Enhanced tolerance of transgenic poplar plants overexpressing γ‐glutamylcysteine synthetase towards chloroacetanilide herbicides
Open Access
- 1 May 2001
- journal article
- research article
- Published by Oxford University Press (OUP) in Journal of Experimental Botany
- Vol. 52 (358) , 971-979
- https://doi.org/10.1093/jexbot/52.358.971
Abstract
A wild‐type poplar hybrid and two transgenic clones overexpressing a bacterial γ‐glutamylcysteine synthetase in the cytosol or in the chloroplasts were exposed to the chloroacetanilide herbicides acetochlor and metolachlor dispersed in the soil. The transformed poplars contained higher γ‐glutamylcysteine and glutathione (GSH) levels than wild‐type plants and therefore it was supposed that they would have an elevated tolerance towards these herbicides, which are detoxified in GSH‐dependent reactions. Phenotypically, the transgenic and wild‐type plants did not differ. The growth and the biomass of all poplar lines were markedly reduced by the two chloroacetanilide herbicides. However, the decrease of shoot and root fresh weights caused by the herbicides was significantly smaller in the transgenic than in wild‐type plants. In addition, the growth rate of poplars transformed in the cytosol was reduced to a significantly lesser extent than that of wild‐type plants following herbicide treatments. The effects of the two herbicides were similar. Herbicide exposures markedly increased the levels of γ‐glutamylcysteine and GSH in leaves of each poplar line. The increase in the foliar amounts of these thiols was stronger in the transgenic lines than in the wild type, particularly in the upper leaves. Considerable GST activities were detected in leaves of all poplar plants. Exposure of poplars to chloroacetanilide herbicides resulted in a marked induction of GST activity in upper leaf positions but not in middle and lower leaves. The extent of enzyme induction did not differ significantly between transgenic and wild‐type poplars. Although the results show that the transgenic poplar lines are good candidates for phytoremediation purposes, the further improvement of their detoxification capacity, preferably by transformation using genes encoding herbicide‐specific GST isoenzymes, seems to be the most promising way to obtain plants suitable for practical application.Keywords
This publication has 34 references indexed in Scilit:
- Phytochelatins and Their Roles in Heavy Metal DetoxificationPlant Physiology, 2000
- Responses to cadmium in leaves of transformed poplars overexpressing Γ‐glutamylcysteine synthetasePhysiologia Plantarum, 2000
- Plant glutathione S-transferases: enzymes with multiple functions in sickness and in healthPublished by Elsevier ,2000
- Elevated Glutathione Biosynthetic Capacity in the Chloroplasts of Transgenic Tobacco Plants Paradoxically Causes Increased Oxidative StressPlant Cell, 1999
- The Spatial and Temporal Distributions of Spheroidal Carbonaceous Fly-Ash Particles (SCP) in the Sediment Records of European Mountain LakesWater, Air, & Soil Pollution, 1999
- Local and Systemic Responses of Antioxidants to Tobacco Mosaic Virus Infection and to Salicylic Acid in Tobacco (Role in Systemic Acquired Resistance)Plant Physiology, 1997
- Uptake and Metabolism of Atrazine by Poplar TreesEnvironmental Science & Technology, 1997
- Enhanced degradation of a mixture of three herbicides in the rhizosphere of a herbicide-tolerant plantChemosphere, 1994
- Cysteine, γ‐glutamyl‐cysteine and glutathione contents of spinach leaves as affected by darkness and application of excess sulfur. II. Glutathione accumulation in detached leaves exposed to H2S in the absence of light is stimulated by the supply of glycine to the petiolePhysiologia Plantarum, 1990
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976