Regulation of Assimilatory Sulfate Reduction by Herbicide Safeners in Zea mays L.

Effects of the herbicide safeners N,N-diallyl-2,2-dichloroacetamide and 4-dichloroacetyl-3,4-dihydro-3-methyl-2H-1,4-benzooxazin (CGA 154281) on the contents in cysteine and glutathione, on the assimilation of (35)SO(4) (2-), and on the enzymes of assimilatory sulfate reduction were analyzed in roots and primary leaves of maize (Zea mays) seedlings. Both safeners induced an increase in cysteine and glutathione. In labeling experiments using (35)SO(4) (2-), roots of plants cultivated in the presence of safeners contained an increased level of radioactivity in glutathione and cysteine as compared with controls. A significant increase in uptake of sulfate was only detected in the presence of CGA 154281. One millimolar N,N-diallyl-2,2-dichloroacetamide applied to the roots for 6 days increased the activity of adenosine 5'-phosphosulfate sulfotransferase about 20- and threefold in the roots and leaves, respectively, compared with controls. CGA 154281 at 10 micromolar caused a sevenfold increase of this enzyme activity in the roots, but did not affect it significantly in the leaves. A significant increase in ATP-sulfurylase (EC 2.7.7.4) activity was only detected in the roots cultivated in the presence of 10 micromolar CGA 154281. Both safeners had no effect on the activity of sulfite reductase (EC 1.8.7.1) and O-acetyl-l-serine sulfhydrylase (EC 4.2.99.8). The herbicide metolachlor alone or combined with the safeners induced levels of adenosine 5'-phosphosulfate sulfotransferase, which were higher than those of the appropriate controls. Taken together these results show that the herbicide safeners increased both the level of adenosine 5'-phosphosulfate sulfotransferase activity and of the thiols cysteine and glutathione. This indicates that these safeners may be involved in eliminating the previously proposed regulatory mechanism, in which increased concentrations of thiols regulate assimilatory sulfate reduction by decreasing the activities of the enzymes involved.

[1]  C. Brunold,et al.  Regulation of Glutathione Synthesis by Cadmium in Pisum sativum L. , 1990, Plant physiology.

[2]  K. Kreuz,et al.  Effects of the safeners CGA 154281, oxabetrinil and fenclorim on uptake and degradation of metolachlor in corn (Zea mays L.) seedlings , 1989 .

[3]  C. Brunold,et al.  Regulation of Assimilatory Sulfate Reduction by Cadmium in Zea mays L. , 1988, Plant physiology.

[4]  J. W. Gronwald,et al.  Effect of herbicide antidotes on glutathione content and glutathione S-transferase activity of sorghum shoots , 1987 .

[5]  M. Suter,et al.  Effect of high and low sulfate concentrations on adenosine 5′-phosphosulfate sulfotransferase activity from Lemna minor , 1987 .

[6]  J. Richie,et al.  The determination of glutathione, cyst(e)ine, and other thiols and disulfides in biological samples using high-performance liquid chromatography with dual electrochemical detection. , 1987, Analytical biochemistry.

[7]  C. Brunold,et al.  Enzymes of assimilatory sulfate reduction in leaves of Pisum sativum: activity changes during ontogeny and in vivo regulation by H2S and cyst(e)ine , 1986 .

[8]  G. Cacco,et al.  Changes in the uptake and assimilation efficiency for sulfate and nitrate in maize hybrids selected during the period 1930 through 1975 , 1983 .

[9]  J. Casida,et al.  Dichloroacetamide herbicide antidotes enhance sulfate metabolism in corn roots , 1983 .

[10]  H. Rennenberg,et al.  Effect of N,N-diallyl-2,2-dichloroacetamide (R-25788) on efflux and synthesis of glutathione in tobacco suspension cultures , 1982 .

[11]  C. Brunold,et al.  Regulation of enzymes of assimilatory sulfate reduction in aerated cell suspension cultures of Nicotiana sylvestris , 1981 .

[12]  N. Bunce,et al.  Structure-activity relationships for antidotes to thiocarbamate herbicides in corn , 1979 .

[13]  L. Bush,et al.  Effect of R-25788 on EPTC Metabolism in Corn (Zea mays) , 1978, Weed Science.

[14]  G. Webster Herbicides: Chemistry, Degradation and Mode of Action. , 1977 .

[15]  J. Casida,et al.  Dichloroacetamide antidotes enhance thiocarbamate sulfoxide detoxification by elevating corn root glutathione content and glutathione S-transferase activity☆ , 1976 .

[16]  M. Tsang,et al.  Preparation of adenosine 5'-phosphosulfate (APS) from adenosine 3'-phosphate 5'-phosphosulfate (PAPS) prepared by an improved procedure. , 1976, Analytical biochemistry.

[17]  M. M. Bradford A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. , 1976, Analytical biochemistry.

[18]  M. Levinthal,et al.  Studies of sulfate utilization by algae. 4. Properties of a cell-free sulfate-reducing system from chlorella. , 1968, Plant physiology.

[19]  Regulation of Sulfate Assimilation in Plants1 ASSIMILATORY SULFATE REDUCTION DURING ONTOGENESIS OF PRIMARY LEAVES OF , 2022 .