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Liu WC, Han TT, Yuan HM, Yu ZD, Zhang LY, Zhang BL, Zhai S, Zheng SQ, Lu YT. CATALASE2 functions for seedling postgerminative growth by scavenging H 2 O 2 and stimulating ACX2/3 activity in Arabidopsis. Plant Cell Environ 2017; 40:2720-2728. [PMID: 28722222 DOI: 10.1111/pce.13031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 07/10/2017] [Accepted: 07/10/2017] [Indexed: 05/24/2023]
Abstract
Increased fatty acid β-oxidation is essential for early postgerminative growth in seedlings, but high levels of H2 O2 produced by β-oxidation can induce oxidative stress. Whether and how catalase (CAT) functions in fine-tuning H2 O2 homeostasis during seedling growth remain unclear. Here, we report that CAT2 functions in early seedling growth. Compared to the wild type, the cat2-1 mutant, with elevated H2 O2 levels, exhibited reduced root elongation on sucrose (Suc)-free medium, mimicking soils without exogenous sugar supply. Treatment with the H2 O2 scavenger potassium iodide rescued the mutant phenotype of cat2-1. In contrast to the wild type, the cat2-1 mutant was insensitive to the CAT inhibitor 3-amino-1,2,4-triazole in terms of root elongation when grown on Suc-free medium, suggesting that CAT2 modulates early seedling growth by altering H2 O2 accumulation. Furthermore, like cat2-1, the acyl-CoA oxidase (ACX) double mutant acx2-1 acx3-6 showed repressed root elongation, suggesting that CAT2 functions in early seedling growth by regulating ACX activity, as this activity was inhibited in cat2-1. Indeed, decreased ACX activity and short root of cat2-1 seedlings grown on Suc-free medium were rescued by overexpressing ACX3. Together, these findings suggest that CAT2 functions in early seedling growth by scavenging H2 O2 and stimulating ACX2/3 activity.
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Affiliation(s)
- Wen-Cheng Liu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Tong-Tong Han
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Hong-Mei Yuan
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University, Haikou, 570228, China
| | - Zhen-Dong Yu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Lin-Yu Zhang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Bing-Lei Zhang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Shuang Zhai
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Si-Qiu Zheng
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Ying-Tang Lu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
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Yuan HM, Liu WC, Lu YT. CATALASE2 Coordinates SA-Mediated Repression of Both Auxin Accumulation and JA Biosynthesis in Plant Defenses. Cell Host Microbe 2017; 21:143-155. [PMID: 28182949 DOI: 10.1016/j.chom.2017.01.007] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/12/2016] [Accepted: 01/03/2017] [Indexed: 12/12/2022]
Abstract
Plants defend against pathogen attack by modulating auxin signaling and activating the salicylic acid (SA) and jasmonic acid (JA) signaling pathways. SA and JA act antagonistically in resistance to specific pathogen types, yet how plants coordinate these phytohormones remains elusive. Here we report that biotrophic-pathogen-induced SA accumulation dampens both auxin and JA synthesis by inhibiting CATALASE2 (CAT2) activity in the model plant Arabidopsis. SA suppression of CAT2 results in increased H2O2 levels and subsequent sulfenylation of tryptophan synthetase β subunit 1, thus depleting the auxin biosynthetic precursor tryptophan. In addition, we find that CAT2 promotes JA biosynthesis by facilitating direct interaction of the JA biosynthetic enzymes ACX2 and ACX3, and thus SA repression of CAT2 inhibits JA accumulation. As such, the cat2-1 mutant exhibits increased resistance to biotrophic pathogens and increased susceptibility to necrotrophic pathogens. Our study illustrates how CAT2 coordinates SA repression of auxin accumulation and JA biosynthesis in plant defense.
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Affiliation(s)
- Hong-Mei Yuan
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Wen-Cheng Liu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Ying-Tang Lu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China.
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