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ARTICLE

The Potassium Transporter AtKUP12 Enhances Tolerance to Salt Stress through the Maintenance of the K⁺/Na⁺ Ratio in Arabidopsis

Hua Zhang^#, Zhongmin Yang^#, Xilong You, Youqiang Heng, Yan Wang^*

Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, 830046, China

* Corresponding Author: Yan Wang. Email:
# These authors have contributed equally to this work

(This article belongs to the Special Issue: Plant Physiology for Crop Production and Sustainable Agriculture)

Phyton-International Journal of Experimental Botany 2021, 90(2), 389-402. https://doi.org/10.32604/phyton.2021.014156

Received 03 September 2020; Accepted 25 October 2020; Issue published 07 February 2021

Abstract

Potassium (K⁺) is a necessary nutrient for plant growth and crop production. The K⁺ transporter plays crucial roles in the absorption and transport of K⁺ in plants. Most K⁺ transporters in Arabidopsis have been reported, but AtKUP12, which is a member of the KT/KUP/HAK family, has not yet been the subject of relevant in-depth research. In the present study, we demonstrated that AtKUP12 plays a crucial role in K⁺ uptake in Arabidopsis under 100 μM lowK⁺ and 125 mM salt stress conditions. AtKUP12 transcripts were induced by K⁺ deficiency and salt stress. We analyzed the K⁺ uptake of AtKUP12 using the K⁺ uptake-deficient yeast R5421 and Arabidopsis mutant atkup12. Transformation with AtKUP12 rescued the growth defect of mutant yeast and atkup12 mutant plants at the low-K⁺ concentration, which suggested that AtKUP12 might be involved in high-affinity K⁺ uptake in low-K⁺ environments. In comparison to the wild-type (WT) and atkup12-AtKUP12 complementation lines, atkup12 showed a dramatic reduction in potassium concentration, K⁺/Na⁺ ratio, and root and shoot growth on 12-day-old seedlings under the salt conditions; however, there was no significant difference between the complementation and WT lines. Taken together, these results demonstrate that AtKUP12 might participate in salt tolerance in Arabidopsis through K⁺ uptake and K⁺/Na⁺ homeostasis.

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