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Pao SH, Tsai PY, Peng CI, Chen PJ, Tsai CC, Yang EC, Shih MC, Chen J, Yang JY, Chesson P, Sheue CR. Lamelloplasts and minichloroplasts in Begoniaceae: iridescence and photosynthetic functioning. J Plant Res 2018; 131:655-670. [PMID: 29500749 DOI: 10.1007/s10265-018-1020-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [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: 07/03/2017] [Accepted: 02/11/2018] [Indexed: 06/08/2023]
Abstract
Iridoplasts (modified plastids in adaxial epidermal cells) reported from Begonia were originally hypothesized to cause iridescence, which was broadly accepted for decades. However, several species of Begonia with iridoplasts are not iridescent causing confusion. Here chloroplast ultrastructure was observed in 40 taxa of Begoniaceae to explore the phenomenon of iridescence. However, 22 Begonias and Hillebrandia were found to have iridoplasts, but only nine display visually iridescent blue to blue-green leaves. Unexpectedly, a new type of plastid, a 'minichloroplast,' was found in the abaxial epidermal cells of all taxa, but was present in adaxial epidermal cells only if iridoplasts were absent. Comparative ultrastructural study of iridoplasts and a shading experiment of selected taxa show that a taxon with iridoplasts does not inevitably have visual iridescence, but iridescence is greatly affected by the spacing between thylakoid lamellae (stoma spacing). Thus, we propose instead the name 'lamelloplast' for plastids filled entirely with regular lamellae to avoid prejudging their function. To evaluate photosynthetic performance, chlorophyll fluorescence (F v /F m ) was measured separately from the chloroplasts in the adaxial epidermis and lower leaf tissues by using leaf dermal peels. Lamelloplasts and minichloroplasts have much lower photosynthetic efficiency than mesophyll chloroplasts. Nevertheless, photosynthetic proteins (psbA protein of PSII, RuBisCo and ATPase) were detected in both plastids as well as mesophyll chloroplasts in an immunogold labeling. Spectrometry revealed additional blue to blue-green peaks in visually iridescent leaves. Micro-spectrometry detected a blue peak from single blue spots in adaxial epidermal cells confirming that the color is derived from lamelloplasts. Presence of lamelloplasts or minichloroplasts is species specific and exclusive. High prevalence of lamelloplasts in Begoniaceae, including the basal clade Hillebrandia, highlights a unique evolutionary development. These new findings clarify the association between iridescence and lamelloplasts, and with implications for new directions in the study of plastid morphogenesis.
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Affiliation(s)
- Shang-Hung Pao
- Department of Life Sciences and Center of Global Change Biology, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung, 402, Taiwan
| | - Ping-Yun Tsai
- Department of Life Sciences and Center of Global Change Biology, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung, 402, Taiwan
| | - Ching-I Peng
- Biodiversity Research Center, Academia Sinica, 128, Sec. 2, Academia Rd., Taipei, 115, Taiwan
| | - Pei-Ju Chen
- Department of Entomology, National Taiwan University, 1, Sec. 4, Roosevelt Rd., Taipei, 106, Taiwan
- Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa, 240-0193, Japan
| | - Chi-Chu Tsai
- Kaohsiung District Agricultural Research and Extension Station, 2-6 Dehe Rd., Changjhih, 908, Pingtung County, Taiwan
| | - En-Cheng Yang
- Department of Entomology, National Taiwan University, 1, Sec. 4, Roosevelt Rd., Taipei, 106, Taiwan
| | - Ming-Chih Shih
- Department of Physics, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung, 402, Taiwan
- Research Center for Sustainable Energy and Nanotechnology, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung, 402, Taiwan
| | - Jiannyeu Chen
- Department of Physics, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung, 402, Taiwan
- Research Center for Sustainable Energy and Nanotechnology, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung, 402, Taiwan
| | - Jun-Yi Yang
- Institute of Biochemistry, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung, 402, Taiwan
| | - Peter Chesson
- Department of Life Sciences and Center of Global Change Biology, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung, 402, Taiwan
- Department of Ecology and Evolutionary Biology, The University of Arizona, Tucson, AZ, 85721, USA
| | - Chiou-Rong Sheue
- Department of Life Sciences and Center of Global Change Biology, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung, 402, Taiwan.
- Department of Ecology and Evolutionary Biology, The University of Arizona, Tucson, AZ, 85721, USA.
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Cano-Garrido O, Garcia-Fruitós E, Villaverde A, Sánchez-Chardi A. Improving Biomaterials Imaging for Nanotechnology: Rapid Methods for Protein Localization at Ultrastructural Level. Biotechnol J 2018; 13:e1700388. [PMID: 29271611 DOI: 10.1002/biot.201700388] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 12/07/2017] [Indexed: 11/06/2022]
Abstract
The preparation of biological samples for electron microscopy is material- and time-consuming because it is often based on long protocols that also may produce artifacts. Protein labeling for transmission electron microscopy (TEM) is such an example, taking several days. However, for protein-based nanotechnology, high resolution imaging techniques are unique and crucial tools for studying the spatial distribution of these molecules, either alone or as components of biomaterials. In this paper, we tested two new short methods of immunolocalization for TEM, and compared them with a standard protocol in qualitative and quantitative approaches by using four protein-based nanoparticles. We reported a significant increase of labeling per area of nanoparticle in both new methodologies (H = 19.811; p < 0.001) with all the model antigens tested: GFP (H = 22.115; p < 0.001), MMP-2 (H = 19.579; p < 0.001), MMP-9 (H = 7.567; p < 0.023), and IFN-γ (H = 62.110; p < 0.001). We also found that the most suitable protocol for labeling depends on the nanoparticle's tendency to aggregate. Moreover, the shorter methods reduce artifacts, time (by 30%), residues, and reagents hindering, losing, or altering antigens, and obtaining a significant increase of protein localization (of about 200%). Overall, this study makes a step forward in the development of optimized protocols for the nanoscale localization of peptides and proteins within new biomaterials.
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Affiliation(s)
- Olivia Cano-Garrido
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain.,Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain.,CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN)
| | - Elena Garcia-Fruitós
- Departament de Producció de Remugants, Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Caldes de Montbui 08140, Spain
| | - Antonio Villaverde
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain.,Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain.,CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN)
| | - Alejandro Sánchez-Chardi
- Servei de Microscòpia, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona 08320, Spain
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Krasensky J, Broyart C, Rabanal FA, Jonak C. The redox-sensitive chloroplast trehalose-6-phosphate phosphatase AtTPPD regulates salt stress tolerance. Antioxid Redox Signal 2014; 21:1289-304. [PMID: 24800789 PMCID: PMC4158992 DOI: 10.1089/ars.2013.5693] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [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: 11/12/2022]
Abstract
AIMS High salinity stress impairs plant growth and development. Trehalose metabolism has been implicated in sugar signaling, and enhanced trehalose metabolism can positively regulate abiotic stress tolerance. However, the molecular mechanism(s) of the stress-related trehalose pathway and the role of individual trehalose biosynthetic enzymes for stress tolerance remain unclear. RESULTS Trehalose-6-phosphate phosphatase (TPP) catalyzes the final step of trehalose metabolism. Investigating the subcellular localization of the Arabidopsis thaliana TPP family members, we identified AtTPPD as a chloroplast-localized enzyme. Plants deficient in AtTPPD were hypersensitive, whereas plants overexpressing AtTPPD were more tolerant to high salinity stress. Elevated stress tolerance of AtTPPD overexpressors correlated with high starch levels and increased accumulation of soluble sugars, suggesting a role for AtTPPD in regulating sugar metabolism under salinity conditions. Biochemical analyses indicate that AtTPPD is a target of post-translational redox regulation and can be reversibly inactivated by oxidizing conditions. Two cysteine residues were identified as the redox-sensitive sites. Structural and mutation analyses suggest that the formation of an intramolecular disulfide bridge regulates AtTPPD activity. INNOVATION The activity of different AtTPP isoforms, located in the cytosol, nucleus, and chloroplasts, can be redox regulated, suggesting that the trehalose metabolism might relay the redox status of different cellular compartments to regulate diverse biological processes such as stress responses. CONCLUSION The evolutionary conservation of the two redox regulatory cysteine residues of TPPs in spermatophytes indicates that redox regulation of TPPs might be a common mechanism enabling plants to rapidly adjust trehalose metabolism to the prevailing environmental and developmental conditions.
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Affiliation(s)
- Julia Krasensky
- GMI-Gregor Mendel Institute of Molecular Plant Biology , Austrian Academy of Sciences, Vienna, Austria
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Vandesteene L, Ramon M, Le Roy K, Van Dijck P, Rolland F. A single active trehalose-6-P synthase (TPS) and a family of putative regulatory TPS-like proteins in Arabidopsis. Mol Plant 2010; 3:406-19. [PMID: 20100798 DOI: 10.1093/mp/ssp114] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Higher plants typically do not produce trehalose in large amounts, but their genome sequences reveal large families of putative trehalose metabolism enzymes. An important regulatory role in plant growth and development is also emerging for the metabolic intermediate trehalose-6-P (T6P). Here, we present an update on Arabidopsis trehalose metabolism and a resource for further detailed analyses. In addition, we provide evidence that Arabidopsis encodes a single trehalose-6-P synthase (TPS) next to a family of catalytically inactive TPS-like proteins that might fulfill specific regulatory functions in actively growing tissues.
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Affiliation(s)
- Lies Vandesteene
- Laboratory of Functional Biology, Plant Metabolic Signaling Group, Institute of Botany and Microbiology, KU Leuven, Kasteelpark Arenberg 31-bus 2438, B-3001 Heverlee, Belgium
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