Wild Relatives of Wheat Respond Well to Water Deficit Stress: A Comparative Study of Antioxidant Enzyme Activities and Their Encoding Gene Expression

Alireza Pour-Aboughadareh,Mansoor Omidi,Alireza Etminan,Mohammad Reza Naghavi,Ali Ashraf Mehrabi,Peter Poczai

doi:10.3390/agriculture10090415

Abstract

Previous studies have revealed that some wild wheat accessions respond well to water deficit treatments and have a good potential in terms of photosynthetic parameters, root system architecture, and several physiological properties. However, the biochemical responses and molecular mechanisms of antioxidant-encoding genes remain to be elucidated. Herein, we investigated the most tolerant accessions from A. crassa, Ae. tauschii, and Ae. cylindrica previously identified from a core collection in previous studies, along with a control variety of bread wheat (T. aestivum cv. Sirvan) through measuring the shoot fresh and dry biomasses; the activities of antioxidant enzymes (including ascorbate peroxidase (APX), catalase (CAT), guaiacol peroxidase (GPX), and peroxidase (POD)); and the relative expression of CAT, superoxide dismutase (MnSOD), and GPX and APX genes under control and water deficit conditions. Water deficit stress caused a significant decrease in the shoot biomasses but resulted in an increase in the activity of all antioxidant enzymes and relative expression of antioxidant enzyme-encoding genes. Principal component analysis showed a strong association between the shoot dry biomass and the activity of CAT, POD, and APX, as well as MnSOD gene expression. Thus, these traits can be used as biomarkers to screen the tolerant plant material in the early growth stage. Taken together, our findings exposed the fact that Ae. tauschii and Ae. crassa respond better to water deficit stress than Ae. cylindrica and a control variety. Furthermore, these accessions can be subjected to further molecular investigation.

Highlights

Limitation in water availability for plants is the main challenge in agriculture, and their ability to cope with drought stress effects is of special economic importance
Significant differences were observed between the water treatments and accessions in terms of the shoot fresh and dry biomasses, with significant differences among accessions based on the analysis of variance (ANOVA)
The water deficit stress decreased the means of the shoot fresh biomass (SFB) and shoot dry biomass (SDB) by 38.65% and 58.06%, respectively, relative to the controls (Table 2)

Summary

Introduction

Limitation in water availability for plants is the main challenge in agriculture, and their ability to cope with drought stress effects is of special economic importance. The ROS family has different members, including singlet oxygen (1 O2 ), superoxide (O2− ), hydrogen peroxide (H2 O2 ), and hydroxyl radical (OH). These ROS immediately accumulate in different cell organelles, such as peroxisomes, chloroplasts, and mitochondria [5]. Plants have several protective mechanisms which enable them to detoxify additional ROS One of these mechanisms is the enzymatic group, which includes monodehydroascorbate reductase (MDHAR), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), the peroxidation detoxification product malondialdehyde (MDA), and glutathione reductase (GR). The regulation of the antioxidant enzyme-encoding gene expression could enhance plant tolerance to water-deficient conditions. The overexpression of genes encoding antioxidant enzymes may promote tolerance and oxidative stress induced by water deficit stress

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Discussion

Conclusion