Coordinated activation of as-1-type elements and a tobacco glutathione S-transferase gene by auxins, salicylic acid, methyl-jasmonate and hydrogen peroxide.
The molecular mechanism of signal transduction pathways which mediate the action of phytohormones are poorly understood. Recently, we and others have shown that the as -1 type cis-acting elements can respond to auxin and salicylic acid, two well-characterized signaling molecules in plants. In the present work, we have examined a comprehensive set of physiological and abiotic agents and found that auxin, salicylic acid and methyl-jasmonate are three effective inducers of the as-1-type elements in transgenic tobacco. Using a cell suspension culture containing a synthetic promoter-GUS fusion, we demonstrated rapid and sensitive induction of the as-1-type element by these phytohormones. Furthermore, a tobacco glutathione S-transferase gene, GNT35, that contains an as-1-type binding site in its promoter is also inducible by auxin, salicylic acid and methyl-jasmonate with similar kinetics. As Ulmasov et al. have recently reported, we found that the as-1-type elements can also respond to weak/inactive analogues of auxin and salicylic acid. In addition, we show that hydrogen peroxide can also effectively activate the expression of GNT35 as well as the as-1-type element in a cell suspension culture, but not with whole seedlings. These results are discussed with respect to the possible mechanism(s) through which a single cis element may respond to a diverse array of molecules.
Xiang
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C
AgBiotech Center, Rutgers University, New Brunswick, NJ 08903-0231, USA.
Miao
Z H
ZH
Lam
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D000085:Acetates / Q000494:pharmacology; D001665:Binding Sites; D003517:Cyclopentanes / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D017930:Genes, Reporter / Q000235:genetics; D005966:Glucuronidase / Q000235:genetics; D005982:Glutathione Transferase / Q000235:genetics; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000494:pharmacology; D054883:Oxylipins; D010937:Plant Growth Regulators / Q000494:pharmacology*; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D018749:RNA, Plant / Q000032:analysis; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D012459:Salicylates / Q000494:pharmacology; D020156:Salicylic Acid; D015398:Signal Transduction / Q000235:genetics*; D014026:Nicotiana / Q000235:genetics*
D000085:Acetates; D003517:Cyclopentanes; D007210:Indoleacetic Acids; D054883:Oxylipins; D010937:Plant Growth Regulators; D012333:RNA, Messenger; D018749:RNA, Plant; D012459:Salicylates; C072239:methyl jasmonate; D006861:Hydrogen Peroxide; D005982:Glutathione Transferase; D005966:Glucuronidase; D020156:Salicylic Acid