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Shao Y, Li S, Gao L, Sun C, Hu J, Ullah A, Gao J, Li X, Liu S, Jiang D, Cao W, Tian Z, Dai T. Magnesium Application Promotes Rubisco Activation and Contributes to High-Temperature Stress Alleviation in Wheat During the Grain Filling. FRONTIERS IN PLANT SCIENCE 2021; 12:675582. [PMID: 34177993 PMCID: PMC8231710 DOI: 10.3389/fpls.2021.675582] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 04/21/2021] [Indexed: 06/01/2023]
Abstract
Inhibited photosynthesis caused by post-anthesis high-temperature stress (HTS) leads to decreased wheat grain yield. Magnesium (Mg) plays critical roles in photosynthesis; however, its function under HTS during wheat grain filling remains poorly understood. Therefore, in this study, we investigated the effects of Mg on the impact of HTS on photosynthesis during wheat grain filling by conducting pot experiments in controlled-climate chambers. Plants were subjected to a day/night temperature cycle of 32°C/22°C for 5 days during post-anthesis; the control temperature was set at 26°C/16°C. Mg was applied at the booting stage, with untreated plants used as a control. HTS reduced the yield and net photosynthetic rate (P n ) of wheat plants. The maximum carboxylation rate (V Cmax ), which is limited by Rubisco activity, decreased earlier than the light-saturated potential electron transport rate. This decrease in V Cmax was caused by decreased Rubisco activation state under HTS. Mg application reduced yield loss by stabilizing P n . Rubisco activation was enhanced by increasing Rubisco activase activity following Mg application, thereby stabilizing P n . We conclude that Mg maintains Rubisco activation, thereby helping to stabilize P n under HTS.
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Affiliation(s)
- Yuhang Shao
- Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Shiyu Li
- Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Lijun Gao
- Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Chuanjiao Sun
- Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Jinling Hu
- Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Attiq Ullah
- Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Jingwen Gao
- Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Xinxin Li
- Rural Energy and Environment Agency, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Sixi Liu
- Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
- Chengdu Agricultural Technology Extension Station, Chengdu, China
| | - Dong Jiang
- Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Weixing Cao
- Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Zhongwei Tian
- Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Tingbo Dai
- Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
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Gulati U, Rajesh UC, Rawat DS, Zaleski JM. Development of Magnesium Oxide-Silver Hybrid Nanocatalysts for Synergistic Carbon Dioxide Activation to Afford Esters and Heterocycles at Ambient Pressure. GREEN CHEMISTRY : AN INTERNATIONAL JOURNAL AND GREEN CHEMISTRY RESOURCE : GC 2020; 22:3170-3177. [PMID: 33795971 PMCID: PMC8009290 DOI: 10.1039/c9gc04040d] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Multi-metallic hybrid nancatalysts consisting of a porous metal oxide host and metal satellite guests serve as a scaffold for multi-step transformations of divergent and energy-challenging substrates. Here we have developed a 3D porous MgO framework (Lewis basic host) with Ag0 nanoparticles (noble metal guest) for ambient pressure activation and insertion of CO2 into unsaturated alkyne substrates. The hybrid MgO@Ag-x (x = 2, 5, 7, 8 at % Ag) catalysts are synthesized by impregnating Ag+ ions in porous MgO cubes followed by reduction using NaBH4. Morphological (SEM, TEM, EDX mapping) and structural (PXRD, XPS) characterization reveal that the micron-sized hybrid cubes derive from self-assembly of ~100 nm (edge length) MgO cubes decorated with ~ 5 to 25 nm Ag0 NPs. Detailed XPS analysis illustrates Ag0 is present in two forms, <10 nm NPs and ~25 nm aggregates. The MgO@Ag-7 catalyst is effective for inserting CO2 into aryl alkynes followed by SN2 coupling with allylic chlorides to afford a wide range of ester and lactone heterocycles in excellent yields (61-93%) and with low E-factor (2.8). The proposed mechanism suggests a CO2 capture and substrate assembly role for 3D porous MgO while Ag0 performs the key activation of alkyne and CO2 insertion steps. The catalyst is recyclable (5x) with no significant loss of product yield. Overall, these results demonstrate viable approaches to hybrid catalyst development for challenging conversions such as CO2 utilization in a green and sustainable manner.
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Affiliation(s)
- Upasana Gulati
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
- Department of Chemistry, University of Delhi, Delhi-110007, India
| | - U Chinna Rajesh
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Diwan S Rawat
- Department of Chemistry, University of Delhi, Delhi-110007, India
| | - Jeffrey M Zaleski
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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Enrichment and Identification of the Most Abundant Zinc Binding Proteins in Developing Barley Grains by Zinc-IMAC Capture and Nano LC-MS/MS. Proteomes 2018; 6:proteomes6010003. [PMID: 29342075 PMCID: PMC5874762 DOI: 10.3390/proteomes6010003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/07/2018] [Accepted: 01/11/2018] [Indexed: 01/02/2023] Open
Abstract
Background: Zinc accumulates in the embryo, aleurone, and subaleurone layers at different amounts in cereal grains. Our hypothesis is that zinc could be stored bound, not only to low MW metabolites/proteins, but also to high MW proteins as well. Methods: In order to identify the most abundant zinc binding proteins in different grain tissues, we microdissected barley grains into (1) seed coats; (2) aleurone/subaleurone; (3) embryo; and (4) endosperm. Initial screening for putative zinc binding proteins from the different tissue types was performed by fractionating proteins according to solubility (Osborne fractionation), and resolving those via Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) followed by polyvinylidene fluoride (PVDF) membrane blotting and dithizone staining. Selected protein fractions were subjected to Zn2+-immobilized metal ion affinity chromatography, and the captured proteins were identified using nanoscale liquid chromatography coupled to tandem mass spectrometry (nanoLC-MS/MS). Results: In the endosperm, the most abundant zinc binding proteins were the storage protein B-hordeins, gamma-, and D-hordeins, while in the embryo, 7S globulins storage proteins exhibited zinc binding. In the aleurone/subaleurone, zinc affinity captured proteins were late abundant embryogenesis proteins, dehydrins, many isoforms of non-specific lipid transfer proteins, and alpha amylase trypsin inhibitor. Conclusions: We have shown evidence that abundant barley grain proteins have been captured by Zn-IMAC, and their zinc binding properties in relationship to the possibility of zinc storage is discussed.
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Yang C, Zhang Z, Gao H, Liu M, Fan X. Mechanisms by which the infection of Sclerotinia sclerotiorum (Lib.) de Bary affects the photosynthetic performance in tobacco leaves. BMC PLANT BIOLOGY 2014; 14:240. [PMID: 25246003 PMCID: PMC4180539 DOI: 10.1186/s12870-014-0240-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Accepted: 09/04/2014] [Indexed: 05/21/2023]
Abstract
BACKGROUND Sclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic fungal pathogen which causes disease in a wide range of plants. An observed decrease in photosynthetic performance is the primary reason for the reduction of crop yield induced by S. sclerotiorum. The H2C2O4 is the main pathogenic material secreted by S. sclerotiorum, but the effects of H2C2O4 acidity and the C2O4 2- ion on photosynthetic performance remain unknown. RESULTS S. sclerotiorum infection significantly decreased photosynthetic O2 evolution and the maximum quantum yield of photosystem II (Fv/Fm) in tobacco leaves under high-light. H2C2O4 (the main pathogenic material secreted by S. sclerotiorum) with pH 4.0 also significantly decreased photosynthetic performance. However, treatment with H3PO4 and HCl at the same pH as H2C2O4 caused much less decrease in photosynthetic performance than H2C2O4 did. These results verify that the acidity of the H2C2O4 secreted by S. sclerotiorum was only partially responsible for the observed decreases in photosynthesis. Treatment with 40 mM K2C2O4 decreased Fv/Fm by about 70% of the levels observed under 40 mM H2C2O4, which further demonstrates that C2O4(2-) was the primary factor that impaired photosynthetic performance during S. sclerotiorum infection. K2C2O4 treatment did not further decrease photosynthetic performance when D1 protein synthesis was fully inhibited, indicating that C2O4(2-) inhibited PSII by repressing D1 protein synthesis. It was observed that K2C2O4 treatment inhibited the rate of RuBP regeneration and carboxylation efficiency. In the presence of a carbon assimilation inhibitor, K2C2O4 2 treatment did not further decrease photosynthetic performance, which infers that C2O4(2-) inhibited PSII activity partly by repressing the carbon assimilation. In addition, it was showed that C2O4(2-) treatment inhibited the PSII activity but not the PSI activity. CONCLUSIONS This study demonstrated that the damage to the photosynthetic apparatus induced by S. sclerotiorum is not only caused by the acidity of H2C2O4, but also by C2O4(2-) which plays a much more important role in damaging the photosynthetic apparatus. C2O4(2-) inhibits PSII activity, as well as the rate of RuBP regeneration and carboxylation efficiency, leading to the over production of reactive oxygen species (ROS). By inhibiting the synthesis of D1, ROS may further accelerate PSII photoinhibition.
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Affiliation(s)
- Cheng Yang
- />State Key Lab of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, Shandong 271018 China
- />Wheat Research Center, Henan Academy of Agricultural Sciences, Zhengzhou, Henan 450002 China
| | - Zishan Zhang
- />State Key Lab of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, Shandong 271018 China
| | - Huiyuan Gao
- />State Key Lab of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, Shandong 271018 China
| | - Meijun Liu
- />State Key Lab of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, Shandong 271018 China
| | - Xingli Fan
- />State Key Lab of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, Shandong 271018 China
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Tcherkez G. Modelling the reaction mechanism of ribulose-1,5-bisphosphate carboxylase/oxygenase and consequences for kinetic parameters. PLANT, CELL & ENVIRONMENT 2013; 36:1586-96. [PMID: 23305122 DOI: 10.1111/pce.12066] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 12/12/2012] [Accepted: 12/26/2012] [Indexed: 05/20/2023]
Abstract
Although ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) was discovered nearly 60 years ago, the associated chemical mechanism of the reaction is still incompletely understood. The catalytic cycle consists of four major steps: ribulose-1,5-bisphosphate binding, enolization, CO₂ or O₂ addition and hydration, and cleavage of the intermediate. The use of individual rate constants for these elemental steps yields mathematical expressions for usual kinetic constants (k(cat), K(m)), CO₂ versus O₂ specificity (S(c/o)) as well as other chemical parameters such as the ¹²C/¹³C isotope effect. That said, most of them are not simple and thus the interpretation of experimental and observed values of kcat , Km and Sc/o may be more complicated than expected. That is, Rubisco effective catalysis depends on several kinetic parameters that are influenced by both the biological origin and the cellular medium (which, in turn, can vary with environmental conditions). In this brief review, we present the basic model of Rubisco kinetics and describe how subtle biochemical changes (which may have occurred along Evolution) can easily modify Rubisco catalysis.
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Affiliation(s)
- Guillaume Tcherkez
- Institut de Biologie des Plantes, CNRS UMR 8618, Université Paris-Sud, 91405 Orsay Cedex, France.
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