Improvement of leaf K+ retention is a shared mechanism behind CeO2 and Mn3O4 nanoparticles improved rapeseed salt tolerance

Yanhui Li; Jin Hu; Jie Qi; Fameng Zhao; Jiahao Liu; Linlin Chen; Lu Chen; Jiangjiang Gu; Honghong Wu; Zhaohu Li

doi:10.1007/s44154-022-00065-y

Improvement of leaf K⁺ retention is a shared mechanism behind CeO₂ and Mn₃O₄ nanoparticles improved rapeseed salt tolerance

Stress Biol. 2022 Nov 8;2(1):46. doi: 10.1007/s44154-022-00065-y.

Authors

Yanhui Li^#^{1

2}, Jin Hu^#^{1

2}, Jie Qi^{1

2}, Fameng Zhao^{1

2}, Jiahao Liu^{1

2}, Linlin Chen^{1

2}, Lu Chen³, Jiangjiang Gu³, Honghong Wu^{4

5}, Zhaohu Li^{1

2

6}

Affiliations

¹ MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan, 430070, China.
² Hubei Hongshan Laboratory, Wuhan, 430070, China.
³ College of Science, Huazhong Agricultural University, Wuhan, 430070, China.
⁴ MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan, 430070, China. honghong.wu@mail.hzau.edu.cn.
⁵ Hubei Hongshan Laboratory, Wuhan, 430070, China. honghong.wu@mail.hzau.edu.cn.
⁶ College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100083, China.

^# Contributed equally.

Abstract

Salinity is a global issue limiting efficient agricultural production. Nanobiotechnology has been emerged as an effective approach to improve plant salt tolerance. However, little known is about the shared mechanisms between different nanomaterials-enabled plant salt tolerance. In this study, we found that both PNC [polyacrylic acid coated nanoceria (CeO₂ nanoparticles)] and PMO (polyacrylic acid coated Mn₃O₄ nanoparticles) nanozymes improved rapeseed salt tolerance. PNC and PMO treated rapeseed plants showed significantly fresh weight, dry weight, higher chlorophyll content, Fv/Fm, and carbon assimilation rate than control plants under salt stress. Results from confocal imaging with reactive oxygen species (ROS) fluorescent dye and histochemical staining experiments showed that the ROS over-accumulation level in PNC and PMO treated rapeseed was significantly lower than control plants under salt stress. Confocal imaging results with K⁺ fluorescent dye showed that significantly higher cytosolic and vacuolar K⁺ signals were observed in PNC and PMO treated rapeseed than control plants under salt stress. This is further confirmed by leaf K⁺ content data. Furthermore, we found that PNC and PMO treated rapeseed showed significantly lower cytosolic Na⁺ signals than control plants under salt stress. While, compared with significantly higher vacuolar Na⁺ signals in PNC treated plants, PMO treated rapeseed showed significantly lower vacuolar Na⁺ signals than control plants under salt stress. These results are further supported by qPCR results of genes of Na⁺ and K⁺ transport. Overall, our results suggest that besides maintaining ROS homeostasis, improvement of leaf K⁺ retention could be a shared mechanism in nano-improved plant salt tolerance.

Keywords: Gene expression; K+/Na+ ratio; Nanomaterials; Reactive oxygen species; TEM imaging.

Abstract

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