Author

Yimin Li

Year of Award

2016

Degree Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Biology.

Principal Supervisor

Xia, Yiji

Keywords

Arabidopsis;Effect of stress on;Molecular aspects;Oxidative stress;Plants

Language

English

Abstract

Cellular redox states mediate various physiological and developmental processes. Mechanisms involved in sensing cellular redox state and linking it to an appropriate physiological response remains poorly understood in plants. Arabidopsis bZIP68 was previously found to undergo reversible oxidation in its Cys320 in cells under oxidative stress. In this study, it was found that bZIP68 was localized in the nucleus in Arabidopsis seedlings under normal conditions. Upon treatment of oxidative stress, bZIP68 underwent nucleocytoplasmic shuttling and accumulated in the cytoplasm. This stress-dependent nucleocytoplasmic shuttling depends on the redox-sensitive Cys320 and its nuclear export signal. bZIP68 suppresses expression of stress response genes under normal conditions and its loss-of-function mutation of bZIP68 leads to elevated expression of genes involved in oxidative stress defense including genes encoding for antioxidant proteins and for enzymes involved in biosynthesis of small molecule antioxidants. The bzip68 mutant also showed enhanced responses to stress treatment such as the oxidative stress and cold stress. Our study suggests that bZIP68 directly or indirectly senses perturbation of cellular redox states and links the redox change to activation of oxidative stress defense genes through redox regulation of transcription.

Comments

Principal supervisor: Prof. Xia Yiji.;Thesis submitted to the Department of Biology.;Thesis (Ph.D.)--Hong Kong Baptist University, 2016.;

Bibliography

Includes bibliographical references (pages 88-108)

Available for download on Tuesday, February 27, 2018



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