1. Ethylene insensitive mutation increases Arabidopsis tolerance to Cd in NPR1-dependent manner.
- Author
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Zhou, Yutong, Liu, Chuan, Li, Guangzhe, and Hao, Lin
- Subjects
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PECTINESTERASE , *ARABIDOPSIS , *ETHYLENE , *PROTEOLYSIS , *GENE expression - Abstract
Background and aims: Ethylene-insensitive mutation (ein)-conferred Arabidopsis tolerance to Cd has been reported. However, the mechanisms involved are far from clear. This study explores possible mechanisms. Methods: Arabidopsis wild-type (WT), and ein2–1, npr1–1 (nonexpressor of PR gene 1), and npr1–1/ein2–1 (abbreviated to n1e2) were exposed to 50 μM CdCl2 for 48 h or 7 d (just for assessment of plant growth). Some physiological and biochemical parameters, and gene expression were analyzed. Results: Exposure to Cd inhibited growth of aerial parts and roots. However, as compared with WT, an increased tolerance was observed in ein2–1, a similar pattern in npr1–1, whereas a more sensitive performance in n1e2. Higher antioxidative capacity and lower oxidative damage occurred in ein2–1 than in other tested genotypes under Cd stress. The expression of five selected pectin methylesterase inhibitor (PMEI)-encoding genes was all significantly up-regulated in ein2–1 compared to others under Cd stress, leading to the largest decrease of PME activity in this genotype. Under Cd stress, the activity of root cytoplasmic invertase was induced only in ein2–1, while cell wall- and vacuolar isoforms were suppressed, especially obviously in ein2–1 relative to other genotypes. Gene expression suggested that invertase activity could be regulated at transcriptional and posttranslational levels under Cd stress. Additionally, ubiquitin proteasome system-mediated protein degradation, Cd chelation and vacuolar sequestration might also participate in plant responses to Cd stress. Conclusions: This study provides evidence that ethylene insensitive mutation increases Arabidopsis plant tolerance to Cd in NPR1-dependent manner. This may involve many biological processes, among which the inhibitory effect of PMEIs on PME activity was especially striking. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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