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

• Published in: Stress biology Vol. 2; no. 1; p. 46
• Main Authors: Li, Yanhui, Hu, Jin, Qi, Jie, Zhao, Fameng, Liu, Jiahao, Chen, Linlin, Chen, Lu, Gu, Jiangjiang, Wu, Honghong, Li, Zhaohu
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 08-11-2022; Springer Nature B.V; Springer
• Subjects: Abiotic stress; Agricultural production; Agriculture; Animal Physiology; Biomedical and Life Sciences; Chlorophyll; Chloroplasts; Gene expression; Homeostasis; K+/Na+ ratio; Life Sciences; Microbiology; Nanomaterials; Nanoparticles; Original Paper; Plant Sciences; Potassium transport and plant adaptation to hostile environments; Reactive oxygen species; Retention; Salinity; TEM imaging; TEM imaging; Reactive oxygen species; Na; Nanomaterials; K; Gene expression; ratio
• ISSN: 2731-0450; 2731-0450
• DOI: 10.1007/s44154-022-00065-y

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 (CeO
2
nanoparticles)] and PMO (polyacrylic acid coated Mn
3
O
4
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.