The Soybean GH2/4 Gene That Encodes a Glutathione S-Transferase Has a Promoter That Is Activated by a Wide Range of Chemical Agents

Abstract

Transcriptional activation of the soybean (Glycine max) C H Z / 4 gene (also referred to as GmhspZ6-A) and increase in abundance of the C H Z / 4 mRNA (also referred to as pCE54) have been previously shown to occur following treatment of soybean seedlings with auxins, nonauxin analogs, heavy metals, and a variety of other agents. To determine whether the G H Z / 4 promoter is responsive to an array of different agents, we have analyzed the inducibility of the C H Z / 4 promoter fused to the p-glucuronidase reporter gene in transgenic tobacco (Nicotiana tabacum) plants. We have shown that a wide variety of chemical agents induce this promoter in a tissue-specific and concentration-dependent manner. In addition, we have used an affinity-purified antibody raised against recombinant G H Z / 4 protein to show that the G H Z / 4 protein increases in response to auxin application and is localized in the cytosol of soybean cells. Recombinant G H Z / 4 protein can be purified to homogeneity on a glutathione-agarose resin, and the purified protein has glutathione Stransferase activity when assayed with the substrate 1 -chloro-2,4-dinitrobenzene.

Literature review: Phytoaccumulation of chromium, uranium, and plutonium in plant systems

“…This enzyme, located in the cytosol (Ulmasov et al 1995), performs the last genetically defined step in anthocyanin biosynthesis, namely tagging an anthocyanin precursor, cyandin-3-glycoside with glutathione, allowing for recognition and targeting of anthocyanins into the vacuole via and Mg/ATP-dependent, ABC-type GSH pump located in the tonoplast (Marrs, et al, 1996). This mechanism has been confirmed by the use of vanadate, which inhibits transport into the vacuole by inhibiting the tonoplast GSH pump (Marrs et al 1996).…”

“…Therefore, these genes appear to encode multifunctional stress proteins which may be critical in heavy metal detoxification. Studies with the promoter sequence of GmGSTZ6-A fused to the reporter gene, uidA, show that the promoter is induced by Cd and a variety of other chemical agents including hydrogen peroxide (Ulmasov et al, 1995). Ulmasov et al (1995) theorized that GSTs are synthesized in response to an oxidative stress, i.e., a general stress that is the result of a variety of agents such as heavy metals that cause the production of active oxygen species.…”

“…In maize (Marrs et al 1996), the bronze 2 gene (Bz2) encodes for the enzyme, glutathione S-transferase (GST) as does the soybean counterpart gene GmGST26-A (Ulmasov et al 1995).…”

A Genomics Approach to the Comprehensive Analysis of the Glutathione S-Transferase Gene Family in Soybean and Maize

“…1). We found four soybean type I GSTs, one soybean type II GST, and 20 type III GSTs including the four previously described in the literature (Ulmasov et al, 1995;Andrews et al, 1997;McGonigle and O'Keefe, 1998;Skipsey et al, 2000) for a total of 25 GSTs in soybean (Table II; Fig. 2).…”

“…In soybean, GH2/4 (also known as Gmhsp26-A) was cloned independently as a heat shock protein (Czarnecka et al, 1988) and an auxin-induced protein (Hagen et al, 1984). Only later was the protein identified as a GST: first on the basis of homology to other cloned GSTs and later by showing that the protein is able to conjugate GSH to the model substrate 1-chloro-2,4-dinitrobenzene (CDNB; Ulmasov et al, 1995). Besides heat shock and auxin, a wide range of chemical agents including abscisic acid, kinetin, gibberellic acid, polyethylene glycol, canavine, KCl, NaF, and heavy metals induce GH2/4 message levels.…”