Changes in biosynthesis and metabolism of glutathione upon ochratoxin A stress in Arabidopsis thaliana

• Published in: Plant physiology and biochemistry 2014-06, Vol.79, p.10-18
• Main Authors: Wang, Yan, Zhao, Weiwei, Hao, Junran, Xu, Wentao, Luo, YunBo, Wu, Weihong, Yang, Zhuojun, Liang, Zhihong, Huang, Kunlun
• Format: Article
• Language: English
• Subjects: Arabidopsis - drug effects; Arabidopsis - enzymology; Arabidopsis - metabolism; Arabidopsis thaliana; Biological and medical sciences; Buthionine Sulfoximine; Fundamental and applied biological sciences. Psychology; Glutamate–cysteine ligase; Glutathione; Glutathione - metabolism; Glutathione Disulfide - metabolism; Glutathione peroxidase; Glutathione reductase; Glutathione-S-transferase; Ochratoxin A; Ochratoxins - pharmacology; Oxidation-Reduction - drug effects; Oxidative Stress - drug effects; Plant physiology and development
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2014.03.001

Ochratoxin A (OTA) is one of the most toxic mycotoxins, which is toxic to plants and simulates oxidative stress. Glutathione is an important antioxidant in plants and is closely associated with detoxification in cells. We have previously shown that OTA exposure induces obvious expression differences in genes associated with glutathione metabolism. To characterize glutathione metabolism and understand its role in OTA phytotoxicity, we observed the accumulation of GSH in the detached leaves of Arabidopsis thaliana under OTA treatment. OTA stimulated a defense response through enhancing glutathione-S-transferase, glutathione peroxidase, glutathione reductase activities, and the transcript levels of these enzymes were increased to maintain the total glutathione content. Moreover, the level of oxidized glutathione (GSSG) was increased and the ascorbate–glutathione cycle fluctuated in response to OTA. The depletion of glutathione using buthionine sulfoximine (BSO, inhibitor of glutamate–cysteine ligase) had no profound effect on OTA toxicity, as glutathione was regenerated through the ascorbate–glutathione cycle to maintain the total glutathione content. The ROS, MDA and GSH accumulation was significantly affected in the mutant gsh1, gr1 and gpx2 after treatment with OTA, which indicated that glutathione metabolism is directly involved in the oxidative stress response of Arabidopsis thaliana subjected to OTA. In conclusion, date demonstrate that glutathione-associated metabolism is closely related with OTA stress and glutathione play a role in resistance of Arabidopsis subjected to OTA. •OTA stimulated to enhance the activity and the transcript levels of GST, GPX and GR.•The GSSG level increased and ascorbate–glutathione cycle fluctuated induced by OTA.•The depletion of glutathione using BSO had no profound effect on OTA toxicity.•The ROS, MDA and GSH was affected in mutant of gsh1, gr1 and gpx2 after OTA stimulus.