The effect of glyceollin on soybean (Glycine max L.) tonoplast and plasma membrane vesicles

John L. Giannini, Jana S. Holt, Donald P. Briskin

Research output: Contribution to journalArticle

Abstract

An improved method for the isolation of transport-competent plasma membrane and tonoplast vesicles from soybean (Glycine max L., Co. Harsoy) is presented. When resolved on linear sucrose gradients, the soybean membrane vesicles displayed two peaks of ATP-dependent H+-transport activity that were inhibited by either vanadate (plasma membrane) or nitrate (tonoplast). That the vanadate and nitrate sensitive H+-transport activities were representative of plasma membrane and tonoplast vesicles was further supported by their differing pH optima for ATP-dependent H+-transport. Membrane vesicles displaying vanadate sensitive H+ transport showed optimal activity at pH 6.5 while membrane vesicles displaying nitrate sensitive H+-transport showed optimal activity at pH 7.5. When ATP-dependent H+-transport was examined as a function of Mg:ATP concentration, both vesicle types displayed simple Michaelis-Menten type kinetics and Km-values of 0.56 and 0.97 mM were observed for plasma membrane and tonoplast vesicles, respectively. Incubation of plasma membrane or tonoplast vesicles with glyceollin resulted in an inhibition of ATP-dependent H+-transport. While ninety percent inhibition of ATP-dependent H+-transport was observed with tonoplast vesicles when incubated with 25 μM glyceollin, a 4-fold higher concentration of the phytoalexin was required to produce a similar inhibition with plasma membrane vesicles. Although glyceollin had only small effects upon ATP hydrolytic activity, this compound increased the H+-conductance of the vesicles in a manner consistent with the relative inhibition of ATP-dependent H+-transport.

Original languageEnglish (US)
Pages (from-to)203-211
Number of pages9
JournalPlant Science
Volume74
Issue number2
DOIs
StatePublished - 1991

Keywords

  • glyceollin
  • proton conductance
  • soybean

ASJC Scopus subject areas

  • Genetics
  • Agronomy and Crop Science
  • Plant Science

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