1
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Alonzo EA, Lato TJ, Gonzalez M, Olson TL, Savage QR, Garza LN, Green MT, Koone JC, Cook NE, Dashnaw CM, Armstrong DB, Wood JL, Garbrecht LS, Haynes ML, Jacobson MR, Guberman-Pfeffer MJ, Minkara MS, Wedler HB, Zechmann B, Shaw BF. Universal pictures: A lithophane codex helps teenagers with blindness visualize nanoscopic systems. Sci Adv 2024; 10:eadj8099. [PMID: 38198555 PMCID: PMC10780880 DOI: 10.1126/sciadv.adj8099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 12/14/2023] [Indexed: 01/12/2024]
Abstract
People with blindness have limited access to the high-resolution graphical data and imagery of science. Here, a lithophane codex is reported. Its pages display tactile and optical readouts for universal visualization of data by persons with or without eyesight. Prototype codices illustrated microscopy of butterfly chitin-from N-acetylglucosamine monomer to fibril, scale, and whole insect-and were given to high schoolers from the Texas School for the Blind and Visually Impaired. Lithophane graphics of Fischer-Spier esterification reactions and electron micrographs of biological cells were also 3D-printed, along with x-ray structures of proteins (as millimeter-scale 3D models). Students with blindness could visualize (describe, recall, distinguish) these systems-for the first time-at the same resolution as sighted peers (average accuracy = 88%). Tactile visualization occurred alongside laboratory training, synthesis, and mentoring by chemists with blindness, resulting in increased student interest and sense of belonging in science.
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Affiliation(s)
- Emily A. Alonzo
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Travis J. Lato
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Mayte Gonzalez
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Trevor L. Olson
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Quentin R. Savage
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Levi N. Garza
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Morgan T. Green
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Jordan C. Koone
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Noah E. Cook
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Chad M. Dashnaw
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | | | - John L. Wood
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Lisa S. Garbrecht
- Texas Advanced Computing Center, The University of Texas at Austin, Austin, TX, USA
| | - Madeline L. Haynes
- Texas Advanced Computing Center, The University of Texas at Austin, Austin, TX, USA
| | - Miriam R. Jacobson
- Texas Advanced Computing Center, The University of Texas at Austin, Austin, TX, USA
| | | | - Mona S. Minkara
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | | | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, TX, USA
| | - Bryan F. Shaw
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
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2
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Király L, Zechmann B, Albert R, Bacsó R, Schwarczinger I, Kolozsváriné Nagy J, Gullner G, Hafez YM, Künstler A. Enhanced Resistance to Viruses in Nicotiana edwardsonii 'Columbia' Is Dependent on Salicylic Acid, Correlates with High Glutathione Levels, and Extends to Plant-Pathogenic Bacteria and Abiotic Stress. Mol Plant Microbe Interact 2024; 37:36-50. [PMID: 37750816 DOI: 10.1094/mpmi-07-23-0106-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 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] [Indexed: 09/27/2023]
Abstract
Our earlier research showed that an interspecific tobacco hybrid (Nicotiana edwardsonii 'Columbia' [NEC]) displays elevated levels of salicylic acid (SA) and enhanced resistance to localized necrotic symptoms (hypersensitive response [HR]) caused by tobacco mosaic virus (TMV) and tobacco necrosis virus (TNV), as compared with another interspecific hybrid (Nicotiana edwardsonii [NE]) derived from the same parents. In the present study, we investigated whether symptomatic resistance in NEC is indeed associated with the inhibition of TMV and TNV and whether SA plays a role in this process. We demonstrated that enhanced viral resistance in NEC is manifested as both milder local necrotic (HR) symptoms and reduced levels of TMV and TNV. The presence of an adequate amount of SA contributes to the enhanced defense response of NEC to TMV and TNV, as the absence of SA resulted in seriously impaired viral resistance. Elevated levels of subcellular tripeptide glutathione (GSH) in NEC plants in response to viral infection suggest that in addition to SA, GSH may also contribute to the elevated viral resistance of NEC. Furthermore, we found that NEC displays an enhanced resistance not only to viral pathogens but also to bacterial infections and abiotic oxidative stress induced by paraquat treatments. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Lóránt Király
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, One Bear Place, no. 97046, Waco, TX 76798, U.S.A
| | - Réka Albert
- Institute of Plant Sciences and Environmental Protection, Faculty of Agriculture, University of Szeged, H-6800, Hódmezővásárhely, Hungary
| | - Renáta Bacsó
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Ildikó Schwarczinger
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Judit Kolozsváriné Nagy
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Gábor Gullner
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Yaser Mohamed Hafez
- EPCRS Excellence Center & Plant Pathology and Biotechnology Lab, Department of Agricultural Botany, Faculty of Agriculture, Kafrelsheikh University, 33516 Kafr-El-Sheikh, Egypt
| | - András Künstler
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
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3
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Sheikh A, Zechmann B, Sayes CM, Taube JH, Greathouse KL. A preparation of bacterial outer membrane with osmium tetroxide and uranyl acetate co-stain enables improved structural determination by transmission electron microscopy. Microscopy (Oxf) 2023; 72:515-519. [PMID: 37148329 PMCID: PMC10673695 DOI: 10.1093/jmicro/dfad027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 04/10/2023] [Accepted: 05/04/2023] [Indexed: 05/08/2023] Open
Abstract
Biological nanoparticles, such as bacterial outer membrane vesicles (OMVs), are routinely characterized through transmission electron microscopy (TEM). In this study, we report a novel method to prepare OMVs for TEM imaging. To preserve vesicular shape and structure, we developed a dual fixation protocol involving osmium tetroxide incubation prior to negative staining with uranyl acetate. Combining osmium tetroxide with uranyl acetate resulted in preservation of sub-50 nm vesicles and improved morphological stability, enhancing characterization of lipid-based nanoparticles by TEM.
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Affiliation(s)
- Aadil Sheikh
- Department of Biology, Baylor University, One Bear Place #97046, Waco, TX 76798, USA
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, One Bear Place #97046, Waco, TX 76798, USA
| | - Christie M Sayes
- Department of Environmental Science, Baylor University, One Bear Place #97046, Waco, TX 76798, USA
| | - Joseph H Taube
- Department of Biology, Baylor University, One Bear Place #97046, Waco, TX 76798, USA
| | - K. Leigh Greathouse
- Department of Biology, Baylor University, One Bear Place #97046, Waco, TX 76798, USA
- Nutrition Sciences, Baylor University, One Bear Place #97311, Waco, TX 76798, USA
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4
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Vojta L, Rac-Justament A, Zechmann B, Fulgosi H. Thylakoid Rhodanese-like Protein-Ferredoxin:NADP + Oxidoreductase Interaction Is Integrated into Plant Redox Homeostasis System. Antioxidants (Basel) 2023; 12:1838. [PMID: 37891917 PMCID: PMC10604066 DOI: 10.3390/antiox12101838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 09/27/2023] [Accepted: 10/05/2023] [Indexed: 10/29/2023] Open
Abstract
In vascular plants, the final photosynthetic electron transfer from ferredoxin (Fd) to NADP+ is catalyzed by the flavoenzyme ferredoxin:NADP+ oxidoreductase (FNR). FNR is recruited to thylakoid membranes via an integral membrane protein TROL (thylakoid rhodanese-like protein) and the membrane associated protein Tic62. We have previously demonstrated that the absence of TROL triggers a very efficient superoxide (O2•-) removal mechanism. The dynamic TROL-FNR interaction has been shown to be an apparently overlooked mechanism that maintains linear electron flow before alternative pathway(s) is(are) activated. In this work, we aimed to further test our hypothesis that the FNR-TROL pair could be the source element that triggers various downstream networks of chloroplast ROS scavenging. Tandem affinity purification followed by the MS analysis confirmed the TROL-FNR interaction and revealed possible interaction of TROL with the thylakoid form of the enzyme ascorbate peroxidase (tAPX), which catalyzes the H2O2-dependent oxidation of ascorbate and is, therefore, the crucial component of the redox homeostasis system in plants. Further, EPR analyses using superoxide spin trap DMPO showed that, in comparison with the wild type, plants overexpressing TROL (TROL OX) propagate more O2•- when exposed to high light stress. This indicates an increased sensitivity to oxidative stress in conditions when there is an excess of membrane-bound FNR and less free FNR is found in the stroma. Finally, immunohistochemical analyses of glutathione in different Arabidopsis leaf cell compartments showed highly elevated glutathione levels in TROL OX, indicating an increased demand for this ROS scavenger in these plants, likely needed to prevent the damage of important cellular components caused by reactive oxygen species.
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Affiliation(s)
- Lea Vojta
- Laboratory for Molecular Plant Biology and Biotechnology, Division of Molecular Biology, Institute Ruđer Bošković, Bijenička cesta 54, HR-10000 Zagreb, Croatia
| | - Anja Rac-Justament
- Laboratory for Molecular Plant Biology and Biotechnology, Division of Molecular Biology, Institute Ruđer Bošković, Bijenička cesta 54, HR-10000 Zagreb, Croatia
| | - Bernd Zechmann
- Center for Microscopy and Imaging (CMI), Baylor University, One Bear Place #97046, Waco, TX 76798-7046, USA
| | - Hrvoje Fulgosi
- Laboratory for Molecular Plant Biology and Biotechnology, Division of Molecular Biology, Institute Ruđer Bošković, Bijenička cesta 54, HR-10000 Zagreb, Croatia
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5
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Feng X, Yu Z, Fang H, Jiang H, Yang G, Chen L, Zhou X, Hu B, Qin C, Hu G, Xing G, Zhao B, Shi Y, Guo J, Liu F, Han B, Zechmann B, He Y, Liu F. Plantorganelle Hunter is an effective deep-learning-based method for plant organelle phenotyping in electron microscopy. Nat Plants 2023; 9:1760-1775. [PMID: 37749240 DOI: 10.1038/s41477-023-01527-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 08/25/2023] [Indexed: 09/27/2023]
Abstract
Accurate delineation of plant cell organelles from electron microscope images is essential for understanding subcellular behaviour and function. Here we develop a deep-learning pipeline, called the organelle segmentation network (OrgSegNet), for pixel-wise segmentation to identify chloroplasts, mitochondria, nuclei and vacuoles. OrgSegNet was evaluated on a large manually annotated dataset collected from 19 plant species and achieved state-of-the-art segmentation performance. We defined three digital traits (shape complexity, electron density and cross-sectional area) to track the quantitative features of individual organelles in 2D images and released an open-source web tool called Plantorganelle Hunter for quantitatively profiling subcellular morphology. In addition, the automatic segmentation method was successfully applied to a serial-sectioning scanning microscope technique to create a 3D cell model that offers unique views of the morphology and distribution of these organelles. The functionalities of Plantorganelle Hunter can be easily operated, which will increase efficiency and productivity for the plant science community, and enhance understanding of subcellular biology.
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Affiliation(s)
- Xuping Feng
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
- College of Life Sciences, Nanjing Agricultural University, Nanjing, China
- The Rural Development Academy & Agricultural Experiment Station, Zhejiang University, Huzhou, China
| | - Zeyu Yu
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
- The Rural Development Academy & Agricultural Experiment Station, Zhejiang University, Huzhou, China
| | - Hui Fang
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
- Huzhou Institute of Zhejiang University, Hangzhou, China
| | - Hangjin Jiang
- Center for Data Science, Zhejiang University, Hangzhou, China
| | - Guofeng Yang
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
- The Rural Development Academy & Agricultural Experiment Station, Zhejiang University, Huzhou, China
| | - Liting Chen
- College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Xinran Zhou
- College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Bing Hu
- College of Life Sciences, Nanjing Agricultural University, Nanjing, China
- Biological Experiment Teaching Center, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Chun Qin
- College of Life Sciences, Nanjing Agricultural University, Nanjing, China
- Biological Experiment Teaching Center, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Gang Hu
- College of Life Sciences, Nanjing Agricultural University, Nanjing, China
- Biological Experiment Teaching Center, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Guipei Xing
- College of Life Sciences, Nanjing Agricultural University, Nanjing, China
- Biological Experiment Teaching Center, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Boxi Zhao
- College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Yongqiang Shi
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Jiansheng Guo
- Center of Cryo-Electron Microscopy, Zhejiang University School of Medicine, Hangzhou, China
| | - Feng Liu
- School of Mathematics and Statistics, University of Melbourne, Parkville, Australia
| | - Bo Han
- Department of Computer Science, Hong Kong Baptist University, Hong Kong, China
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, TX, USA
| | - Yong He
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China.
| | - Feng Liu
- College of Life Sciences, Nanjing Agricultural University, Nanjing, China.
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6
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Zechmann B. Different Imaging Techniques for the 2 and 3D Characterization of Plant Cell Ultrastructure in the SEM and TEM. Microsc Microanal 2023; 29:874-875. [PMID: 37613715 DOI: 10.1093/micmic/ozad067.432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, Texas, United States
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7
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Vojvodić S, Dimitrijević M, Žižić M, Dučić T, Aquilanti G, Stanić M, Zechmann B, Danilović Luković J, Stanković D, Opačić M, Morina A, Pittman JK, Spasojević I. A three-step process of manganese acquisition and storage in the microalga Chlorella sorokiniana. J Exp Bot 2023; 74:1107-1122. [PMID: 36453904 DOI: 10.1093/jxb/erac472] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 07/25/2022] [Accepted: 11/25/2022] [Indexed: 06/17/2023]
Abstract
Metabolism of metals in microalgae and adaptation to metal excess are of significant environmental importance. We report a three-step mechanism that the green microalga Chlorella sorokiniana activates during the acquisition of and adaptation to manganese (Mn), which is both an essential trace metal and a pollutant of waters. In the early stage, Mn2+ was mainly bound to membrane phospholipids and phosphates in released mucilage. The outer cell wall was reorganized and lipids were accumulated, with a relative increase in lipid saturation. Intracellular redox settings were rapidly altered in the presence of Mn excess, with increased production of reactive oxygen species that resulted in lipid peroxidation and a decrease in the concentration of thiols. In the later stage, Mn2+ was chelated by polyphosphates and accumulated in the cells. The structure of the inner cell wall was modified and the redox milieu established a new balance. Polyphosphates serve as a transient Mn2+ storage ligand, as proposed previously. In the final stage, Mn was stored in multivalent Mn clusters that resemble the structure of the tetramanganese-calcium core of the oxygen-evolving complex. The present findings elucidate the bioinorganic chemistry and metabolism of Mn in microalgae, and may shed new light on water-splitting Mn clusters.
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Affiliation(s)
- Snežana Vojvodić
- University of Belgrade - Institute for Multidisciplinary Research, Life Sciences Department, Belgrade, Serbia
| | - Milena Dimitrijević
- University of Belgrade - Institute for Multidisciplinary Research, Life Sciences Department, Belgrade, Serbia
| | - Milan Žižić
- University of Belgrade - Institute for Multidisciplinary Research, Life Sciences Department, Belgrade, Serbia
| | | | | | - Marina Stanić
- University of Belgrade - Institute for Multidisciplinary Research, Life Sciences Department, Belgrade, Serbia
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, TX, USA
| | - Jelena Danilović Luković
- University of Belgrade - Institute for Multidisciplinary Research, Life Sciences Department, Belgrade, Serbia
- University of Belgrade, Institute for Application of Nuclear Energy, Belgrade, Serbia
| | | | - Miloš Opačić
- University of Belgrade - Institute for Multidisciplinary Research, Life Sciences Department, Belgrade, Serbia
| | - Arian Morina
- University of Belgrade - Institute for Multidisciplinary Research, Life Sciences Department, Belgrade, Serbia
- Faculty of Science and Natural Resources, University Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Jon K Pittman
- Department of Earth and Environmental Sciences, School of Natural Sciences, The University of Manchester, Manchester, UK
| | - Ivan Spasojević
- University of Belgrade - Institute for Multidisciplinary Research, Life Sciences Department, Belgrade, Serbia
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Wilburn D, Fletcher E, Ismaeel A, Miserlis D, Zechmann B, Koutakis P. Chemical and cryo-collection of muscle samples for transmission electron microscopy using Methacarn and dimethyl sulfoxide ✰. Ultramicroscopy 2022; 241:113600. [PMID: 35988477 PMCID: PMC9511158 DOI: 10.1016/j.ultramic.2022.113600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 07/08/2022] [Accepted: 08/10/2022] [Indexed: 01/24/2023]
Abstract
Muscle samples are commonly chemically fixed or frozen immediately upon collection for biochemical and morphological analysis. Certain fixatives such as glutaraldehyde and osmium tetroxide are widely used for transmission electron microscopy (TEM) and lead to adequate preservation of muscle ultrastructure, but do not preserve the molecular features of samples. Methacarn is suggested to be a preferable chemical fixative for light microscopy because it maintains immunohistological features of samples. However, the efficacy of methacarn to preserve ultrastructural features as a primary chemical fixative for TEM is currently unclear. Additionally, cryo-preservation of samples for TEM analysis involves freezing processes such as plunge freezing, slam freezing, or high pressure freezing. High pressure freezing is the considered the gold standard but requires costly equipment and may not be a viable option for many labs collecting tissue samples from remote locations. Dimethyl sulfoxide (DMSO) is a commonly used cryoprotectant that may allow for better structural preservation of samples by impairing ice damage that occurs during plunge/snap freezing. We aimed to assess the effectiveness of methacarn as a primary chemical fixative and determine the effect of pre-coating samples with DMSO before plunge/snap freezing tissues to be prepared for TEM. The micrographs of the methcarn-fixed samples indicate a loss of Z-disk integrity, intermyofibrillar space, mitochondria structure, and lipids. Ultimately, methacarn is not a viable primary fixative for tissue sample preparation for TEM. Similarly, liquid nitrogen freezing of samples wrapped in aluminum foil produced non-uniform Z-disk alignments that appeared smeared with swollen mitochondria. DMSO coating before freezing appears to lessen the alterations to contractile and mitochondrial morphological structures. DMSO appears to be useful for preserving the ultrastructure of sarcomeres if samples are covered before freezing.
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Affiliation(s)
- Dylan Wilburn
- Department of Health, Human Performance, and Recreation, Baylor University, 254-710-2911, B.207 Baylor Science Building, One Bear Place #97388, 76798-7388, Waco, TX 76706, USA
| | - Emma Fletcher
- Department of Biology, Baylor University, Waco, TX 76706, USA
| | - Ahmed Ismaeel
- Department of Biology, Baylor University, Waco, TX 76706, USA
| | - Dimitrios Miserlis
- Department of Surgery, University of Texas Health Science Center San Antonio, San Antonio, TX, USA
| | - Bernd Zechmann
- Department of Biology, Baylor University, Waco, TX 76706, USA; Center for Microscopy and Imaging, Baylor University, Waco, Texas 76706, USA
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9
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Redkar A, Sabale M, Schudoma C, Zechmann B, Gupta YK, López-Berges MS, Venturini G, Gimenez-Ibanez S, Turrà D, Solano R, Di Pietro A. Conserved secreted effectors contribute to endophytic growth and multihost plant compatibility in a vascular wilt fungus. Plant Cell 2022; 34:3214-3232. [PMID: 35689625 PMCID: PMC9421472 DOI: 10.1093/plcell/koac174] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 06/03/2022] [Indexed: 05/04/2023]
Abstract
Fungal interactions with plant roots, either beneficial or detrimental, have a crucial impact on agriculture and ecosystems. The cosmopolitan plant pathogen Fusarium oxysporum (Fo) provokes vascular wilts in more than a hundred different crops. Isolates of this fungus exhibit host-specific pathogenicity, which is conferred by lineage-specific Secreted In Xylem (SIX) effectors encoded on accessory genomic regions. However, such isolates also can colonize the roots of other plants asymptomatically as endophytes or even protect them against pathogenic strains. The molecular determinants of endophytic multihost compatibility are largely unknown. Here, we characterized a set of Fo candidate effectors from tomato (Solanum lycopersicum) root apoplastic fluid; these early root colonization (ERC) effectors are secreted during early biotrophic growth on main and alternative plant hosts. In contrast to SIX effectors, ERCs have homologs across the entire Fo species complex as well as in other plant-interacting fungi, suggesting a conserved role in fungus-plant associations. Targeted deletion of ERC genes in a pathogenic Fo isolate resulted in reduced virulence and rapid activation of plant immune responses, while ERC deletion in a nonpathogenic isolate led to impaired root colonization and biocontrol ability. Strikingly, some ERCs contribute to Fo infection on the nonvascular land plant Marchantia polymorpha, revealing an evolutionarily conserved mechanism for multihost colonization by root infecting fungi.
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Affiliation(s)
| | - Mugdha Sabale
- Departamento de Genética, Universidad de Córdoba, 14071 Córdoba, Spain
| | | | - Bernd Zechmann
- Baylor University, Center for Microscopy and Imaging, Waco, Texas 76798, USA
| | - Yogesh K Gupta
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK
| | | | | | - Selena Gimenez-Ibanez
- Plant Molecular Genetics Department, Centro Nacional de Biotecnologıa-CSIC (CNB-CSIC), 28049 Madrid, Spain
| | - David Turrà
- Department of Agriculture and Center for Studies on Bioinspired Agro-enviromental Technology, Università di Napoli Federico II, 80055 Portici, Italy
| | - Roberto Solano
- Plant Molecular Genetics Department, Centro Nacional de Biotecnologıa-CSIC (CNB-CSIC), 28049 Madrid, Spain
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10
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Koone JC, Dashnaw CM, Alonzo EA, Iglesias MA, Patero KS, Lopez JJ, Zhang AY, Zechmann B, Cook NE, Minkara MS, Supalo CA, Wedler HB, Guberman-Pfeffer MJ, Shaw BF. Data for all: Tactile graphics that light up with picture-perfect resolution. Sci Adv 2022; 8:eabq2640. [PMID: 35977019 PMCID: PMC9385137 DOI: 10.1126/sciadv.abq2640] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 06/17/2022] [Indexed: 06/15/2023]
Abstract
People who are blind do not have access to graphical data and imagery produced by science. This exclusion complicates learning and data sharing between sighted and blind persons. Because blind people use tactile senses to visualize data (and sighted people use eyesight), a single data format that can be easily visualized by both is needed. Here, we report that graphical data can be three-dimensionally printed into tactile graphics that glow with video-like resolution via the lithophane effect. Lithophane forms of gel electropherograms, micrographs, electronic and mass spectra, and textbook illustrations could be interpreted by touch or eyesight at ≥79% accuracy (n = 360). The lithophane data format enables universal visualization of data by people regardless of their level of eyesight.
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Affiliation(s)
- Jordan C. Koone
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Chad M. Dashnaw
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Emily A. Alonzo
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Miguel A. Iglesias
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Kelly-Shaye Patero
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Juan J. Lopez
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Ao Yun Zhang
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, TX, USA
| | - Noah E. Cook
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Mona S. Minkara
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | | | | | | | - Bryan F. Shaw
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
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Zechmann B, Möstl S, Zellnig G. Volumetric 3D reconstruction of plant leaf cells using SEM, ion milling, TEM, and serial sectioning. Planta 2022; 255:118. [PMID: 35522384 DOI: 10.1007/s00425-022-03905-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 02/25/2022] [Accepted: 04/26/2022] [Indexed: 06/14/2023]
Abstract
Focused ion beam scanning electron microscopy is well suited for volumetric extractions and 3D reconstructions of plant cells and its organelles. The three-dimensional (3D) reconstruction of individual plant cells is an important tool to extract volumetric data of organelles and is necessary to fully understand ultrastructural changes and adaptations of plants to their environment. Methods such as the 3D reconstruction of cells based on light microscopical images often lack the resolution necessary to clearly reconstruct all cell compartments within a cell. The 3D reconstruction of cells through serial sectioning transmission electron microscopy (ssTEM) and focused ion beam scanning electron microscopy (FIB-SEM) are powerful alternatives but not widely used in plant sciences. Here, we present a method for the 3D reconstruction and volumetric extraction of plant cells based on FIB milling and compare the results with 3D reconstructions obtained with ssTEM. When compared to 3D reconstruction based on ssTEM, FIB-SEM delivered similar results. The data extracted in this study demonstrated that tobacco cells were larger (31410 µm3) than pumpkin cells (20697 µm3) and contained more chloroplasts (175 vs. 124), mitochondria (1317 vs. 291) and peroxisomes (745 vs. 79). While individual chloroplasts, mitochondria, peroxisomes were larger in pumpkin plants (25, 53, and 50%, respectively) they covered more total volume in tobacco plants (5390, 395, 374 µm3, respectively) due to their higher number per cell when compared to pumpkin plants (4762, 134, 59 µm3, respectively). While image acquisition with FIB-SEM was automated, software controlled, and less difficult than ssTEM, FIB milling was slower and sections could not be revised or re-imaged as they were destroyed by the ion beam. Nevertheless, the results in this study demonstrated that both, FIB-SEM and ssTEM, are powerful tools for the 3D reconstruction of and volumetric extraction from plant cells and that there were large differences in size, number, and organelle composition between pumpkin and tobacco cells.
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Affiliation(s)
- Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, One Bear Place #97046, Waco, TX, 76798, USA.
| | - Stefan Möstl
- Institute of Biology, Plant Sciences, University of Graz, NAWI Graz, Schubertstrasse 51, 8010, Graz, Austria
| | - Günther Zellnig
- Institute of Biology, Plant Sciences, University of Graz, NAWI Graz, Schubertstrasse 51, 8010, Graz, Austria
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12
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Redkar A, Gimenez Ibanez S, Sabale M, Zechmann B, Solano R, Di Pietro A. Marchantia polymorpha model reveals conserved infection mechanisms in the vascular wilt fungal pathogen Fusarium oxysporum. New Phytol 2022; 234:227-241. [PMID: 34877655 DOI: 10.1111/nph.17909] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [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: 08/20/2021] [Accepted: 11/30/2021] [Indexed: 06/13/2023]
Abstract
Root-infecting vascular fungi cause wilt diseases and provoke devastating losses in hundreds of crops. It is currently unknown how these pathogens evolved and whether they can also infect nonvascular plants, which diverged from vascular plants over 450 million years ago. We established a pathosystem between the nonvascular plant Marchantia polymorpha (Mp) and the root-infecting vascular wilt fungus Fusarium oxysporum (Fo). On angiosperms, Fo exhibits exquisite adaptation to the plant xylem niche as well as host-specific pathogenicity, both of which are conferred by effectors encoded on lineage-specific chromosomes. Fo isolates displaying contrasting lifestyles on angiosperms - pathogenic vs endophytic - are able to infect Mp and cause tissue maceration and host cell killing. Using isogenic fungal mutants we define a set of conserved fungal pathogenicity factors, including mitogen activated protein kinases, transcriptional regulators and cell wall remodelling enzymes, that are required for infection of both vascular and nonvascular plants. Markedly, two host-specific effectors and a morphogenetic regulator, which contribute to vascular colonisation and virulence on tomato plants are dispensable on Mp. Collectively, these findings suggest that vascular wilt fungi employ conserved infection strategies on nonvascular and vascular plant lineages but also have specific mechanisms to access the vascular niche of angiosperms.
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Affiliation(s)
- Amey Redkar
- Departamento de Genética, Universidad de Córdoba, Córdoba, 14071, Spain
| | - Selena Gimenez Ibanez
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología CSIC, Campus Universidad Autónoma, Madrid, 28049, Spain
| | - Mugdha Sabale
- Departamento de Genética, Universidad de Córdoba, Córdoba, 14071, Spain
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, TX, 76798, USA
| | - Roberto Solano
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología CSIC, Campus Universidad Autónoma, Madrid, 28049, Spain
| | - Antonio Di Pietro
- Departamento de Genética, Universidad de Córdoba, Córdoba, 14071, Spain
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13
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Lujan H, Mulenos MR, Carrasco D, Zechmann B, Hussain SM, Sayes CM. Engineered aluminum nanoparticle induces mitochondrial deformation and is predicated on cell phenotype. Nanotoxicology 2022; 15:1215-1232. [PMID: 35077653 DOI: 10.1080/17435390.2021.2011974] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The main role of mitochondria is to generate the energy necessary for the cell to survive and adapt to different environmental stresses. Energy demand varies depending on the phenotype of the cell. To efficiently meet metabolic demands, mitochondria require a specific proton homeostasis and defined membrane structures to facilitate adenosine triphosphate production. This homeostatic environment is constantly challenged as mitochondria are a major target for damage after exposure to environmental contaminants. Here we report changes in mitochondrial structure profiles in different cell types using electron microscopy in response to particle stress exposure in three different representative lung cell types. Endpoint analyses include nanoparticle intracellular uptake; quantitation of mitochondrial size, shape, and ultrastructure; and confirmation of autophagosome formation. Results show that low-dose aluminum nanoparticles exposure (1 ppm; 1 µg/mL; 1.6 × 1 0-7 µg/cell)) to primary and asthma cells incurred significant mitochondrial deformation and increases in mitophagy, while cancer cells exhibited only slight changes in mitochondrial morphology and an increase in lipid body formation. These results show low-dose aluminum nanoparticle exposure induces subtle changes in the mitochondria of specific lung cells that can be quantified with microscopy techniques. Furthermore, within the lung, cell type by the nature of origin (i.e. primary vs. cancer vs. asthma) dictates mitochondrial morphology, metabolic health, and the metabolic stress response of the cell.
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Affiliation(s)
- Henry Lujan
- Department of Environmental Science, Baylor University, Waco, TX, USA
| | - Marina R Mulenos
- Department of Environmental Science, Baylor University, Waco, TX, USA
| | - Desirae Carrasco
- Department of Environmental Science, Baylor University, Waco, TX, USA
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, TX, USA
| | - Saber M Hussain
- Biotechnology Branch, Airman Biosciences Division, 711th Human Performance Wing, Air Force Research Laboratory, Dayton, OH, USA
| | - Christie M Sayes
- Department of Environmental Science, Baylor University, Waco, TX, USA
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14
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Milligan JN, Flynn AG, Wagner JD, Kouwenberg LL, Barclay RS, Byars BW, Dunn RE, White JD, Zechmann B, Peppe DJ. Quantifying the effect of shade on cuticle morphology and carbon isotopes of sycamores: present and past. Am J Bot 2021; 108:2435-2451. [PMID: 34636420 PMCID: PMC9306692 DOI: 10.1002/ajb2.1772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 09/16/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
PREMISE Reconstructing the light environment and architecture of the plant canopy from the fossil record requires the use of proxies, such as those derived from cell wall undulation, cell size, and carbon isotopes. All approaches assume that plant taxa will respond predictably to changes in light environments. However, most species-level studies looking at cell wall undulation only consider "sun" or "shade" leaves; therefore, we need a fully quantitative taxon-specific method. METHODS We quantified the response of cell wall undulation, cell size, and carbon isotopes of Platanus occidentalis using two experimental setups: (1) two growth chambers at low and high light and (2) a series of outdoor growth experiments using green and black shade cloth at different densities. We then developed and applied a proxy for daily light integral (DLI) to fossil Platanites leaves from two early Paleocene floras from the San Juan Basin in New Mexico. RESULTS All traits responded to light environment. Cell wall undulation was the most useful trait for reconstructing DLI in the geological record. Median reconstructed DLI from early Paleocene leaves was ~44 mol m-2 d-1 , with values from 28 to 54 mol m-2 d-1 . CONCLUSIONS Cell wall undulation of P. occidentalis is a robust, quantifiable measurement of light environment that can be used to reconstruct the paleo-light environment from fossil leaves. The distribution of high DLI values from fossil leaves may provide information on canopy architecture; indicating that either (1) most of the canopy mass is within the upper portion of the crown or (2) leaves exposed to more sunlight are preferentially preserved.
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Affiliation(s)
- Joseph N. Milligan
- Terrestrial Paleoclimatology Research Group, Department of GeosciencesBaylor UniversityWacoTXUSA
| | - Andrew G. Flynn
- Terrestrial Paleoclimatology Research Group, Department of GeosciencesBaylor UniversityWacoTXUSA
| | - Jennifer D. Wagner
- Department of Integrative BiologyUniversity of California Berkeley, and UC Museum of PaleontologyBerkeleyCAUSA
| | | | - Richard S. Barclay
- Department of PaleobiologyNational Museum of Natural History, Smithsonian Institution, 10th & Constitution Avenue NWWashingtonD.C.USA
| | | | - Regan E. Dunn
- Natural History Museums of Los Angeles County, La Brea Tar PitsLos AngelesCAUSA
| | | | - Bernd Zechmann
- Center for Microscopy and ImagingBaylor UniversityWacoTXUSA
| | - Daniel J. Peppe
- Terrestrial Paleoclimatology Research Group, Department of GeosciencesBaylor UniversityWacoTXUSA
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15
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Zechmann B, Müller M, Möstl S, Zellnig G. Three-dimensional quantitative imaging of Tobacco mosaic virus and Zucchini yellow mosaic virus induced ultrastructural changes. Protoplasma 2021; 258:1201-1211. [PMID: 33619654 DOI: 10.1007/s00709-021-01626-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [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: 10/27/2020] [Accepted: 02/12/2021] [Indexed: 06/12/2023]
Abstract
Two-dimensional ultrastructural changes of Tobacco mosaic virus (TMV) and Zucchini yellow mosaic virus (ZYMV) in tobacco and pumpkin plants, respectively, are well studied. To provide 3D data, representative control and infected cells were reconstructed using serial sectioning and transmission electron microscopy. Quantitative data of 3D ultrastructural changes were then extracted from the cytosol and organelles by image analysis. While TMV induced the accumulation of an average of 40 virus inclusion bodies in the cytosol, which covered about 13% of the cell volume, ZYMV caused the accumulation of an average of 1752 cylindrical inclusions in the cytosol, which covered about 2.7% of the total volume of the cell. TMV infection significantly decreased the number and size of mitochondria (- 49 and - 20%) and peroxisomes (- 62 and - 28%) of the reconstructed cell. The reconstructed ZYMV-infected cell contained more (105%) and larger (109%) mitochondria when compared to the control cell. While the reconstructed TMV-infected cell contained larger (20%) and the ZYMV-infected smaller (19%) chloroplasts, both contained less chloroplasts (- 40% for TMV and - 23% for ZYMV). In chloroplasts, the volume of starch and plastoglobules increased (664% and 150% for TMV and 1324% and 1300% for ZYMV) when compared to the control. The latter was correlated with a decrease in the volume of thylakoids in the reconstructed ZYMV-infected cell (- 31%) indicating that degradation products from thylakoids are transported and stored in plastoglobules. Summing up, the data collected in this study give a comprehensive overview of 3D changes induced by TMV and ZYMV in plants.
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Affiliation(s)
- Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, One Bear Place #97046, Waco, TX, 76798, USA.
| | - Maria Müller
- Institute of Biology, Plant Sciences, University of Graz, NAWI Graz, Schubertstrasse 51, 8010, Graz, Austria
| | - Stefan Möstl
- Institute of Biology, Plant Sciences, University of Graz, NAWI Graz, Schubertstrasse 51, 8010, Graz, Austria
| | - Günther Zellnig
- Institute of Biology, Plant Sciences, University of Graz, NAWI Graz, Schubertstrasse 51, 8010, Graz, Austria
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16
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Wilburn DT, Machek SB, Zechmann B, Willoughby DS. Comparison of skeletal muscle ultrastructural changes between normal and blood flow-restricted resistance exercise: A case report. Exp Physiol 2021; 106:2177-2184. [PMID: 34438467 DOI: 10.1113/ep089858] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 06/22/2021] [Accepted: 08/16/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the main observation in this case? The main observation of this case report is that blood flow-restricted exercise can cause myofibrils to have an aberrant wave-like appearance that is accompanied by irregular pockets of sarcoplasm in the intermyofibrillar space, while traditional forms of damage to the Z-discs and contractile elements are not as apparent. What insights does it reveal? Our findings indicate that blood flow restriction-mediated fluid pooling might cause alterations in skeletal muscle ultrastructure after exercise that might be directly related to myofibre swelling. ABSTRACT The acute effects of blood flow-restricted (BFR) exercise training on skeletal muscle ultrastructure are poorly understood owing to inconsistent findings and the use of largely imprecise systemic markers for indications of muscle damage. The purpose of this study was to compare myofibrillar ultrastructure before and 30 min after normal and BFR resistance exercise using transmission electron microscopy in a single individual to evaluate the feasibility of this more nuanced approach. One apparently healthy male with 13 years of resistance exercise completed six sets of both BFR [30% of one-repetition maximum (1-RM)] and normal non-occluded (70% of 1-RM) unilateral angled leg press on the contralateral leg, as a control, after assessment of 1-RM 72 h before. Vastus lateralis muscle biopsies were collected before and 30 min after each exercise session. The lengths and widths of 250 sarcomeres and the sarcoplasmic area were assessed via 20 individual transmission electron photomicrographs. Analysis revealed that BFR training (1.769 ± 0.12 μm) increased sarcomere length when compared with normal exercise (1.64 ± 0.17 μm; P < 0.001), without differences in sarcomere width between conditions (BFR, 0.90 ± 0.26 μm; normal, 0.93 ± 0.27 μm; P = 0.172). Furthermore, there were no significant interaction (P = 0.168) or condition effects between BFR (25.98 ± 4.17%) and normal (27.3 ± 6.49%) resistance exercise for sarcoplasmic area (P = 0.229). Exercise also increased sarcoplasmic area within the myofibril (pre-exercise, 24.42 ± 5.13%; postexercise, 28.95 ± 5.92%) for both conditions (P = 0.001). This case study demonstrates a unique BFR training-induced alteration in myofibril ultrastructure that appeared wave like and was accompanied by intracellular abnormalities that appeared to be fluid pockets of sarcoplasm disrupting the surrounding myofibrils.
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Affiliation(s)
- Dylan T Wilburn
- Exercise & Biochemical Nutrition Laboratory, Department of Health, Human Performance & Recreation, Robbins College of Health and Human Sciences, Baylor University, Waco, Texas, USA
| | - Steven B Machek
- Exercise & Biochemical Nutrition Laboratory, Department of Health, Human Performance & Recreation, Robbins College of Health and Human Sciences, Baylor University, Waco, Texas, USA
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, Texas, USA
| | - Darryn S Willoughby
- School of Exercise and Sport Science, University of Mary Hardin-Baylor, Belton, Texas, USA
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17
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Vojvodić S, Luković JD, Zechmann B, Jevtović M, Pristov JB, Stanić M, Lizzul AM, Pittman JK, Spasojević I. The effects of ionizing radiation on the structure and antioxidative and metal-binding capacity of the cell wall of microalga Chlorella sorokiniana. Chemosphere 2020; 260:127553. [PMID: 32653748 DOI: 10.1016/j.chemosphere.2020.127553] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 03/27/2020] [Revised: 06/20/2020] [Accepted: 06/28/2020] [Indexed: 06/11/2023]
Abstract
The impact of ionizing radiation on microorganisms such as microalgae is a topic of increasing importance for understanding the dynamics of aquatic ecosystems in response to environmental radiation, and for the development of efficient approaches for bioremediation of mining and nuclear power plants wastewaters. Currently, nothing is known about the effects of ionizing radiation on the microalgal cell wall, which represents the first line of defence against chemical and physical environmental stresses. Using various microscopy, spectroscopy and biochemical techniques we show that the unicellular alga Chlorella sorokiniana elicits a fast response to ionizing radiation. Within one day after irradiation with doses of 1-5 Gy, the fibrilar layer of the cell wall became thicker, the fraction of uronic acids was higher, and the capacity to remove the main reactive product of water radiolysis increased. In addition, the isolated cell wall fraction showed significant binding capacity for Cu2+, Mn2+, and Cr3+. The irradiation further increased the binding capacity for Cu2+, which appears to be mainly bound to glucosamine moieties within a chitosan-like polymer in the outer rigid layer of the wall. These results imply that the cell wall represents a dynamic structure that is involved in the protective response of microalgae to ionizing radiation. It appears that microalgae may exhibit a significant control of metal mobility in aquatic ecosystems via biosorption by the cell wall matrix.
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Affiliation(s)
- Snežana Vojvodić
- Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia.
| | - Jelena Danilović Luković
- Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia; Institute for Application of Nuclear Energy, University of Belgrade, Banatska 31b, 11080, Belgrade-Zemun, Serbia.
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, One Bear Place 97046, Waco, TX, USA.
| | - Mima Jevtović
- Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia; Faculty of Chemistry, University of Belgrade, Studentski Trg 12-16, 11001, Belgrade, Serbia.
| | - Jelena Bogdanović Pristov
- Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia.
| | - Marina Stanić
- Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia.
| | | | - Jon K Pittman
- Department of Earth and Environmental Sciences, School of Natural Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.
| | - Ivan Spasojević
- Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia.
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Matthaeus WJ, Schmidt J, White JD, Zechmann B. Novel perspectives on stomatal impressions: Rapid and non-invasive surface characterization of plant leaves by scanning electron microscopy. PLoS One 2020; 15:e0238589. [PMID: 32881951 PMCID: PMC7470294 DOI: 10.1371/journal.pone.0238589] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 08/19/2020] [Indexed: 11/18/2022] Open
Abstract
Scanning electron microscopy (SEM) is widely used to investigate the surface morphology, and physiological state of plant leaves. Conventionally used methods for sample preparation are invasive, irreversible, require skill and expensive equipment, and are time and labor consuming. This study demonstrates a method to obtain in vivo surface information of plant leaves by imaging replicas with SEM that is rapid and non-invasive. Dental putty was applied to the leaves for 5 minutes and then removed. Replicas were then imaged with SEM and compared to fresh leaves, and leaves that were processed conventionally by chemical fixation, dehydration and critical point drying. The surface structure of leaves was well preserved on the replicas. The outline of epidermal as well as guard cells could be clearly distinguished enabling determination of stomatal density. Comparison of the dimensions of guard cells revealed that replicas did not differ from fresh leaves, while conventional sample preparation induced strong shrinkage (-40% in length and -38% in width) of the cells when compared to guard cells on fresh leaves. Tilting the replicas enabled clear measurement of stomatal aperture dimensions. Summing up, the major advantages of this method are that it is inexpensive, non-toxic, simple to apply, can be performed in the field, and that results on stomatal density and in vivo stomatal dimensions in 3D can be obtained in a few minutes.
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Affiliation(s)
| | - Jonathan Schmidt
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Joseph D. White
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, Texas, United States of America
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19
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Harris D, Taylor KP, Napierkowski K, Zechmann B. Indoor Finish Material Influence on Contamination, Transmission, and Eradication of Methicillin-Resistant Staphylococcus aureus (MRSA). HERD 2020; 14:118-129. [PMID: 32867539 PMCID: PMC7464060 DOI: 10.1177/1937586720952892] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Objective: The purpose of this study was to evaluate environmental surface materials used in healthcare environments for material composition, methicillin-resistant Staphylococcus aureus (MRSA) viability, and a comparison of two disinfectants, a bleach germicidal cleaner and Decon7, a novel disinfectant. Background: Contaminated environmental surfaces have been associated with outbreaks of healthcare-associated illness (HAIs). One in every 20 patients in U.S. acute care hospitals acquire a healthcare-associated illness, leading to consequences such as elevated morbidity, mortality, and a decrease in quality of life. In the patient environment, MRSA can remain viable from hours to up to 14 days. Methods: Environmental surface materials were evaluated as new and worn. Material composition and properties were assessed to evaluate surface integrity and the influence on the disinfection of MRSA. Inoculated materials were used to assess MRSA viability over time and the efficacy of a manufacturer’s recommended cleaning and disinfection product compared to a novel disinfectant. Results: Environmental surface materials respond differently in appearance and roughness, when mechanically worn. When measuring MRSA survival, at 24 hr, MRSA colony forming unit (CFU) counts were reduced on the copper sheet surface and solid surface with cupric oxide. By 72 hr, all MRSA counts were zero. Bleach and the novel disinfectant were equally effective at disinfecting MRSA from all surface types. Conclusions: This study highlights a gap in knowledge about the impact of type and wear of environmental surface materials used in healthcare environments on contamination with epidemiologically important organisms. In conclusion, environmental surface material wear, properties, and cleaning and disinfection efficacy are important factors to consider when addressing HAIs.
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Affiliation(s)
- Debra Harris
- Human Sciences and Design, College of Health and Human Sciences, 14643Baylor University, Waco, TX, USA
| | - Keyanna P Taylor
- College of Health and Human Sciences, 14643Baylor University, Waco, TX, USA
| | | | - Bernd Zechmann
- Center for Microscopy and Imaging, 14643Baylor University, Waco, TX, USA
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20
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Zechmann B. Subcellular Roles of Glutathione in Mediating Plant Defense during Biotic Stress. Plants (Basel) 2020; 9:plants9091067. [PMID: 32825274 PMCID: PMC7569779 DOI: 10.3390/plants9091067] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/12/2020] [Accepted: 08/19/2020] [Indexed: 12/17/2022]
Abstract
Glutathione and reactive oxygen species (ROS) play important roles, within different cell compartments, in activating plant defense and the development of resistance. In mitochondria, the accumulation of ROS and the change of glutathione towards its oxidized state leads to mitochondrial dysfunction, activates cell death, and triggers resistance. The accumulation of glutathione in chloroplasts and peroxisomes at the early stages of plant pathogen interactions is related to increased tolerance and resistance. The collapse of the antioxidative system in these two cell compartments at the later stages leads to cell death through retrograde signaling. The cytosol can be considered to be the switchboard during biotic stress where glutathione is synthesized, equally distributed to, and collected from different cell compartments. Changes in the redox state of glutathione and the accumulation of ROS in the cytosol during biotic stress can initiate the activation of defense genes in nuclei through pathways that involve salicylic acid, jasmonic acid, auxins, and abscisic acid. This review dissects the roles of glutathione in individual organelles during compatible and incompatible bacterial, fungal, and viral diseases in plants and explores the subcelluar roles of ROS, glutathione, ascorbate, and related enzymes in the development of resistance.
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Affiliation(s)
- Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, One Bear Place #97046, Waco, TX 76798, USA
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21
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Mulenos MR, Zechmann B, Sayes CM. Sample preparation utilizing sputter coating increases contrast of cellulose nanocrystals in the transmission electron microscope. Microscopy (Oxf) 2019; 68:471-474. [PMID: 31696231 DOI: 10.1093/jmicro/dfz032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 03/07/2019] [Revised: 07/12/2019] [Accepted: 07/17/2019] [Indexed: 11/14/2022] Open
Abstract
Cellulose nanocrystals (CNCs) are prepared for transmission electron microscopy (TEM) using positive or negative stains in an effort to increase the contrast between the specimen and background. When imaging CNCs, conventional stains have been shown to induce particle aggregation and produce artifacts. In this study, we report on methods used to image CNCs. To increase contrast and decrease artifacts and aggregation, sputter coating was used to coat the samples. CNCs were loaded onto copper grids and sputter coated with one of four different metals: iridium, carbon, gold, and titanium. The final layer was deposited at 5 nm to ensure surface homogeneity. The thin layer of conductive metal atoms deposited onto the specimen surface significantly increased contrast and improved image quality. The results presented here demonstrate the advantages of using sputter coating for imaging of highly crystalline cellulose materials with TEM.
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Affiliation(s)
- Marina R Mulenos
- Department of Environmental Science, Baylor University, Waco, 76798 TX, USA and
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, 76798 TX, USA
| | - Christie M Sayes
- Department of Environmental Science, Baylor University, Waco, 76798 TX, USA and
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22
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Marty L, Bausewein D, Müller C, Bangash SAK, Moseler A, Schwarzländer M, Müller-Schüssele SJ, Zechmann B, Riondet C, Balk J, Wirtz M, Hell R, Reichheld JP, Meyer AJ. Arabidopsis glutathione reductase 2 is indispensable in plastids, while mitochondrial glutathione is safeguarded by additional reduction and transport systems. New Phytol 2019; 224:1569-1584. [PMID: 31372999 DOI: 10.1111/nph.16086] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/23/2019] [Indexed: 05/27/2023]
Abstract
A highly negative glutathione redox potential (EGSH ) is maintained in the cytosol, plastids and mitochondria of plant cells to support fundamental processes, including antioxidant defence, redox regulation and iron-sulfur cluster biogenesis. Out of two glutathione reductase (GR) proteins in Arabidopsis, GR2 is predicted to be dual-targeted to plastids and mitochondria, but its differential roles in these organelles remain unclear. We dissected the role of GR2 in organelle glutathione redox homeostasis and plant development using a combination of genetic complementation and stacked mutants, biochemical activity studies, immunogold labelling and in vivo biosensing. Our data demonstrate that GR2 is dual-targeted to plastids and mitochondria, but embryo lethality of gr2 null mutants is caused specifically in plastids. Whereas lack of mitochondrial GR2 leads to a partially oxidised glutathione pool in the matrix, the ATP-binding cassette (ABC) transporter ATM3 and the mitochondrial thioredoxin system provide functional backup and maintain plant viability. We identify GR2 as essential in the plastid stroma, where it counters GSSG accumulation and developmental arrest. By contrast a functional triad of GR2, ATM3 and the thioredoxin system in the mitochondria provides resilience to excessive glutathione oxidation.
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Affiliation(s)
- Laurent Marty
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld, 360, D-69120, Heidelberg, Germany
| | - Daniela Bausewein
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld, 360, D-69120, Heidelberg, Germany
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Friedrich-Ebert-Allee 144, D-53113, Bonn, Germany
| | - Christopher Müller
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld, 360, D-69120, Heidelberg, Germany
| | - Sajid Ali Khan Bangash
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Friedrich-Ebert-Allee 144, D-53113, Bonn, Germany
| | - Anna Moseler
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Friedrich-Ebert-Allee 144, D-53113, Bonn, Germany
| | - Markus Schwarzländer
- Institute for Biology and Biotechnology of Plants, University of Münster, Schlossplatz 8, D-48143, Münster, Germany
| | - Stefanie J Müller-Schüssele
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Friedrich-Ebert-Allee 144, D-53113, Bonn, Germany
| | - Bernd Zechmann
- Center of Microscopy and Imaging, Baylor University, One Bear Place 97046, Waco, TX, 76798-7046, USA
| | - Christophe Riondet
- Laboratoire Génome et Développement des Plantes, Université de Perpignan, Via Domitia, F-66860, Perpignan, France
- Laboratoire Génome et Développement des Plantes, CNRS, F-66860, Perpignan, France
| | - Janneke Balk
- John Innes Centre and University of East Anglia, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Markus Wirtz
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld, 360, D-69120, Heidelberg, Germany
| | - Rüdiger Hell
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld, 360, D-69120, Heidelberg, Germany
| | - Jean-Philippe Reichheld
- Laboratoire Génome et Développement des Plantes, Université de Perpignan, Via Domitia, F-66860, Perpignan, France
- Laboratoire Génome et Développement des Plantes, CNRS, F-66860, Perpignan, France
| | - Andreas J Meyer
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Friedrich-Ebert-Allee 144, D-53113, Bonn, Germany
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Abstract
Plastids perform many essential functions in plant metabolism including photosynthesis, synthesis of metabolites, and stress signaling. The most prominent type in green leaves is the chloroplast which contains thylakoids, plastoglobules, and starch. As these structures are closely linked to the metabolism of chloroplasts, changes during plant growth and development and during environmental stress situations are likely to occur. The aim of this study was to characterize changes in size and ultrastructure of chloroplast on cross-sections of leaves during high light stress, Botrytis infection, and dark induced senescence by quantitative transmission electron microscopy (TEM).The size of chloroplasts on cross sections of leaves decreased significantly when plants were subject to high light (49%), Botrytis infection (58%), and senescence (71%). The number of chloroplasts on cross sections of the palisade cell layer and spongy parenchyma, respectively, decreased significantly in plants exposed to high light conditions (48% and 29%), infected with Botrytis (48% and 46%), and during senescence (78% and 80%). Thylakoids on cross-sections of chloroplasts decreased significantly in plants exposed to high light (22%), inoculated with Botrytis cinerea (36%), and senescence (51%). This correlated with a massive increase in plastoglobules on cross-sections of chloroplasts of 88%, 2,306% and 19,617%, respectively. Starch contents on cross sections of chloroplasts were completely diminished in all three stress scenarios. These results demonstrate that the decrease in the number and size of chloroplasts is a reliable stress marker in plants during abiotic and biotic stress situations which can be easily detected with a light microscope. Further, lack of starch, the occurrence of large plastoglobules and decrease in thylakoids can also be regarded as reliable stress marker in plants which can be detected by TEM.
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Affiliation(s)
- Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, Texas, United States of America
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24
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Wiest LA, Ferraro JV, Binetti KM, Forman SL, Esker DA, Kibunjia M, Brugal JP, Zechmann B. Morphological characteristics of preparator air-scribe marks: Implications for taphonomic research. PLoS One 2018; 13:e0209330. [PMID: 30571785 PMCID: PMC6301663 DOI: 10.1371/journal.pone.0209330] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 12/04/2018] [Indexed: 11/21/2022] Open
Abstract
Taphonomic analyses of bone-surface modifications can provide key insights into past biotic involvement with animal remains, as well as elucidate the context(s) of other biostratinomic (pre-burial) processes, diagenesis, excavation, preparation and storage. Such analyses, however, first require researchers to rigorously disambiguate between continuums of damage morphologies prior to attributing individual marks to specific actors and effectors (e.g., carnivore tooth, stone tool cutting edge, etc.). To date, a number of bone-modifying agents have been identified, and criteria for identifying their traces have been published. Relatively little research, however, has focused on bone-surface modifications imparted during specimen preparation. Herein we report that air scribes, small pneumatic tools commonly used for preparation in museum contexts, can generate unintentional marks that may mimic surficial modification caused by carnivores. To aid investigators in assessing the hypothesis that a mark in question is derived from air-scribe preparation activities, we provide high-resolution, detailed morphological information imaged with scanning electron microscopy (SEM). The main diagnostic characteristic of air-scribe damage is the occurrence of sequential, variously spaced, sub-millimeter scallop-like stepped bone removals. This morphology can resemble damage imparted by carnivore teeth. In contrast to marks produced by trampling, stone tools and carnivores, however, no continuous internal features, such as linear microstriations, were observed within grooves produced by the air scribe. Thus, the presence of such features can be used to disprove an air-scribe origin. A culmination of the morphological criteria presented herein, cross-cutting relationships with other surficial features (e.g., diagenetic discoloration, weathering textures), the position of occurrence, and an overall contextual framework for the assemblage is suggested for accurate identification of such traces. The ability to recognize or disprove air-scribe damage will allow researchers to confidently proceed with interpreting past biological and sedimentological interactions with animal remains.
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Affiliation(s)
- Logan A. Wiest
- Department of Geosciences, and Institute of Archaeology, Baylor University, Waco, Texas, United States of America
- * E-mail:
| | - Joseph V. Ferraro
- Department of Anthropology, and Institute of Archaeology, Baylor University, Waco, Texas, United States of America
| | - Katie M. Binetti
- Department of Anthropology, and Institute of Archaeology, Baylor University, Waco, Texas, United States of America
| | - Steven L. Forman
- Department of Geosciences, and Institute of Archaeology, Baylor University, Waco, Texas, United States of America
| | - Donald A. Esker
- Department of Geosciences, and Institute of Archaeology, Baylor University, Waco, Texas, United States of America
| | | | - Jean-Philip Brugal
- Aix Marseille University, CNRS, Ministère de la Culture, UMR 7269 LAMPEA, Aix-en-Provence, France
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, Texas, United States of America
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25
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Abstract
SIGNIFICANCE Ascorbate is an essential antioxidant in plants. Total contents and its redox state in organelles are crucial to fight and signal oxidative stress. Recent Advances: With quantitative immunoelectron microscopy and biochemical methods, highest ascorbate contents have recently been measured in peroxisomes (23 mM) and the cytosol (22 mM), lowest ones in vacuoles (2 mM), and intermediate concentrations (4-16 mM) in all other organelles. CRITICAL ISSUES The accumulation of ascorbate in chloroplasts and peroxisomes is crucial for plant defense. Its depletion in chloroplasts, peroxisomes, and mitochondria during biotic stress leads to the accumulation of reactive oxygen species (ROS) and the development of chlorosis and necrosis. In the apoplast and vacuoles, ascorbate is the most important antioxidant for the detoxification of ROS. The cytosol acts as a hub for ascorbate metabolism as it reduces its oxidized forms that are produced in the cytosol or imported from other cell compartments. It is a sink for ascorbate that is produced in mitochondria, distributes ascorbate to all organelles, and uses ascorbate to detoxify ROS. As ascorbate and its redox state are involved in protein synthesis and modifications, it can be concluded that ascorbate in the cytosol senses oxidative stress and regulates plant growth, development, and defense. FUTURE DIRECTIONS Future research should focus on (1) dissecting roles of ascorbate in vacuoles and the lumen of the endoplasmic reticulum, (2) identifying the physiological relevance of ascorbate transporters, and (3) correlating current data with changes in the subcellular distribution of related enzymes, ROS, and gene expression patterns.
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Affiliation(s)
- Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University , Waco, Texas
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26
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Nottensteiner M, Zechmann B, McCollum C, Hückelhoven R. A barley powdery mildew fungus non-autonomous retrotransposon encodes a peptide that supports penetration success on barley. J Exp Bot 2018; 69:3745-3758. [PMID: 29757394 PMCID: PMC6022598 DOI: 10.1093/jxb/ery174] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [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: 01/31/2018] [Accepted: 05/09/2018] [Indexed: 05/22/2023]
Abstract
Pathogens overcome plant immunity by means of secreted effectors. Host effector targets often act in pathogen defense, but might also support fungal accommodation or nutrition. The barley ROP GTPase HvRACB is involved in accommodation of fungal haustoria of the powdery mildew fungus Blumeria graminis f.sp. hordei (Bgh) in barley epidermal cells. We found that HvRACB interacts with the ROP-interactive peptide 1 (ROPIP1) that is encoded on the active non-long terminal repeat retroelement Eg-R1 of Bgh. Overexpression of ROPIP1 in barley epidermal cells and host-induced post-transcriptional gene silencing (HIGS) of ROPIP1 suggested that ROPIP1 is involved in virulence of Bgh. Bimolecular fluorescence complementation and co-localization supported that ROPIP1 can interact with activated HvRACB in planta. We show that ROPIP1 is expressed by Bgh on barley and translocated into the cytoplasm of infected barley cells. ROPIP1 is recruited to microtubules upon co-expression of MICROTUBULE ASSOCIATED ROP GTPase ACTIVATING PROTEIN (HvMAGAP1) and can destabilize cortical microtubules. The data suggest that Bgh ROPIP targets HvRACB and manipulates host cell microtubule organization for facilitated host cell entry. This points to a possible neo-functionalization of retroelement-derived transcripts for the evolution of a pathogen virulence effector.
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Affiliation(s)
- Mathias Nottensteiner
- Chair of Phytopathology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, TX, USA
| | - Christopher McCollum
- Chair of Phytopathology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Ralph Hückelhoven
- Chair of Phytopathology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
- Correspondence:
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27
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Ma LS, Wang L, Trippel C, Mendoza-Mendoza A, Ullmann S, Moretti M, Carsten A, Kahnt J, Reissmann S, Zechmann B, Bange G, Kahmann R. The Ustilago maydis repetitive effector Rsp3 blocks the antifungal activity of mannose-binding maize proteins. Nat Commun 2018; 9:1711. [PMID: 29703884 PMCID: PMC5923269 DOI: 10.1038/s41467-018-04149-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 04/06/2018] [Indexed: 12/22/2022] Open
Abstract
To cause disease in maize, the biotrophic fungus Ustilago maydis secretes a large arsenal of effector proteins. Here, we functionally characterize the repetitive effector Rsp3 (repetitive secreted protein 3), which shows length polymorphisms in field isolates and is highly expressed during biotrophic stages. Rsp3 is required for virulence and anthocyanin accumulation. During biotrophic growth, Rsp3 decorates the hyphal surface and interacts with at least two secreted maize DUF26-domain family proteins (designated AFP1 and AFP2). AFP1 binds mannose and displays antifungal activity against the rsp3 mutant but not against a strain constitutively expressing rsp3. Maize plants silenced for AFP1 and AFP2 partially rescue the virulence defect of rsp3 mutants, suggesting that blocking the antifungal activity of AFP1 and AFP2 by the Rsp3 effector is an important virulence function. Rsp3 orthologs are present in all sequenced smut fungi, and the ortholog from Sporisorium reilianum can complement the rsp3 mutant of U. maydis, suggesting a novel widespread fungal protection mechanism. The fungus Ustilago maydis secretes many effector proteins to cause disease in maize. Here, Ma et al. show that the repetitive effector Rsp3 is required for virulence by inhibiting the antifungal activity of two mannose-binding proteins that are secreted by the plant cells.
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Affiliation(s)
- Lay-Sun Ma
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Lei Wang
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.,Department of Pharmacology, Max Planck Institute for Heart and Lung Research, 61231, Bad Nauheim, Germany
| | - Christine Trippel
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.,Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University-Göttingen, 37077, Göttingen, Germany
| | - Artemio Mendoza-Mendoza
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.,Bio-Protection Research Centre, Lincoln University, PO Box 64, Lincoln, 7647, New Zealand
| | - Steffen Ullmann
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.,, Düsseldorfer Straße 177, 45481, Mülheim an der Ruhr, Germany
| | - Marino Moretti
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Alexander Carsten
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Jörg Kahnt
- Mass Spectroscopy Facility, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Stefanie Reissmann
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Bernd Zechmann
- Center for Microscopy and Imaging (CMI), Baylor University, Waco, Texas, 76798-7046, USA
| | - Gert Bange
- LOEWE Center for Synthetic Microbiology and Faculty of Chemistry, Philipps-Universität Marburg, 35032 Marburg, Germany
| | - Regine Kahmann
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.
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28
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Gueldner J, Zhang F, Zechmann B, Bruce ED. Evaluating a novel oxygenating therapeutic for its potential use in the advancement of wound healing. Toxicol In Vitro 2017; 43:62-68. [PMID: 28599845 DOI: 10.1016/j.tiv.2017.06.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [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: 09/26/2016] [Revised: 06/03/2017] [Accepted: 06/05/2017] [Indexed: 12/29/2022]
Abstract
Non-gaseous oxygen therapeutics are emerging technologies in regenerative medicine that aim to sidestep the undesirable effects seen in traditional oxygen therapies, while enhancing tissue and wound regeneration. Using a novel oxygenating therapeutic (Ox66™) several in vitro models including fibroblast and keratinocyte monocultures were evaluated for potential drug toxicity, the ability of cells to recover after chemical injury, and cell migration after scratch assay. It was determined that in both cell lines, there was no significant cytotoxicity found after independent treatment with Ox66™. Similarly, after DMSO-induced chemical injury, the health parameters of cells treated with Ox66™ were improved when compared to their untreated counterparts. Particles were also characterized using scanning electron microscopy and electron dispersive spectroscopy both individually and in conjunction with fibroblast growth. The data in this study showed that the novel wound healing therapeutic has potential in advancing the treatment of various types of acute and chronic wounds.
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Affiliation(s)
- Jennifer Gueldner
- Baylor University, Institute of Biomedical Studies, One Bear Place #97266, Waco, TX. 76798, United States
| | - Fan Zhang
- Baylor University, Department of Environmental Science, One Bear Place #97266, Waco, TX 76798, United States
| | - Bernd Zechmann
- Baylor University, Center for Microscopy and Imaging, One Bear Place #97046, Waco, TX 76798, United States
| | - Erica D Bruce
- Baylor University, Institute of Biomedical Studies, Department of Environmental Science, The Institute of Ecological, Earth and Environmental Sciences, One Bear Place #97266, Waco, TX. 76798, United States.
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29
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Mohring F, Rahbari M, Zechmann B, Rahlfs S, Przyborski JM, Meyer AJ, Becker K. Determination of glutathione redox potential and pH value in subcellular compartments of malaria parasites. Free Radic Biol Med 2017; 104:104-117. [PMID: 28062360 DOI: 10.1016/j.freeradbiomed.2017.01.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 12/16/2016] [Accepted: 01/02/2017] [Indexed: 12/26/2022]
Abstract
The malaria parasite Plasmodium falciparum is exposed to multiple sources of oxidative challenge during its complex life cycle in the Anopheles vector and its human host. In order to further elucidate redox-based parasite host cell interactions and mechanisms of drug action, we targeted the genetically encoded glutathione redox sensor roGFP2 coupled to human glutaredoxin 1 (roGFP2-hGrx1) as well as the ratiometric pH sensor pHluorin to the apicoplast and the mitochondrion of P. falciparum. Using live cell imaging, this allowed for the first time the determination of the pH values of the apicoplast (7.12±0.40) and mitochondrion (7.37±0.09) in the intraerythrocytic asexual stages of the parasite. Based on the roGFP2-hGrx1 signals, glutathione-dependent redox potentials of -267mV and -328mV, respectively, were obtained. Employing these novel tools, initial studies on the effects of redox-active agents and clinically employed antimalarial drugs were carried out on both organelles.
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Affiliation(s)
- Franziska Mohring
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Mahsa Rahbari
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, 101 Bagby Ave., Waco, TX 76706, USA
| | - Stefan Rahlfs
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Jude M Przyborski
- Parasitology, Philipps University Marburg, Karl-von-Frisch Strasse 8, 35043 Marburg, Germany
| | - Andreas J Meyer
- INRES-Chemical Signalling, University of Bonn, Friedrich-Ebert-Allee 144, 53113 Bonn, Germany
| | - Katja Becker
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany.
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30
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Lo Presti L, Zechmann B, Kumlehn J, Liang L, Lanver D, Tanaka S, Bock R, Kahmann R. An assay for entry of secreted fungal effectors into plant cells. New Phytol 2017; 213:956-964. [PMID: 27716942 DOI: 10.1111/nph.14188] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [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: 05/24/2016] [Accepted: 08/05/2016] [Indexed: 05/23/2023]
Abstract
Successful colonization of plants by prokaryotic and eukaryotic pathogens requires active effector-mediated suppression of defense responses and host tissue reprogramming. Secreted effector proteins can either display their activity in the apoplast or translocate into host cells and function therein. Although characterized in bacteria, the molecular mechanisms of effector delivery by fungal phytopathogens remain elusive. Here we report the establishment of an assay that is based on biotinylation of effectors in the host cytoplasm as hallmark of uptake. The assay exploits the ability of the bacterial biotin ligase BirA to biotinylate any protein that carries a short peptide (Avitag). It is based on the stable expression of BirA in the cytoplasm of maize plants and on engineering of Ustilago maydis strains to secrete Avitagged effectors. We demonstrate translocation of a number of effectors in the U. maydis-maize system and show data that suggest that the uptake mechanism could be rather nonspecific The assay promises to be a powerful tool for the classification of effectors as well as for the functional study of effector uptake mechanism not only in the chosen system but more generally for systems where biotrophic interactions are established.
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Affiliation(s)
- Libera Lo Presti
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 10, 35043, Marburg, Germany
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, One Bear Place #97046, Waco, TX, 76798-7046, USA
| | - Jochen Kumlehn
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), OT Gatersleben, Corrensstrasse 3, 06466, Stadt Seeland, Germany
| | - Liang Liang
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 10, 35043, Marburg, Germany
| | - Daniel Lanver
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 10, 35043, Marburg, Germany
| | - Shigeyuki Tanaka
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 10, 35043, Marburg, Germany
| | - Ralph Bock
- Department of Organelle Biology, Biotechnology and Molecular Ecophysiology, Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Germany
| | - Regine Kahmann
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 10, 35043, Marburg, Germany
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31
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Vidović M, Morina F, Milić-Komić S, Vuleta A, Zechmann B, Prokić L, Veljović Jovanović S. Characterisation of antioxidants in photosynthetic and non-photosynthetic leaf tissues of variegated Pelargonium zonale plants. Plant Biol (Stuttg) 2016; 18:669-680. [PMID: 26712503 DOI: 10.1111/plb.12429] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [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: 11/26/2015] [Accepted: 12/22/2015] [Indexed: 06/05/2023]
Abstract
Hydrogen peroxide is an important signalling molecule, involved in regulation of numerous metabolic processes in plants. The most important sources of H2 O2 in photosynthetically active cells are chloroplasts and peroxisomes. Here we employed variegated Pelargonium zonale to characterise and compare enzymatic and non-enzymatic components of the antioxidative system in autotrophic and heterotrophic leaf tissues at (sub)cellular level under optimal growth conditions. The results revealed that both leaf tissues had specific strategies to regulate H2 O2 levels. In photosynthetic cells, the redox regulatory system was based on ascorbate, and on the activities of thylakoid-bound ascorbate peroxidase (tAPX) and catalase. In this leaf tissue, ascorbate was predominantly localised in the nucleus, peroxisomes, plastids and mitochondria. On the other hand, non-photosynthetic cells contained higher glutathione content, mostly located in mitochondria. The enzymatic antioxidative system in non-photosynthetic cells relied on the ascorbate-glutathione cycle and both Mn and Cu/Zn superoxide dismutase. Interestingly, higher content of ascorbate and glutathione, and higher activities of APX in the cytosol of non-photosynthetic leaf cells compared to the photosynthetic ones, suggest the importance of this compartment in H2 O2 regulation. Together, these results imply different regulation of processes linked with H2 O2 signalling at subcellular level. Thus, we propose green-white variegated leaves as an excellent system for examination of redox signal transduction and redox communication between two cell types, autotrophic and heterotrophic, within the same organ.
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Affiliation(s)
- M Vidović
- Institute for Multidisciplinary Research (IMSI), University of Belgrade, Belgrade, Serbia
| | - F Morina
- Institute for Multidisciplinary Research (IMSI), University of Belgrade, Belgrade, Serbia
| | - S Milić-Komić
- Institute for Multidisciplinary Research (IMSI), University of Belgrade, Belgrade, Serbia
| | - A Vuleta
- Institute for Biological Research 'Siniša Stanković', University of Belgrade, Belgrade, Serbia
| | - B Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, TX, USA
| | - Lj Prokić
- Faculty of Agriculture, University of Belgrade, Belgrade, Serbia
| | - S Veljović Jovanović
- Institute for Multidisciplinary Research (IMSI), University of Belgrade, Belgrade, Serbia
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32
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Luschin-Ebengreuth N, Zechmann B. Compartment-specific investigations of antioxidants and hydrogen peroxide in leaves of Arabidopsis thaliana during dark-induced senescence. Acta Physiol Plant 2016; 38:133. [PMID: 27217598 PMCID: PMC4859865 DOI: 10.1007/s11738-016-2150-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 02/04/2016] [Accepted: 04/19/2016] [Indexed: 05/13/2023]
Abstract
The aim of this study was to gain insight into the compartment-specific roles of ascorbate and glutathione in leaf senescence in Arabidopsis thaliana. The subcellular distribution of ascorbate, glutathione, and hydrogen peroxide (H2O2) was analyzed by transmission electron microscopy and correlated with the activity of antioxidative enzymes in wildtype plants and the ascorbate- and glutathione-deficient mutants vtc2-1 and pad2-1, respectively. Both mutants showed earlier and stronger senescence than the wildtype indicating the importance of a functioning ascorbate and glutathione cycle in the induction and regulation of senescence. Glutathione levels dropped drastically and up to 93 % in all cell compartments of wildtype plants and the vtc2-1 mutant within the first day of dark-induced senescence while ascorbate contents remained unchanged until the very end. Glutathione contents in mitochondria of pad2-1 mutants decreased more slowly over the first 7 days than compared to the other plants indicating an important role of glutathione in mitochondria in this mutant during senescence. The strongest decrease (84 %) of glutathione contents in wildtype plants at this time point was found in mitochondria indicating an important role of mitochondria for the induction of senescence and cell death events. Due to the general decrease of the antioxidative capacity, a strong accumulation of H2O2 was observed in cell walls, plastids, and the cytosol in all plants. Activities of glutathione reductase, dehydroascorbate reductase and catalase were strongly reduced while ascorbate peroxidase and monodehydroascorbate reductase were increased. The initial rapid drop of glutathione levels seemed to be the trigger for senescence, while ascorbate appeared to be the key factor in regulating senescence through controlling H2O2 levels by the oxidation of reduced ascorbate to monodehydroascorbate and the subsequent reduction to ascorbate by monodehydroascorbate reductase.
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Affiliation(s)
| | - Bernd Zechmann
- />Center for Microscopy and Imaging, Baylor University, One Bear Place #97046, Waco, TX 76798 USA
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Vidović M, Morina F, Milić S, Albert A, Zechmann B, Tosti T, Winkler JB, Jovanović SV. Carbon allocation from source to sink leaf tissue in relation to flavonoid biosynthesis in variegated Pelargonium zonale under UV-B radiation and high PAR intensity. Plant Physiol Biochem 2015; 93:44-55. [PMID: 25661975 DOI: 10.1016/j.plaphy.2015.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [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: 01/21/2015] [Accepted: 01/26/2015] [Indexed: 05/07/2023]
Abstract
We studied the specific effects of high photosynthetically active radiation (PAR, 400-700 nm) and ecologically relevant UV-B radiation (0.90 W m(-2)) on antioxidative and phenolic metabolism by exploiting the green-white leaf variegation of Pelargonium zonale plants. This is a suitable model system for examining "source-sink" interactions within the same leaf. High PAR intensity (1350 μmol m(-2) s(-1)) and UV-B radiation induced different responses in green and white leaf sectors. High PAR intensity had a greater influence on green tissue, triggering the accumulation of phenylpropanoids and flavonoids with strong antioxidative function. Induced phenolics, together with ascorbate, ascorbate peroxidase (APX, EC 1.11.1.11) and catalase (CAT, EC 1.11.1.6) provided efficient defense against potential oxidative pressure. UV-B-induced up-regulation of non-phenolic H2O2 scavengers in green leaf sectors was greater than high PAR-induced changes, indicating a UV-B role in antioxidative defense under light excess; on the contrary, minimal effects were observed in white tissue. However, UV-B radiation had greater influence on phenolics in white leaf sections compared to green ones, inducing accumulation of phenolic glycosides whose function was UV-B screening rather than antioxidative. By stimulation of starch and sucrose breakdown and carbon allocation in the form of soluble sugars from "source" (green) tissue to "sink" (white) tissue, UV-B radiation compensated the absence of photosynthetic activity and phenylpropanoid and flavonoid biosynthesis in white sectors.
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Affiliation(s)
- Marija Vidović
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11000 Belgrade, Serbia.
| | - Filis Morina
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11000 Belgrade, Serbia.
| | - Sonja Milić
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11000 Belgrade, Serbia.
| | - Andreas Albert
- Research Unit Environmental Simulation, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
| | - Bernd Zechmann
- Baylor University, Center for Microscopy and Imaging, One Bear Place #97046, Waco, TX 76798-7046, USA.
| | - Tomislav Tosti
- Faculty of Chemistry, University of Belgrade, PO Box 51, 11001 Belgrade, Serbia.
| | - Jana Barbro Winkler
- Research Unit Environmental Simulation, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
| | - Sonja Veljović Jovanović
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11000 Belgrade, Serbia.
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Wu H, Clay K, Thompson SS, Hennen-Bierwagen TA, Andrews BJ, Zechmann B, Gibbon BC. Pullulanase and Starch Synthase III Are Associated with Formation of Vitreous Endosperm in Quality Protein Maize. PLoS One 2015; 10:e0130856. [PMID: 26115014 PMCID: PMC4482715 DOI: 10.1371/journal.pone.0130856] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 05/25/2015] [Indexed: 11/25/2022] Open
Abstract
The opaque-2 (o2) mutation of maize increases lysine content, but the low seed density and soft texture of this type of mutant are undesirable. Lines with modifiers of the soft kernel phenotype (mo2) called “Quality Protein Maize” (QPM) have high lysine and kernel phenotypes similar to normal maize. Prior research indicated that the formation of vitreous endosperm in QPM might involve changes in starch granule structure. In this study, we focused on analysis of two starch biosynthetic enzymes that may influence kernel vitreousness. Analysis of recombinant inbred lines derived from a cross of W64Ao2 and K0326Y revealed that pullulanase activity had significant positive correlation with kernel vitreousness. We also found that decreased Starch Synthase III abundance may decrease the pullulanase activity and average glucan chain length given the same Zpu1 genotype. Therefore, Starch Synthase III could indirectly influence the kernel vitreousness by affecting pullulanase activity and coordinating with pullulanase to alter the glucan chain length distribution of amylopectin, resulting in different starch structural properties. The glucan chain length distribution had strong positive correlation with the polydispersity index of glucan chains, which was positively associated with the kernel vitreousness based on nonlinear regression analysis. Therefore, we propose that pullulanase and Starch Synthase III are two important factors responsible for the formation of the vitreous phenotype of QPM endosperms.
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Affiliation(s)
- Hao Wu
- Department of Biology, Baylor University, Waco, Texas, 76798, United States of America
| | - Kasi Clay
- Department of Biology, Baylor University, Waco, Texas, 76798, United States of America
| | - Stephanie S. Thompson
- Department of Biology, Baylor University, Waco, Texas, 76798, United States of America
| | - Tracie A. Hennen-Bierwagen
- Iowa State University, Department of Biochemistry, Biophysics, and Molecular Biology, Ames, Iowa, 50011, United States of America
| | - Bethany J. Andrews
- Texas A&M University, Department of Soil and Crop Sciences, College Station, Texas, 77843, United States of America
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, Texas, 76798, United States of America
| | - Bryan C. Gibbon
- Department of Biological Sciences, Florida A&M University, Tallahassee, Florida, 32307, United States of America
- * E-mail:
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Vidović M, Morina F, Milić S, Zechmann B, Albert A, Winkler JB, Veljović Jovanović S. Ultraviolet-B component of sunlight stimulates photosynthesis and flavonoid accumulation in variegated Plectranthus coleoides leaves depending on background light. Plant Cell Environ 2015; 38:968-79. [PMID: 25311561 DOI: 10.1111/pce.12471] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [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: 11/09/2013] [Revised: 09/26/2014] [Accepted: 10/06/2014] [Indexed: 05/07/2023]
Abstract
We used variegated Plectranthus coleoides as a model plant with the aim of clarifying whether the effects of realistic ultraviolet-B (UV-B) doses on phenolic metabolism in leaves are mediated by photosynthesis. Plants were exposed to UV-B radiation (0.90 W m(-2) ) combined with two photosynthetically active radiation (PAR) intensities [395 and 1350 μmol m(-2) s(-1) , low light (LL) and high light (HL)] for 9 d in sun simulators. Our study indicates that UV-B component of sunlight stimulates CO2 assimilation and stomatal conductance, depending on background light. UV-B-specific induction of apigenin and cyanidin glycosides was observed in both green and white tissues. However, all the other phenolic subclasses were up to four times more abundant in green leaf tissue. Caffeic and rosmarinic acids, catechin and epicatechin, which are endogenous peroxidase substrates, were depleted at HL in green tissue. This was correlated with increased peroxidase and ascorbate peroxidase activities and increased ascorbate content. The UV-B supplement to HL attenuated antioxidative metabolism and partly recovered the phenolic pool indicating stimulation of the phenylpropanoid pathway. In summary, we propose that ortho-dihydroxy phenolics are involved in antioxidative defence in chlorophyllous tissue upon light excess, while apigenin and cyanidin in white tissue have preferentially UV-screening function.
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Affiliation(s)
- Marija Vidović
- Institute for Multidisciplinary Research, University of Belgrade, Belgrade, 11000, Serbia
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Redkar A, Hoser R, Schilling L, Zechmann B, Krzymowska M, Walbot V, Doehlemann G. A Secreted Effector Protein of Ustilago maydis Guides Maize Leaf Cells to Form Tumors. Plant Cell 2015; 27:1332-51. [PMID: 25888589 PMCID: PMC4558682 DOI: 10.1105/tpc.114.131086] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 03/31/2015] [Indexed: 05/15/2023]
Abstract
The biotrophic smut fungus Ustilago maydis infects all aerial organs of maize (Zea mays) and induces tumors in the plant tissues. U. maydis deploys many effector proteins to manipulate its host. Previously, deletion analysis demonstrated that several effectors have important functions in inducing tumor expansion specifically in maize leaves. Here, we present the functional characterization of the effector See1 (Seedling efficient effector1). See1 is required for the reactivation of plant DNA synthesis, which is crucial for tumor progression in leaf cells. By contrast, See1 does not affect tumor formation in immature tassel floral tissues, where maize cell proliferation occurs independent of fungal infection. See1 interacts with a maize homolog of SGT1 (Suppressor of G2 allele of skp1), a factor acting in cell cycle progression in yeast (Saccharomyces cerevisiae) and an important component of plant and human innate immunity. See1 interferes with the MAPK-triggered phosphorylation of maize SGT1 at a monocot-specific phosphorylation site. We propose that See1 interferes with SGT1 activity, resulting in both modulation of immune responses and reactivation of DNA synthesis in leaf cells. This identifies See1 as a fungal effector that directly and specifically contributes to the formation of leaf tumors in maize.
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Affiliation(s)
- Amey Redkar
- Max Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, D-35043 Marburg, Germany
| | - Rafal Hoser
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Lena Schilling
- Max Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, D-35043 Marburg, Germany
| | - Bernd Zechmann
- Baylor University, Center for Microscopy and Imaging, Waco, Texas 76798
| | - Magdalena Krzymowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Virginia Walbot
- Department of Biology, Stanford University, Stanford, California 94305
| | - Gunther Doehlemann
- Max Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, D-35043 Marburg, Germany Botanical Institute and Cluster of Excellence on Plant Sciences, University of Cologne, 50674 Cologne, Germany
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Holzinger A, Kaplan F, Blaas K, Zechmann B, Komsic-Buchmann K, Becker B. Transcriptomics of desiccation tolerance in the streptophyte green alga Klebsormidium reveal a land plant-like defense reaction. PLoS One 2014; 9:e110630. [PMID: 25340847 PMCID: PMC4207709 DOI: 10.1371/journal.pone.0110630] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 09/15/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Water loss has significant effects on physiological performance and survival rates of algae. However, despite the prominent presence of aeroterrestrial algae in terrestrial habitats, hardly anything is known about the molecular events that allow aeroterrestrial algae to survive harsh environmental conditions. We analyzed the transcriptome and physiology of a strain of the alpine aeroterrestrial alga Klebsormidium crenulatum under control and strong desiccation-stress conditions. PRINCIPAL FINDINGS For comparison we first established a reference transcriptome. The high-coverage reference transcriptome includes about 24,183 sequences (1.5 million reads, 636 million bases). The reference transcriptome encodes for all major pathways (energy, carbohydrates, lipids, amino acids, sugars), nearly all deduced pathways are complete or missing only a few transcripts. Upon strong desiccation, more than 7000 transcripts showed changes in their expression levels. Most of the highest up-regulated transcripts do not show similarity to known viridiplant proteins, suggesting the existence of some genus- or species-specific responses to desiccation. In addition, we observed the up-regulation of many transcripts involved in desiccation tolerance in plants (e.g. proteins similar to those that are abundant in late embryogenesis (LEA), or proteins involved in early response to desiccation ERD), and enzymes involved in the biosynthesis of the raffinose family of oligosaccharides (RFO) known to act as osmolytes). Major physiological shifts are the up-regulation of transcripts for photosynthesis, energy production, and reactive oxygen species (ROS) metabolism, which is supported by elevated cellular glutathione content as revealed by immunoelectron microscopy as well as an increase in total antiradical power. However, the effective quantum yield of Photosystem II and CO2 fixation decreased sharply under the applied desiccation stress. In contrast, transcripts for cell integrative functions such as cell division, DNA replication, cofactor biosynthesis, and amino acid biosynthesis were down-regulated. SIGNIFICANCE This is the first study investigating the desiccation transcriptome of a streptophyte green alga. Our results indicate that the cellular response is similar to embryophytes, suggesting that embryophytes inherited a basic cellular desiccation tolerance from their streptophyte predecessors.
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Affiliation(s)
- Andreas Holzinger
- University of Innsbruck, Functional Plant Biology, Innsbruck, Austria
| | - Franziska Kaplan
- University of Innsbruck, Functional Plant Biology, Innsbruck, Austria
| | - Kathrin Blaas
- University of Innsbruck, Functional Plant Biology, Innsbruck, Austria
| | - Bernd Zechmann
- Baylor University, Center for Microscopy and Imaging, Waco, Texas, United States of America
| | | | - Burkhard Becker
- University of Cologne, Botanical Institute, Biocenter, Cologne, Germany
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Koffler BE, Luschin-Ebengreuth N, Stabentheiner E, Müller M, Zechmann B. Compartment specific response of antioxidants to drought stress in Arabidopsis. Plant Sci 2014; 227:133-44. [PMID: 25219315 PMCID: PMC4180016 DOI: 10.1016/j.plantsci.2014.08.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [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: 06/03/2014] [Revised: 08/01/2014] [Accepted: 08/03/2014] [Indexed: 05/18/2023]
Abstract
Compartment specific changes in ascorbate and glutathione contents were studied during drought stress in Arabidopsis thaliana Col-0 and in ascorbate and glutathione deficient mutants vtc2-1 and pad2-1, respectively, over a time period of 10 days. The results of this study revealed a strong decrease of glutathione contents in both mutants (up to 52% in mitochondria of pad2-1 and 40% in nuclei of vtc2-1) at early time points when drought stress was not yet measurable in leaves even though the soil showed a drop in relative water contents. These results indicate that glutathione is used at early time points to signal drought stress from roots to leaves. Such roles could not be confirmed for ascorbate which remained unchanged in most cell compartments until very late stages of drought. During advanced drought stress the strong depletion of ascorbate and glutathione in chloroplasts (up to 50% in Col-0 and vtc2-1) and peroxisomes (up to 56% in Col-0) could be correlated with a strong accumulation of H2O2. The strong increase of H2O2 and ascorbate in vacuoles (up to 111%) in wildtype plants indicates that ascorbate plays an important role for the detoxification of ROS in vacuoles during drought stress.
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Affiliation(s)
- Barbara Eva Koffler
- University of Graz, Institute of Plant Sciences, Schubertstrasse 51, 8010 Graz, Austria
| | | | - Edith Stabentheiner
- University of Graz, Institute of Plant Sciences, Schubertstrasse 51, 8010 Graz, Austria
| | - Maria Müller
- University of Graz, Institute of Plant Sciences, Schubertstrasse 51, 8010 Graz, Austria
| | - Bernd Zechmann
- Baylor University, Center for Microscopy and Imaging, One Bear Place #97046, Waco, TX 76798, USA.
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Koffler BE, Polanschütz L, Zechmann B. Higher sensitivity of pad2-1 and vtc2-1 mutants to cadmium is related to lower subcellular glutathione rather than ascorbate contents. Protoplasma 2014; 251:755-69. [PMID: 24281833 PMCID: PMC4059996 DOI: 10.1007/s00709-013-0576-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [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: 07/10/2013] [Accepted: 10/25/2013] [Indexed: 05/02/2023]
Abstract
Cadmium (Cd) interferes with ascorbate and glutathione metabolism as it induces the production of reactive oxygen species (ROS), binds to glutathione due to its high affinity to thiol groups, and induces the production of phytochelatins (PCs) which use glutathione as a precursor. In this study, changes in the compartment specific distribution of ascorbate and glutathione were monitored over a time period of 14 days in Cd-treated (50 and 100 μM) Arabidopsis Col-0 plants, and two mutant lines deficient in glutathione (pad2-1) and ascorbate (vtc2-1). Both mutants showed higher sensitivity to Cd than Col-0 plants. Strongly reduced compartment specific glutathione, rather than decreased ascorbate contents, could be correlated with the development of symptoms in these mutants suggesting that higher sensitivity to Cd is related to low glutathione contents rather than low ascorbate contents. On the subcellular level it became obvious that long-term treatment of wildtype plants with Cd induced the depletion of glutathione and ascorbate contents in all cell compartments except chloroplasts indicating an important protective role for antioxidants in chloroplasts against Cd. Additionally, we could observe an immediate decrease of glutathione and ascorbate in all cell compartments 12 h after Cd treatment indicating that glutathione and ascorbate are either withdrawn from or not redistributed into other organelles after their production in chloroplasts, cytosol (production centers for glutathione) and mitochondria (production center for ascorbate). The obtained data is discussed in respect to recently proposed stress models involving antioxidants in the protection of plants against environmental stress conditions.
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Affiliation(s)
- Barbara Eva Koffler
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, 8010 Graz, Austria
| | - Lisa Polanschütz
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, 8010 Graz, Austria
| | - Bernd Zechmann
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, 8010 Graz, Austria
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Hof A, Zechmann B, Schwammbach D, Hückelhoven R, Doehlemann G. Alternative cell death mechanisms determine epidermal resistance in incompatible barley-Ustilago interactions. Mol Plant Microbe Interact 2014; 27:403-414. [PMID: 24329174 DOI: 10.1094/mpmi-10-13-0317-r] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Programmed cell death is a key feature of epidermal plant immunity, which is particularly effective against biotrophic microbes that depend on living host tissue. The covered smut fungus Ustilago hordei establishes a compatible biotrophic interaction with its host plant barley. The maize smut U. maydis triggers a nonhost response in barley, which results in epidermal cell death. Similarly, Ustilago mutants being deleted for pep1, a gene encoding a secreted effector, are blocked upon host penetration. We studied the epidermal responses of barley to incompatible Ustilago strains. Molecular and cellular analyses were used to test the impact of Bax inhibitor-1 (BI-1), a suppressor of programmed cell death, on the barley nonhost resistance to U. maydis as well as Ustilago Δpep1 mutants. Overexpression of BI-1 resulted in partial break of barley nonhost resistance to U. maydis. By contrast, the epidermal cell death response triggered by pep1 deletion mutants was not impaired by BI-1. Hypersensitive-response-like cell death caused by U. maydis wild-type infection showed features of necrotic cell death, while Δpep1 mutant-induced host responses involved hallmarks of autophagy. Therefore, we propose that the mechanisms of epidermal cell death in response to different types of incompatible pathogens depend on spatial and temporal appearance of cell-death-triggering stimuli.
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Zellnig G, Pöckl MH, Möstl S, Zechmann B. Two and three dimensional characterization of Zucchini Yellow Mosaic Virus induced structural alterations in Cucurbita pepo L. plants. J Struct Biol 2014; 186:245-52. [PMID: 24631670 PMCID: PMC4013552 DOI: 10.1016/j.jsb.2014.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 02/26/2014] [Accepted: 03/06/2014] [Indexed: 11/06/2022]
Abstract
Infection of plants by Zucchini Yellow Mosaic Virus (ZYMV) induces severe ultrastructural changes. The aim of this study was to investigate ultrastructural changes during ZYMV-infection in Cucurbita pepo L. plants on the two and three dimensional (2D and 3D) level and to correlate these changes with the spread of ZYMV throughout the plant by transmission electron microscopy (TEM) and image analysis. This study revealed that after inoculation of the cotyledons ZYMV moved into roots [3 days post inoculation (dpi)], then moved upwards into the stem and apical meristem (5 dpi), then into the first true leaf (7 dpi) and could finally be found in all plant parts (9 dpi). ZYMV-infected cells contained viral inclusion bodies in the form of cylindrical inclusions (CIs). These CIs occurred in four different forms throughout the cytosol of roots and leaves: scrolls and pinwheels when cut transversely and long tubular structures and bundles of filaments when cut longitudinally. 3D reconstruction of ZYMV-infected cells containing scrolls revealed that they form long tubes throughout the cytosol. The majority has a preferred orientation and an average length and width of 3 μm and 120 nm, respectively. Image analysis revealed an increased size of cells and vacuoles (107% and 447%, respectively) in younger ZYMV-infected leaves leading to a similar ratio of cytoplasm to vacuole (about 1:1) in older and younger ZYMV-infected leaves which indicates advanced cell growth in younger tissues. The collected data advances the current knowledge about ZYMV-induced ultrastructural changes in Cucurbita pepo.
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Affiliation(s)
- Günther Zellnig
- University of Graz, Institute of Plant Physiology, Schubertstrasse 51, A-8010 Graz, Austria
| | - Michael Herbert Pöckl
- University of Graz, Institute of Plant Physiology, Schubertstrasse 51, A-8010 Graz, Austria
| | - Stefan Möstl
- University of Graz, Institute of Plant Physiology, Schubertstrasse 51, A-8010 Graz, Austria
| | - Bernd Zechmann
- University of Graz, Institute of Plant Physiology, Schubertstrasse 51, A-8010 Graz, Austria.
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Zechmann B. Compartment-specific importance of glutathione during abiotic and biotic stress. Front Plant Sci 2014; 5:566. [PMID: 25368627 PMCID: PMC4202713 DOI: 10.3389/fpls.2014.00566] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 10/01/2014] [Indexed: 05/19/2023]
Abstract
The tripeptide thiol glutathione (γ-L-glutamyl-L-cysteinyl-glycine) is the most important sulfur containing antioxidant in plants and essential for plant defense against abiotic and biotic stress conditions. It is involved in the detoxification of reactive oxygen species (ROS), redox signaling, the modulation of defense gene expression, and the regulation of enzymatic activities. Even though changes in glutathione contents are well documented in plants and its roles in plant defense are well established, still too little is known about its compartment-specific importance during abiotic and biotic stress conditions. Due to technical advances in the visualization of glutathione and the redox state through microscopical methods some progress was made in the last few years in studying the importance of subcellular glutathione contents during stress conditions in plants. This review summarizes the data available on compartment-specific importance of glutathione in the protection against abiotic and biotic stress conditions such as high light stress, exposure to cadmium, drought, and pathogen attack (Pseudomonas, Botrytis, tobacco mosaic virus). The data will be discussed in connection with the subcellular accumulation of ROS during these conditions and glutathione synthesis which are both highly compartment specific (e.g., glutathione synthesis takes place in chloroplasts and the cytosol). Thus this review will reveal the compartment-specific importance of glutathione during abiotic and biotic stress conditions.
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Affiliation(s)
- Bernd Zechmann
- *Correspondence: Bernd Zechmann, Center for Microscopy and Imaging, Baylor University, One Bear Place #97046, Waco, TX 76798, USA e-mail:
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Kocsy G, Tari I, Vanková R, Zechmann B, Gulyás Z, Poór P, Galiba G. Redox control of plant growth and development. Plant Sci 2013; 211:77-91. [PMID: 23987814 DOI: 10.1016/j.plantsci.2013.07.004] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 06/27/2013] [Accepted: 07/09/2013] [Indexed: 05/08/2023]
Abstract
Redox changes determined by genetic and environmental factors display well-organized interactions in the control of plant growth and development. Diurnal and seasonal changes in the environmental conditions are important for the normal course of these physiological processes and, similarly to their mild irregular alterations, for stress adaptation. However, fast or large-scale environmental changes may lead to damage or death of sensitive plants. The spatial and temporal redox changes influence growth and development due to the reprogramming of metabolism. In this process reactive oxygen and nitrogen species and antioxidants are involved as components of signalling networks. The control of growth, development and flowering by reactive oxygen and nitrogen species and antioxidants in interaction with hormones at organ, tissue, cellular and subcellular level will be discussed in the present review. Unsolved problems of the field, among others the need for identification of new components and interactions in the redox regulatory network at various organization levels using systems biology approaches will be also indicated.
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Affiliation(s)
- Gábor Kocsy
- Agricultural Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Brunszvik u. 2., Martonvásár, Hungary.
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Heyneke E, Luschin-Ebengreuth N, Krajcer I, Wolkinger V, Müller M, Zechmann B. Dynamic compartment specific changes in glutathione and ascorbate levels in Arabidopsis plants exposed to different light intensities. BMC Plant Biol 2013; 13:104. [PMID: 23865417 PMCID: PMC3728233 DOI: 10.1186/1471-2229-13-104] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 07/16/2013] [Indexed: 05/03/2023]
Abstract
BACKGROUND Excess light conditions induce the generation of reactive oxygen species (ROS) directly in the chloroplasts but also cause an accumulation and production of ROS in peroxisomes, cytosol and vacuoles. Antioxidants such as ascorbate and glutathione occur in all cell compartments where they detoxify ROS. In this study compartment specific changes in antioxidant levels and related enzymes were monitored among Arabidopsis wildtype plants and ascorbate and glutathione deficient mutants (vtc2-1 and pad2-1, respectively) exposed to different light intensities (50, 150 which was considered as control condition, 300, 700 and 1,500 μmol m(-2) s(-1)) for 4 h and 14 d. RESULTS The results revealed that wildtype plants reacted to short term exposure to excess light conditions with the accumulation of ascorbate and glutathione in chloroplasts, peroxisomes and the cytosol and an increased activity of catalase in the leaves. Long term exposure led to an accumulation of ascorbate and glutathione mainly in chloroplasts. In wildtype plants an accumulation of ascorbate and hydrogen peroxide (H2O2) could be observed in vacuoles when exposed to high light conditions. The pad2-1 mutant reacted to long term excess light exposure with an accumulation of ascorbate in peroxisomes whereas the vtc2-1 mutant reacted with an accumulation of glutathione in the chloroplasts (relative to the wildtype) and nuclei during long term high light conditions indicating an important role of these antioxidants in these cell compartments for the protection of the mutants against high light stress. CONCLUSION The results obtained in this study demonstrate that the accumulation of ascorbate and glutathione in chloroplasts, peroxisomes and the cytosol is an important reaction of plants to short term high light stress. The accumulation of ascorbate and H2O2 along the tonoplast and in vacuoles during these conditions indicates an important route for H2O2 detoxification under these conditions.
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Affiliation(s)
- Elmien Heyneke
- Department of Lothar Willmitzer, Max-Planck-Institute of Molecular Plant Physiology, Golm, 14476, Germany
| | - Nora Luschin-Ebengreuth
- Institute for Electron Microscopy and Fine Structure Research, Graz University of Technology, Steyrergasse 17, Graz, 8010, Austria
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
| | - Iztok Krajcer
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
| | - Volker Wolkinger
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
| | - Maria Müller
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
| | - Bernd Zechmann
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
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Simon UK, Polanschütz LM, Koffler BE, Zechmann B. High resolution imaging of temporal and spatial changes of subcellular ascorbate, glutathione and H₂O₂ distribution during Botrytis cinerea infection in Arabidopsis. PLoS One 2013; 8:e65811. [PMID: 23755284 PMCID: PMC3673919 DOI: 10.1371/journal.pone.0065811] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 05/03/2013] [Indexed: 11/23/2022] Open
Abstract
In order to study the mechanisms behind the infection process of the necrotrophic fungus Botrytis cinerea, the subcellular distribution of hydrogen peroxide (H₂O₂) was monitored over a time frame of 96 h post inoculation (hpi) in Arabidopsis thaliana Col-0 leaves at the inoculation site (IS) and the area around the IS which was defined as area adjacent to the inoculation site (AIS). H₂O₂ accumulation was correlated with changes in the compartment-specific distribution of ascorbate and glutathione and chloroplast fine structure. This study revealed that the severe breakdown of the antioxidative system, indicated by a drop in ascorbate and glutathione contents at the IS at later stages of infection correlated with an accumulation of H₂O₂ in chloroplasts, mitochondria, cell walls, nuclei and the cytosol which resulted in the development of chlorosis and cell death, eventually visible as tissue necrosis. A steady increase of glutathione contents in most cell compartments within infected tissues (up to 600% in chloroplasts at 96 hpi) correlated with an accumulation of H₂O₂ in chloroplasts, mitochondria and cell walls at the AIS indicating that high glutathione levels could not prevent the accumulation of reactive oxygen species (ROS) which resulted in chlorosis. Summing up, this study reveals the intracellular sequence of events during Botrytis cinerea infection and shows that the breakdown of the antioxidative system correlated with the accumulation of H₂O₂ in the host cells. This resulted in the degeneration of the leaf indicated by severe changes in the number and ultrastructure of chloroplasts (e.g. decrease of chloroplast number, decrease of starch and thylakoid contents, increase of plastoglobuli size), chlorosis and necrosis of the leaves.
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Affiliation(s)
- Uwe K. Simon
- Institute of Plant Sciences, University of Graz, Graz, Austria
| | | | | | - Bernd Zechmann
- Institute of Plant Sciences, University of Graz, Graz, Austria
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Han Y, Chaouch S, Mhamdi A, Queval G, Zechmann B, Noctor G. Functional analysis of Arabidopsis mutants points to novel roles for glutathione in coupling H(2)O(2) to activation of salicylic acid accumulation and signaling. Antioxid Redox Signal 2013; 18:2106-21. [PMID: 23148658 PMCID: PMC3629853 DOI: 10.1089/ars.2012.5052] [Citation(s) in RCA: 162] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
AIMS Through its interaction with H(2)O(2), glutathione is a candidate for transmission of signals in plant responses to pathogens, but identification of signaling roles is complicated by its antioxidant function. Using a genetic approach based on a conditional catalase-deficient Arabidopsis mutant, cat2, this study aimed at establishing whether GSH plays an important functional role in the transmission of signals downstream of H(2)O(2). RESULTS Introducing the cad2 or allelic mutations in the glutathione synthesis pathway into cat2 blocked H(2)O(2)-triggered GSH oxidation and accumulation. While no effects on NADP(H) or ascorbate were observed, and H(2)O(2)-induced decreases in growth were maintained, blocking GSH modulation antagonized salicylic acid (SA) accumulation and SA-dependent responses. Other novel double and triple mutants were produced and compared with cat2 cad2 at the levels of phenotype, expression of marker genes, nontargeted metabolite profiling, accumulation of SA, and bacterial resistance. Most of the effects of the cad2 mutation on H(2)O(2)-triggered responses were distinct from those produced by mutations for GLUTATHIONE REDUCTASE1 (GR1) or NONEXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1), and were linked to compromised induction of ISOCHORISMATE SYNTHASE1 (ICS1) and ICS1-dependent SA accumulation. INNOVATION A novel genetic approach was used in which GSH content or antioxidative capacity was independently modified in an H(2)O(2) signaling background. Analysis of new double and triple mutants allowed us to infer previously undescribed regulatory roles for GSH. CONCLUSION In parallel to its antioxidant role, GSH acts independently of NPR1 to allow increased intracellular H(2)O(2) to activate SA signaling, a key defense response in plants.
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Affiliation(s)
- Yi Han
- Institut de Biologie des Plantes, UMR CNRS 8618, Université de Paris Sud, Orsay Cedex, France
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47
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Han Y, Chaouch S, Mhamdi A, Queval G, Zechmann B, Noctor G. Functional analysis of Arabidopsis mutants points to novel roles for glutathione in coupling H(2)O(2) to activation of salicylic acid accumulation and signaling. Antioxid Redox Signal 2013. [PMID: 23148658 DOI: 10.1089/ars.20125052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/17/2023]
Abstract
AIMS Through its interaction with H(2)O(2), glutathione is a candidate for transmission of signals in plant responses to pathogens, but identification of signaling roles is complicated by its antioxidant function. Using a genetic approach based on a conditional catalase-deficient Arabidopsis mutant, cat2, this study aimed at establishing whether GSH plays an important functional role in the transmission of signals downstream of H(2)O(2). RESULTS Introducing the cad2 or allelic mutations in the glutathione synthesis pathway into cat2 blocked H(2)O(2)-triggered GSH oxidation and accumulation. While no effects on NADP(H) or ascorbate were observed, and H(2)O(2)-induced decreases in growth were maintained, blocking GSH modulation antagonized salicylic acid (SA) accumulation and SA-dependent responses. Other novel double and triple mutants were produced and compared with cat2 cad2 at the levels of phenotype, expression of marker genes, nontargeted metabolite profiling, accumulation of SA, and bacterial resistance. Most of the effects of the cad2 mutation on H(2)O(2)-triggered responses were distinct from those produced by mutations for GLUTATHIONE REDUCTASE1 (GR1) or NONEXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1), and were linked to compromised induction of ISOCHORISMATE SYNTHASE1 (ICS1) and ICS1-dependent SA accumulation. INNOVATION A novel genetic approach was used in which GSH content or antioxidative capacity was independently modified in an H(2)O(2) signaling background. Analysis of new double and triple mutants allowed us to infer previously undescribed regulatory roles for GSH. CONCLUSION In parallel to its antioxidant role, GSH acts independently of NPR1 to allow increased intracellular H(2)O(2) to activate SA signaling, a key defense response in plants.
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Affiliation(s)
- Yi Han
- Institut de Biologie des Plantes, UMR CNRS 8618, Université de Paris Sud, Orsay Cedex, France
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Zellnig G, Möstl S, Zechmann B. Rapid immunohistochemical diagnosis of tobacco mosaic virus disease by microwave-assisted plant sample preparation. Microscopy (Oxf) 2013; 62:547-53. [PMID: 23580761 PMCID: PMC4030761 DOI: 10.1093/jmicro/dft022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 03/20/2013] [Indexed: 11/12/2022] Open
Abstract
Immunoelectron microscopy is a powerful method to diagnose viral diseases and to study the distribution of the viral agent within plant cells and tissues. Nevertheless, current protocols for the immunological detection of viral diseases with transmission electron microscopy (TEM) in plants take between 3 and 6 days and are therefore not suited for rapid diagnosis of virus diseases in plants. In this study, we describe a method that allows rapid cytohistochemical detection of tobacco mosaic virus (TMV) in leaves of tobacco plants. With the help of microwave irradiation, sample preparation of the leaves was reduced to 90 min. After sample sectioning, virus particles were stained on the sections by immunogold labelling of the viral coat protein, which took 100 min. After investigation with the TEM, a clear visualization of TMV in tobacco cells was achieved altogether in about half a day. Comparison of gold particle density by image analysis revealed that samples prepared with the help of microwave irradiation yielded significantly higher gold particle density as samples prepared conventionally at room temperature. This study clearly demonstrates that microwave-assisted plant sample preparation in combination with cytohistochemical localization of viral coat protein is well suited for rapid diagnosis of plant virus diseases in altogether about half a day by TEM.
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Affiliation(s)
| | | | - Bernd Zechmann
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, 8010 Graz, Austria
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Koffler BE, Bloem E, Zellnig G, Zechmann B. High resolution imaging of subcellular glutathione concentrations by quantitative immunoelectron microscopy in different leaf areas of Arabidopsis. Micron 2012; 45:119-28. [PMID: 23265941 PMCID: PMC3553553 DOI: 10.1016/j.micron.2012.11.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 11/23/2012] [Accepted: 11/24/2012] [Indexed: 01/06/2023]
Abstract
Glutathione is an important antioxidant and redox buffer in plants. It fulfills many important roles during plant development, defense and is essential for plant metabolism. Even though the compartment specific roles of glutathione during abiotic and biotic stress situations have been studied in detail there is still great lack of knowledge about subcellular glutathione concentrations within the different leaf areas at different stages of development. In this study a method is described that allows the calculation of compartment specific glutathione concentrations in all cell compartments simultaneously in one experiment by using quantitative immunogold electron microscopy combined with biochemical methods in different leaf areas of Arabidopsis thaliana Col-0 (center of the leaf, leaf apex, leaf base and leaf edge). The volume of subcellular compartments in the mesophyll of Arabidopsis was found to be similar to other plants. Vacuoles covered the largest volume within a mesophyll cell and increased with leaf age (up to 80% in the leaf apex of older leaves). Behind vacuoles, chloroplasts covered the second largest volume (up to 20% in the leaf edge of the younger leaves) followed by nuclei (up to 2.3% in the leaf edge of the younger leaves), mitochondria (up to 1.6% in the leaf apex of the younger leaves), and peroxisomes (up to 0.3% in the leaf apex of the younger leaves). These values together with volumes of the mesophyll determined by stereological methods from light and electron micrographs and global glutathione contents measured with biochemical methods enabled the determination of subcellular glutathione contents in mM. Even though biochemical investigations did not reveal differences in global glutathione contents, compartment specific differences could be observed in some cell compartments within the different leaf areas. Highest concentrations of glutathione were always found in mitochondria, where values in a range between 8.7 mM (in the apex of younger leaves) and 15.1 mM (in the apex of older leaves) were found. The second highest amount of glutathione was found in nuclei (between 5.5 mM and 9.7 mM in the base and the center of younger leaves, respectively) followed by peroxisomes (between 2.6 mM in the edge of younger leaves and 4.8 mM in the base of older leaves, respectively) and the cytosol (2.8 mM in the edge of younger and 4.5 mM in the center of older leaves, respectively). Chloroplasts contained rather low amounts of glutathione (between 1 mM and 1.4 mM). Vacuoles had the lowest concentrations of glutathione (0.01 mM and 0.14 mM) but showed large differences between the different leaf areas. Clear differences in glutathione contents between the different leaf areas could only be found in vacuoles and mitochondria revealing that glutathione in the later cell organelle accumulated with leaf age to concentrations of up to 15 mM and that concentrations of glutathione in vacuoles are quite low in comparison to the other cell compartments.
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Affiliation(s)
- Barbara E Koffler
- University of Graz, Institute of Plant Sciences, Schubertstrasse 51, A-8010 Graz, Austria.
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50
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Király L, Künstler A, Höller K, Fattinger M, Juhász C, Müller M, Gullner G, Zechmann B. Sulfate supply influences compartment specific glutathione metabolism and confers enhanced resistance to Tobacco mosaic virus during a hypersensitive response. Plant Physiol Biochem 2012; 59:44-54. [PMID: 22122784 PMCID: PMC3458214 DOI: 10.1016/j.plaphy.2011.10.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 10/28/2011] [Indexed: 05/19/2023]
Abstract
Sufficient sulfate supply has been linked to the development of sulfur induced resistance or sulfur enhanced defense (SIR/SED) in plants. In this study we investigated the effects of sulfate (S) supply on the response of genetically resistant tobacco (Nicotiana tabacum cv. Samsun NN) to Tobacco mosaic virus (TMV). Plants grown with sufficient sulfate (+S plants) developed significantly less necrotic lesions during a hypersensitive response (HR) when compared to plants grown without sulfate (-S plants). In +S plants reduced TMV accumulation was evident on the level of viral RNA. Enhanced virus resistance correlated with elevated levels of cysteine and glutathione and early induction of a Tau class glutathione S-transferase and a salicylic acid-binding catalase gene. These data indicate that the elevated antioxidant capacity of +S plants was able to reduce the effects of HR, leading to enhanced virus resistance. Expression of pathogenesis-related genes was also markedly up-regulated in +S plants after TMV-inoculation. On the subcellular level, comparison of TMV-inoculated +S and -S plants revealed that +S plants contained 55-132 % higher glutathione levels in mitochondria, chloroplasts, nuclei, peroxisomes and the cytosol than -S plants. Interestingly, mitochondria were the only organelles where TMV-inoculation resulted in a decrease of glutathione levels when compared to mock-inoculated plants. This was particularly obvious in -S plants, where the development of necrotic lesions was more pronounced. In summary, the overall higher antioxidative capacity and elevated activation of defense genes in +S plants indicate that sufficient sulfate supply enhances a preexisting plant defense reaction resulting in reduced symptom development and virus accumulation.
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Key Words
- cysteine
- glutathione
- nicotiana tabacum
- salicylic acid
- sulfur induced resistance
- tobacco mosaic virus
- apr, adenosine 5′-phosphosulfate reductase
- bsa, bovine serum albumin
- catsab, salicylic acid-binding catalase
- cp, coat protein
- dpi, days post inoculation
- gsh1, γ-glutamyl cysteine synthetase
- gsh2, glutathione synthetase
- gsttau1, tau class glutathione s-transferase
- hr, hypersensitive response
- pbs, phosphate buffered saline
- pcd, programmed cell death
- ros, reactive oxygen species
- s, sulfate
- sir, sulfur induced resistance
- sed, sulfur enhanced defense
- tmv, tobacco mosaic virus
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Affiliation(s)
- Lóránt Király
- Plant Protection Institute, Hungarian Academy of Sciences, P.O. Box 102, 1525 Budapest, Hungary
| | - András Künstler
- Plant Protection Institute, Hungarian Academy of Sciences, P.O. Box 102, 1525 Budapest, Hungary
| | - Kerstin Höller
- University of Graz, Institute of Plant Sciences, Schubertstrasse 51, 8010 Graz, Austria
| | - Maria Fattinger
- University of Graz, Institute of Plant Sciences, Schubertstrasse 51, 8010 Graz, Austria
| | - Csilla Juhász
- Plant Protection Institute, Hungarian Academy of Sciences, P.O. Box 102, 1525 Budapest, Hungary
| | - Maria Müller
- University of Graz, Institute of Plant Sciences, Schubertstrasse 51, 8010 Graz, Austria
| | - Gábor Gullner
- Plant Protection Institute, Hungarian Academy of Sciences, P.O. Box 102, 1525 Budapest, Hungary
| | - Bernd Zechmann
- University of Graz, Institute of Plant Sciences, Schubertstrasse 51, 8010 Graz, Austria
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