Journal Article

Herbicide safener-binding protein of maize: purification, cloning, and expression of an encoding cDNA

Scott-Craig, J.S, Poduje, L, Walton, J.D, Casida, J.E

1998

Overview

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-oxazolidine ([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.

• Publisher: American Society of Plant Physiologists
• Subject: alachlor / amides / Amino Acid Sequence / amino acid sequences / Amino acids / Arabidopsis / Arabidopsis thaliana / Avena sativa / Base Sequence / binding proteins / Biological and medical sciences / biosynthesis / Carrier Proteins / Carrier Proteins - biosynthesis / Carrier Proteins - genetics / Carrier Proteins - isolation & purification / Chemical control / chloroacetanilide herbicides / cloning / Cloning, Molecular / Coleoptiles / Complementary DNA / Corn / dichlormid / dichloroacetic acid / DNA, Complementary / DNA, Complementary - isolation & purification / drug effects / enzyme activity / Escherichia coli / Escherichia coli - genetics / etiolation / Fundamental and applied biological sciences. Psychology / Gels / genbank/af033496 / gene expression / genes / genetic code / genetic regulation / genetics / herbicide safeners / Herbicides / Herbicides - metabolism / Herbicides - toxicity / Hordeum vulgare / isoelectric point / isolation & purification / leaves / metabolism / metolachlor / Molecular Sequence Data / molecular weight / Nicotiana tabacum / Oxazoles / Oxazoles - metabolism / Parasitic plants. Weeds / phenolic-o-methyltransferase / physicochemical properties / Phytopathology. Animal pests. Plant and forest protection / Plant Proteins / Plant Proteins - biosynthesis / Plant Proteins - genetics / Plant Proteins - isolation & purification / Plants / Protein Binding / Protein Binding - genetics / protein composition / purification / sbp1 genes / Seedlings / Sequence Analysis, DNA / Sorghum / Sorghum bicolor / thiocarbamate herbicides / Thiocarbamates / toxicity / transferases / Triticum aestivum / Weeds / Whole Plant, Environmental, and Stress Physiology / Zea mays / Zea mays - drug effects / Zea mays - genetics / Zea mays - metabolism