title: Overexpression of a specific soybean GmGSTU4 isoenzyme improves diphenyl ether and chloroacetanilide herbicide tolerance of transgenic tobacco plants.
abstract: Plant glutathione transferases (GSTs) superfamily consists of multifunctional enzymes and forms a major part of the plants herbicide detoxification enzyme network. The tau class GST isoenzyme GmGSTU4 from soybean, exhibits catalytic activity towards the diphenyl ether herbicide fluorodifen and is active as glutathione-dependent peroxidase (GPOX). Transgenic tobacco plants of Basmas cultivar were generated via Agrobacterium transformation. The aim was to evaluate in planta, GmGSTU4's role in detoxifying the diphenyl ether herbicides fluorodifen and oxyfluorfen and the chloroacetanilides alachlor and metolachlor. Transgenic tobacco plants were verified by PCR and Southern blot hybridization and expression of GmGSTU4 was determined by RT-PCR. Leaf extracts from transgenic plants showed moderate increase in GST activity towards CDNB and a significant increase towards fluorodifen and alachlor, and at the same time an increased GPOX activity towards cumene hydroperoxide. GmGSTU4 overexpressing plants when treated with 200 μM fluorodifen or oxyfluorfen exhibited reduced relative electrolyte leakage compared to wild type plants. Moreover all GmGSTU4 overexpressing lines exhibited significantly increased tolerance towards alachlor when grown in vitro at 7.5 mg/L alachlor compared to wild type plants. No significant increased tolerance was observed to metolachlor. These results confirm the contribution of this particular GmGSTU4 isoenzyme from soybean in the detoxification of fluorodifen and alachlor, and provide the basis towards the development of transgenic plants with improved phytoremediation capabilities for future use in environmental cleanup of herbicides.
authors.affiliation: Department of Genetics and Plant Breeding, School of Agriculture, Aristotle University of Thessaloniki, P.O. Box 261, Thessaloniki GR-54124, Greece.
authors.forename: Kostantinos
authors.initials: K
authors.lastname: Benekos
authors.forename: Christos
authors.initials: C
authors.lastname: Kissoudis
authors.forename: Irini
authors.initials: I
authors.lastname: Nianiou-Obeidat
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Labrou
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Madesis
authors.forename: Mary
authors.initials: M
authors.lastname: Kalamaki
authors.forename: Antonis
authors.initials: A
authors.lastname: Makris
authors.forename: Athanasios
authors.initials: A
authors.lastname: Tsaftaris
mesh_terms: D000081:Acetamides / Q000378:metabolism* / Q000494:pharmacology; D005982:Glutathione Transferase / Q000096:biosynthesis* / Q000235:genetics; D008658:Inactivation, Metabolic; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics; D010641:Phenotype; D010647:Phenyl Ethers / Q000378:metabolism* / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D030262:Soybean Proteins / Q000096:biosynthesis* / Q000235:genetics; D014026:Nicotiana / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development
chemical_list: D000081:Acetamides; D007527:Isoenzymes; D010647:Phenyl Ethers; D030262:Soybean Proteins; C031538:phenyl ether; C078188:2-chloro-N-(ethoxymethyl)-N-(2-methyl-6-(trifluoromethyl)phenyl)acetamide; D005982:Glutathione Transferase