Physiology and Molecular Basis of Thallium Toxicity and Accumulation in Arabidopsis Thaliana
Journal
SSRN
ISSN
15565068
Date Issued
2022-08-22
Author(s)
Chang, Hsin-Fang
Tseng, Shao-Chin
Tang, Mau-Tsu
Hsiao, Silver Sung-Yun
Lee, Der-Chuen
Yeh, Kuo-Chen
Abstract
Thallium (Tl) is a non-essential metal mobilized through industrial processes that can lead to it entering the environment and exerting toxic effects. Plants are fundamental components of all ecosystems. Therefore, understanding the effects of Tl on plant growth and development is of great importance for assessing potential environmental risks of Tl. Here, the responses of Arabidopsis thaliana to Tl were elucidated using a battery of physiological, genetic, and transcriptome analyses. Thallium can be absorbed by roots and translocated to the aerial parts, accumulating at similar concentrations throughout plant parts. Genetic evidence supported regulation of Tl uptake and movement by different molecular compartments within plants. Thallium primarily caused growth inhibition, oxidative stress, leaf chlorosis, and the impairment of K homeostasis. The disturbance of redox balance toward oxidative stress was supported by significant expression differences of genes involved in oxidative stress and antioxidant defense under Tl exposure. Reduced GSH levels in cad2-1 mutant rendered plants highly sensitive to Tl, suggesting that GSH has a prominent role in alleviating Tl-triggered oxidative responses. Thallium down-regulating the expression of LCHII-related genes is believed to be responsible for leaf chlorosis. The findings illuminate some underlying mechanisms of Tl toxicity at physiological and molecular levels in plants.
Subjects
Arabidopsis thaliana
glutathione
photosynthesis
potassium homeostasis
thallium
Publisher
SSRN
Type
preprint