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Hydrogen peroxide functions as a secondary messenger for brassinosteroids-induced CO2 assimilation and carbohydrate metabolism in Cucumis sativus
- Source :
- Journal of Zhejiang University. Science. B. 13(10)
- Publication Year :
- 2012
-
Abstract
- Brassinosteroids (BRs) are potent regulators of photosynthesis and crop yield in agricultural crops; however, the mechanism by which BRs increase photosynthesis is not fully understood. Here, we show that foliar application of 24-epibrassinolide (EBR) resulted in increases in CO(2) assimilation, hydrogen peroxide (H(2)O(2)) accumulation, and leaf area in cucumber. H(2)O(2) treatment induced increases in CO(2) assimilation whilst inhibition of the H(2)O(2) accumulation by its generation inhibitor or scavenger completely abolished EBR-induced CO(2) assimilation. Increases of light harvesting due to larger leaf areas in EBR- and H(2)O(2)-treated plants were accompanied by increases in the photochemical efficiency of photosystem II (Φ(PSII)) and photochemical quenching coefficient (q(P)). EBR and H(2)O(2) both activated carboxylation efficiency of ribulose-1,5-bisphosphate oxygenase/carboxylase (Rubisco) from analysis of CO(2) response curve and in vitro measurement of Rubisco activities. Moreover, EBR and H(2)O(2) increased contents of total soluble sugar, sucrose, hexose, and starch, followed by enhanced activities of sugar metabolism such as sucrose phosphate synthase, sucrose synthase, and invertase. Interestingly, expression of transcripts of enzymes involved in starch and sugar utilization were inhibited by EBR and H(2)O(2). However, the effects of EBR on carbohydrate metabolisms were reversed by the H(2)O(2) generation inhibitor diphenyleneodonium (DPI) or scavenger dimethylthiourea (DMTU) pretreatment. All of these results indicate that H(2)O(2) functions as a secondary messenger for EBR-induced CO(2) assimilation and carbohydrate metabolism in cucumber plants. Our study confirms that H(2)O(2) mediates the regulation of photosynthesis by BRs and suggests that EBR and H(2)O(2) regulate Calvin cycle and sugar metabolism via redox signaling and thus increase the photosynthetic potential and yield of crops.
- Subjects :
- inorganic chemicals
Chlorophyll
Sucrose
Ribulose-Bisphosphate Carboxylase
Carbohydrate metabolism
Photosynthesis
Second Messenger Systems
General Biochemistry, Genetics and Molecular Biology
Gene Expression Regulation, Enzymologic
chemistry.chemical_compound
Steroids, Heterocyclic
Plant Growth Regulators
Gene Expression Regulation, Plant
Brassinosteroids
General Pharmacology, Toxicology and Pharmaceutics
General Veterinary
biology
RuBisCO
fungi
food and beverages
General Medicine
Hydrogen Peroxide
Carbohydrate
Carbon Dioxide
Biomedicine & Biotechnology
Invertase
chemistry
Biochemistry
Seedlings
biology.protein
Sucrose synthase
Carbohydrate Metabolism
Sucrose-phosphate synthase
Cucumis sativus
Reactive Oxygen Species
Subjects
Details
- ISSN :
- 18621783
- Volume :
- 13
- Issue :
- 10
- Database :
- OpenAIRE
- Journal :
- Journal of Zhejiang University. Science. B
- Accession number :
- edsair.doi.dedup.....d5c91d1abd2987c1806d5c2da5629d88