexpression, and (2) regulation by the initial glyphosate load.

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“…In the early studies on paraquat-resistant weeds, a sequestration mechanism was proposed, in which paraquat is prevented from diffusing into PSI, the active site of the herbicide (Fuerst et al, 1985;Fuerst and Vaughn, 1990;Preston et al, 1992;Norman et al, 1993;Chun et al, 1997a). In addition, detoxification through reduction of the ROS level or the reduced uptake of paraquat have been suggested as alternative mechanisms for paraquat resistance in weeds (Shaaltiel and Gressel, 1986;Fuerst and Vaughn, 1990;Donahue et al, 1997;Jóri et al, 2007). Consistent with the observations that paraquat resistance is correlated with the increased activity of the ROS-scavenging enzymes superoxide dismutase, ascorbate peroxidase, and glutathione reductase (Shaaltiel and Gressel, 1986;Tsugane et al, 1999;Ye and Gressel, 2000), the expression level of these genes has been associated with the paraquatresistant phenotype in several transgenic studies and in the Arabidopsis mutants rcd1 and pst1 (Bowler et al, 1991;Gupta et al, 1993;Arisi et al, 1998;Tsugane et al, 1999;Ye and Gressel, 2000;Ahlfors et al, 2004;Fujibe et al, 2004;Murgia et al, 2004).…”

mentioning

confidence: 99%

PARAQUAT RESISTANT1, a Golgi-Localized Putative Transporter Protein, Is Involved in Intracellular Transport of Paraquat

Bai

et al. 2013

Plant Physiology

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Paraquat is one of the most widely used herbicides worldwide. In green plants, paraquat targets the chloroplast by transferring electrons from photosystem I to molecular oxygen to generate toxic reactive oxygen species, which efficiently induce membrane damage and cell death. A number of paraquat-resistant biotypes of weeds and Arabidopsis (Arabidopsis thaliana) mutants have been identified. The herbicide resistance in Arabidopsis is partly attributed to a reduced uptake of paraquat through plasma membrane-localized transporters. However, the biochemical mechanism of paraquat resistance remains poorly understood. Here, we report the identification and characterization of an Arabidopsis paraquat resistant1 (par1) mutant that shows strong resistance to the herbicide without detectable developmental abnormalities. PAR1 encodes a putative L-type amino acid transporter protein localized to the Golgi apparatus. Compared with the wild-type plants, the par1 mutant plants show similar efficiency of paraquat uptake, suggesting that PAR1 is not directly responsible for the intercellular uptake of paraquat. However, the par1 mutation caused a reduction in the accumulation of paraquat in the chloroplast, suggesting that PAR1 is involved in the intracellular transport of paraquat into the chloroplast. We identified a PAR1-like gene, OsPAR1, in rice (Oryza sativa). Whereas the overexpression of OsPAR1 resulted in hypersensitivity to paraquat, the knockdown of its expression using RNA interference conferred paraquat resistance on the transgenic rice plants. These findings reveal a unique mechanism by which paraquat is actively transported into the chloroplast and also provide a practical approach for genetic manipulations of paraquat resistance in crops.

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Role of transporters in paraquat resistance of horseweed Conyza canadensis (L.) Cronq.

Cited by 30 publications

References 34 publications

Transcription of putative tonoplast transporters in response to glyphosate and paraquat stress in Conyza bonariensis and Conyza canadensis and selection of reference genes for qRT-PCR

Transcription of putative tonoplast transporters in response to glyphosate and paraquat stress in Conyza bonariensis and Conyza canadensis and selection of reference genes for qRT-PCR

A Glyphosate Resistance Mechanism in Conyza canadensis Involves Synchronization of EPSPS and ABC-transporter Genes

PARAQUAT RESISTANT1, a Golgi-Localized Putative Transporter Protein, Is Involved in Intracellular Transport of Paraquat

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