Plant Glutathione S-Transferases, a Tale of Theta and Tau

Abstract

Glutathione S-transferases (GSTs, EC 2.5.1.18) are ubiquitous enzymes that catalyze the addition of glutathione to a wide variety of substrates. Plant GSTs have been studied mainly in relation to their role in the detoxification of herbicides, mostly in maize. Recently, several gst genes have been isolated as genes that respond to the plant hormone auxin with increased transcription. Pathogen infections and other treatments have also been found to lead to increased expression of gst genes. It is now apparent that different types of plant gst genes and activities exist in most plant species, but their functional relationships and their relationships to the action of auxin are still poorly understood. Here, a historic overview on plant GSTs will be presented. Based on primary sequence differences, a new class of plant GSTs, tau, will be proposed. The possible roles of auxin and oxidative stress in inducing gst genes will be discussed. Hopefully this review will help develop new ideas and stimulate new research to study the functions of the ever growing family of plant GSTs.

Site-directed Mutagenesis of the Evolutionarily Conserved Tyr8 Residue in Rice Phi-class Glutathione S-transferase F3

“…[4][5][6] Individual GST isozymes can selectively detoxify specific xenobiotics with species differences in GST specificity and capacity determining herbicide selectivity. 5,7,8 In plants, studies regarding GSTs have mainly focused on their ability to detoxify herbicides.…”

Cloning and characterization of a tau glutathione S-transferase subunit encoding gene in Gossypium hirsutum

“…In general, the molecular mass of each subunit was in the range of 25-27 kDa in GSTs (Edwards et al, 2000). The expression of GSTs could be induced by herbicides, hormones, pathogen, environmental toxins, therapeutic drugs and products of oxidative stresses (Droog, 1997). Consequently, the GSTs could protect tissues against oxidative damages, reduce the organic hydroperoxides and transport amphiphatic compounds and plant hormones as carrier proteins (Marrs, 1996;Listowski et al, 1988).…”

“…Subsequently, the nomenclature of animal GSTs was proposed to be extended and used in plant. And three classes of GSTs were set up, namely theta, tau and zeta (Droog, 1997). This classification system was amended following the full genome of Arabidopsis sequenced.…”

A szalicilsav előkezelés hatása a sóstressz akklimatizációra különös tekintettel a glutation transzferázok szerepére paradicsom és lúdfű növényekben

“…A GST-k az élővilágban széleskörűen elterjedt enzimek, megtalálhatóak a baktériumokban, gombákban, rovarokban, emlősökben és a magasabb rendű növényekben egyaránt (Droog 1997). A növényi GST-k diverz, számos funkcióval rendelkező enzimcsoportot alkotnak, amelyek katalitikus reakcióik során szubsztrátként GSH-t (γ-Glu-Cys-Gly) használnak.…”

“…A GST-k szerepét a sejtre káros vegyületek detoxifikálásában és a szövetek oxidatív károsodás elleni védelmében, valamint a másodlagos anyagcseretermékek, pl. a flavonoid származékok, metabolizmusában és biokémiai reakcióiban már több évtizede leírták (Marrs 1996, Droog 1997 A GST-ket leginkább a genetikai modellnövényként jól ismert lúdfűben jellemezték.…”