Herbicide Safener-Binding Protein of Maize¹
Purification, Cloning, and Expression of an Encoding cDNA

John S. Scott-Craig², John E. Casida, Lisa Poduje, and Jonathan D. Walton^{2, *}

Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824 (J.S.S.-C., L.P., J.D.W.); and Environmental Chemistry and Toxicology Laboratory, Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720-3112 (J.E.C.)

Dichloroacetamide safeners protect maize (Zea mays L.) against injury from chloroacetanilide and thiocarbamate herbicides. Etiolated maize seedlings have a high-affinity cytosolic-binding site for the safener [³H](R,S)-3-dichloroacetyl-2,2,5-trimethyl-1,3-oxazol-idine ([³H]Saf), and this safener-binding activity (SafBA) is competitively inhibited by the herbicides. The safener-binding protein (SafBP), purified to homogeneity, has a relative molecular weight of 39,000, as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and an isoelectric point of 5.5. Antiserum raised against purified SafBP specifically recognizes a 39-kD protein in etiolated maize and sorghum (Sorghum bicolor L.), which have SafBA, but not in etiolated wheat (Triticum aestivum L.), oat (Avena sativa L.), barley (Hordeum vulgare L.), tobacco (Nicotiana tabacum L.), or Arabidopsis, which lack SafBA. SafBP is most abundant in the coleoptile and scarcest in the leaves, consistent with the distribution of SafBA. SBP1, a cDNA encoding SafBP, was cloned using polymerase chain reaction primers based on purified proteolytic peptides. Extracts of Escherichia coli cells expressing SBP1 have strong [³H]Saf binding, which, like binding to the native maize protein, is competitively inhibited by the safener dichlormid and the herbicides S-ethyl dipropylthiocarbamate, alachlor, and metolachlor. SBP1 is predicted to encode a phenolic O-methyltransferase, but SafBP does not O-methylate catechol or caffeic acid. The acquisition of its encoding gene opens experimental approaches for the evaluation of the role of SafBP in response to the relevant safeners and herbicides.

Plant Physiol. (1998) 116: 1083-1089
Copyright Clearance Center:   0032-0889/98/116/1083/07
© 1998 American Society of Plant Physiologists

This article has been cited by other articles:

				B. P. DeRidder and P. B. Goldsbrough Organ-Specific Expression of Glutathione S-Transferases and the Efficacy of Herbicide Safeners in Arabidopsis Plant Physiology, January 1, 2006; 140(1): 167 - 175. [Abstract] [Full Text] [PDF]

				M. Nakazono, F. Qiu, L. A. Borsuk, and P. S. Schnable Laser-Capture Microdissection, a Tool for the Global Analysis of Gene Expression in Specific Plant Cell Types: Identification of Genes Expressed Differentially in Epidermal Cells or Vascular Tissues of Maize PLANT CELL, March 1, 2003; 15(3): 583 - 596. [Abstract] [Full Text] [PDF]

				C. NDong, D. Anzellotti, R. K. Ibrahim, N. P. A. Huner, and F. Sarhan Daphnetin Methylation by a Novel O-Methyltransferase Is Associated with Cold Acclimation and Photosystem II Excitation Pressure in Rye J. Biol. Chem., February 21, 2003; 278(9): 6854 - 6861. [Abstract] [Full Text] [PDF]

				F. Xu, E. S. Lagudah, S. P. Moose, and D. E. Riechers Tandemly Duplicated Safener-Induced Glutathione S-Transferase Genes from Triticum tauschii Contribute to Genome- and Organ-Specific Expression in Hexaploid Wheat Plant Physiology, September 1, 2002; 130(1): 362 - 373. [Abstract] [Full Text] [PDF]