Identification of an immediate-early salicylic acid-inducible tobacco gene and characterization of induction by other compounds.
Tobacco genes that are induced in response to salicylic acid (SA) treatment with immediate-early kinetics were identified by differential mRNA display. Detailed analysis of IS10a, one cDNA clone identified by this method, revealed induction within 30 min of treatment, with a peak of expression at 3 h, that decayed rapidly thereafter. Treatment with the protein synthesis inhibitor, cycloheximide (CHX), also caused induction of IS10a mRNA to comparable levels, but the IS10a mRNA continued to accumulate after 3 h of induction. In combination, CHX and SA led to a superinduction of IS10a mRNA levels that was also sustained. Half-maximal induction was evident at ca. 100-150 microM SA. In addition to SA, induction of IS10a occurred to varying degrees upon treatment with acetylsalicylic acid, benzoic acid, 2,4-dichlorophenoxyacetic acid, methyl jasmonate, and hydrogen peroxide, whereas treatment with other compounds had no effect. The proteins encoded by IS10a and a second highly homologous cDNA show sequence similarity to UDP-glucose: flavonoid glucosyltransferases.
Horvath
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Laboratory of Plant Molecular Biology, Rockefeller University, New York, NY 10021, USA.
Chua
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NH
D000595:Amino Acid Sequence; D003513:Cycloheximide / Q000494:pharmacology; D018076:DNA, Complementary / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017781:Genes, Immediate-Early; D017343:Genes, Plant; D007700:Kinetics; D008969:Molecular Sequence Data; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010947:Plants, Toxic; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D018749:RNA, Plant / Q000032:analysis; D012459:Salicylates / Q000494:pharmacology*; D020156:Salicylic Acid; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014026:Nicotiana / Q000187:drug effects / Q000235:genetics*
D018076:DNA, Complementary; D010937:Plant Growth Regulators; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D018749:RNA, Plant; D012459:Salicylates; D003513:Cycloheximide; D020156:Salicylic Acid