ISSN 10214437, Russian Journal of Plant Physiology, 2010, Vol. 57, No. 1, pp. 131–136. © Pleiades Publishing, Ltd., 2010.
Published in Russian in Fiziologiya Rastenii, 2010, Vol. 57, No. 1, pp. 139–145.
]GluCysGly) is a multifunc
tional tripeptide found in plants and animals. It is the
main nonprotein, lowmolecular thiol in most organ
isms [1, 2]. Glutathione participates in a variety of detox
ification, transport, and metabolic processes [3–5]. It is
a donor of reducing equivalents in the glutathione–
ascorbate shuttle (Halliwell–Asada cycle) . In this
process, a reduced form of glutathione becomes oxi
dized in order to reduce dehydroascorbate (which is
transformed into ascorbate). Restoration from the oxi
dized form of glutathione back to its reduced form is cat
alyzed by glutathione reductase (GR, EC. 220.127.116.11). Glu
tathione participates also in direct peroxide detoxifi
cation. In this reaction, reduced glutathione (GSH)
reacts with hydrogen peroxide (or another organic
peroxide) to yield water (or water and alcohol) and
glutathione dimer (GSSG). The process is accom
This text was submitted by the authors in English.
plished by glutathione peroxidase (EC 18.104.22.168) or
glutathione Stransferase (GST, EC. 22.214.171.124).
Important function of glutathione is its ability to
maintain sulfhydryl groups of intracellular proteins in
the correct oxidation states . The TG/GSSG ratio
is essential for the cell homeostasis and provides infor
mation regarding the capability of plants to withstand
the oxidative stress . Some authors suggest that the
glutathione redox state can be a valuable stress marker
in plant ecophysiological studies .
Glutathione is responsible for detoxification of
potentially harmful molecules, such as pesticides or
heavy metals . The process of conjugation can be
accomplished spontaneously or in the presence of
GST. The important role of GST for detoxification of
many herbicides is well known [5, 7]; furthermore,
some authors suggest that GST may play a significant
role in the process of phytoremediation . Glu
tathione also participates in the metabolism of various
compounds, including the aromatic organic mole
cules responsible for plant color, flavor, and fragrance,
storage form of reduced sulfur, etc. [2, 3, 7].
Glyphosate is a nonselective, postemergence her
bicide, widely used to eliminate unwanted plants both
in agricultural and nonagricultural landscapes . It is
Alterations in Glutathione Pool and Some Related Enzymes in Leaves
and Roots of Pea Plants Treated with the Herbicide Glyphosate
L. PE. Miteva
, S. V. Ivanov
, and V. S. Alexieva
Resbiomed EOOD, 4A Simeonovsko Shouse Blvd. Sofia, Bulgaria;
fax: +35929522407; email: email@example.com
Centre of Food Biology, 1592 Sofia, Bulgaria
Acad. M. Popov Institute of Plant Physiology, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
Received July 29, 2008
—Our previous studies have demonstrated that application of glyphosate caused oxidative events in
young pea and wheat plants. In this work, the changes in the endogenous level of glutathione (total and oxi
dized) and the activities of glutathione reductase (GR) and glutathione Stransferase (GST) after treatment
with glyphosate were studied in pea plants (
L., cv. Skinado). Glyphosate was applied in two
ways: (1) by leaf spraying with 10 mM solution; and (2) in nutrient medium as 0.01 mM solution. Measure
ments were made in both leaves and roots. Root and leaf treatments provoked the increase in both total and
oxidized glutathione contents. Both types of herbicide application caused activation of GR in treated organs.
Slight increase was detected also in untreated roots. It was found that glyphosate application to leaves pro
voked strong enhancement in the GST activity in leaves, while its root application stimulated the enzyme
activity in the roots. We observed the higher GST activity in the organ directly treated with herbicide. Fur
thermore, we suggested that the activated isoforms of GST(s) participated in detoxification of hydrogen per
oxide and lipid peroxides.
Key words: Pisum sativum glutathione glutathione reductase glutathione Stransferase glyphosate oxida
: CDNB—1chloro2,4dinitrobenzene; DTNB—
(2nitrobenzoic acid); GR—glutathione reduc
tase; GSH—reduced glutathione; GSSG—oxidized glutathione;
GST—glutathione Stransferase; PVP—polyvinylpyrrolidone;
SOD—superoxide dismutase; TG—total glutathione.