Expression Patterns of Glutathione Transferase Gene (GstI) in Maize Seedlings Under Juglone-Induced Oxidative Stress

Hubert Sytykiewicz

doi:10.3390/ijms12117982

Abstract

Juglone (5-hydroxy-1,4-naphthoquinone) has been identified in organs of many plant species within Juglandaceae family. This secondary metabolite is considered as a highly bioactive substance that functions as direct oxidant stimulating the production of reactive oxygen species (ROS) in acceptor plants. Glutathione transferases (GSTs, E.C.2.5.1.18) represent an important group of cytoprotective enzymes participating in detoxification of xenobiotics and limiting oxidative damages of cellular macromolecules. The purpose of this study was to investigate the impact of tested allelochemical on growth and development of maize (Zea mays L.) seedlings. Furthermore, the effect of juglone-induced oxidative stress on glutathione transferase (GstI) gene expression patterns in maize seedlings was recorded. It was revealed that 4-day juglone treatment significantly stimulated the transcriptional activity of GstI in maize seedlings compared to control plants. By contrast, at the 6th and 8th day of experiments the expression gene responses were slightly lower as compared with non-stressed seedlings. Additionally, the specific gene expression profiles, as well as the inhibition of primary roots and coleoptile elongation were proportional to juglone concentrations. In conclusion, the results provide strong molecular evidence that allelopathic influence of juglone on growth and development of maize seedlings may be relevant with an induction of oxidative stress in acceptor plants.

Highlights

Juglone (5-hydroxy-1,4-naphthoquinone) is an allelochemical that has been isolated from tissues and organs of many plant species belonging to Juglandaceae family [1,2,3]
Juglone naturally occurs mainly as a non-toxic glycosylated form, but when exposed to the air or soil components, this allelochempound is immediately transformed into the oxidized and highly toxic form [4,5]. Allelopathic potential of this walnut constituent leads to inhibition of seed germination and growth of susceptible acceptor plants [6,7,8,9,10]. Detrimental impact of this naphthoquinone may be associated with suppressing the intensity of a wide range of physiological processes and biochemical reactions occurring in plant tissues [9,11,12]
It has been found that germination process of maize seeds was significantly suppressed under juglone-induced oxidative stress (Figure 1)

Summary

Introduction

Juglone (5-hydroxy-1,4-naphthoquinone) is an allelochemical that has been isolated from tissues and organs of many plant species belonging to Juglandaceae family [1,2,3]. Juglone naturally occurs mainly as a non-toxic glycosylated form (hydrojuglone β-D-glucopyranoside), but when exposed to the air or soil components, this allelochempound is immediately transformed into the oxidized and highly toxic form [4,5]. Allelopathic potential of this walnut constituent leads to inhibition of seed germination and growth of susceptible acceptor plants [6,7,8,9,10]. That the cytotoxic effects of this allelochemical are restricted towards plants and include a large spectrum of antiviral, antibacterial, antifungal and nematicidal activities [3,19,20,21]

Objectives

Results

Conclusion