Related Experiment Video
Updated: Dec 5, 2025
Real-Time Detection of Reactive Oxygen Species Production in Immune Response in Rice with a Chemiluminescence Assay
Published on: November 25, 2022
Manganese-induced oxidative stress, ultrastructural changes, and proteomics studies in rice plants
Ritika Rajpoot1, Rajneesh Kumar Srivastava1, Anjana Rani1
1Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
Abstract:
Manganese (Mn) is an essential element for plant growth but it becomes phytotoxic at higher concentrations. The effect of Mn-excess in hydroponics medium was examined on growth, oxidative stress, and ultrastructural changes in chloroplasts and mitochondria as well proteomic alterations in rice (Oryza sativa L.) seedlings. Seedlings grown with 1 mM and 2 mM Mn in nutrient medium for 8 days showed decline in length and fresh biomass, and decline in net photosynthetic rate, transpiration rate, and stomatal conductance. Shoots of the seedlings had higher Mn content than roots. Mn-treated seedlings showed increased production of O2·-, H2O2, and .OH, increased lipid peroxidation, increased carbonylation of proteins, and increased proteolytic activity compared to untreated seedlings. Mn-treated seedlings showed disorganization and swelling of chloroplasts with appearance of plastoglobuli in TEM images and deformity in shape of mitochondria. Using confocal microscopy depolarization of mitochondrial membrane was observed marked by green fluorescence of JC-1 dye monomers in Mn-treated roots. Proteomics studies from leaves of Mn-treated seedlings involving 2DE and PDQuest analysis showed differential expression of 23 proteins, among which MALDI-TOF/TOF mass spectrometry analysis revealed Mn-led downregulation of photosynthesis-related proteins, namely oxygen-evolving complex protein associated with PSII, PAP-3, enzyme involved in protein folding peptidyl-prolyl cis-trans isomerase (PPIase) and carbohydrate metabolizing enzymes hydrolase, fructose-bisphosphate aldolase, transketolase, and isocitrate dehydrogenase, whereas ATP-dependent Clp protease, peroxidase, and nucleic acid-binding proteins were downregulated due to Mn treatment. Results indicate that Mn-excess inhibits growth of rice plants with induction of oxidative stress, causing structural alterations in chloroplasts, mitochondria, inhibiting photosynthesis, and downregulating many photosynthesis and carbohydrate metabolism-related proteins.
Insights
Excess manganese (Mn) harms rice plant growth by inducing oxidative stress and damaging cellular structures. This study reveals Mn-excess inhibits photosynthesis and alters protein expression in rice seedlings.
Area of Science:
- Plant Physiology
- Biochemistry
- Molecular Biology
Background:
- Manganese (Mn) is vital for plant development but toxic at high levels.
- Understanding Mn phytotoxicity mechanisms is crucial for crop management.
Purpose of the Study:
- To investigate the effects of excess Mn on rice (Oryza sativa L.) seedling growth, oxidative stress, and cellular/proteomic changes.
- To identify key proteins affected by Mn toxicity in rice.
Main Methods:
- Rice seedlings were treated with 1 mM and 2 mM Mn in hydroponics.
- Evaluated growth parameters, photosynthetic rates, and oxidative stress markers (O₂⁻, H₂O₂, .OH, lipid peroxidation, protein carbonylation).
- Analyzed ultrastructural changes in chloroplasts and mitochondria using TEM and confocal microscopy.
- Utilized 2DE, PDQuest, and MALDI-TOF/TOF mass spectrometry for proteomic analysis.
Main Results:
- Mn excess reduced seedling length, biomass, net photosynthetic rate, transpiration, and stomatal conductance.
- Increased oxidative stress markers, lipid peroxidation, protein carbonylation, and proteolytic activity were observed.
- Ultrastructural damage included chloroplast disorganization, swelling, plastoglobuli, and mitochondrial deformity.
- Proteomics revealed downregulation of photosynthesis and carbohydrate metabolism proteins, and upregulation of stress-related proteins.
Conclusions:
- Mn excess severely inhibits rice growth and photosynthesis through oxidative stress and cellular damage.
- Specific protein alterations, particularly in photosynthesis and carbohydrate metabolism, are key indicators of Mn toxicity.
- Findings provide insights into the molecular mechanisms of Mn phytotoxicity in rice.
More Related Videos
08:09Development of a Cabbage Protoplast System for Studying Hypoxia Tolerance in Brassica
Published on: September 20, 2024
05:22Transverse Sectioning of Mature Rice Oryza sativa L. Kernels for Scanning Electron Microscopy Imaging Using Pipette Tips as Immobilization Support
Published on: January 25, 2022
