1
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Wang Y, Wang M, Zhang Y, Peng L, Dai D, Zhang F, Zhang J. Efficient control of root-knot nematodes by expressing Bt nematicidal proteins in root leucoplasts. MOLECULAR PLANT 2024:S1674-2052(24)00259-4. [PMID: 39148293 DOI: 10.1016/j.molp.2024.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 06/12/2024] [Accepted: 08/08/2024] [Indexed: 08/17/2024]
Abstract
Root-knot nematodes (RKNs) are plant pests that infect the roots of host plants. Bacillus thuringiensis (Bt) nematicidal proteins exhibited toxicity to nematodes. However, the application of nematicidal proteins for plant protection is hampered by the lack of effective delivery systems in transgenic plants. In this study, we discovered the accumulation of leucoplasts (root plastids) in galls and RKN-induced giant cells. RKN infection causes the degradation of leucoplasts into small vesicle-like structures, which are responsible for delivering proteins to RKNs, as observed through confocal microscopy and immunoelectron microscopy. We showed that different-sized proteins from leucoplasts could be taken up by Meloidogyne incognita female. To further explore the potential applications of leucoplasts, we introduced the Bt crystal protein Cry5Ba2 into tobacco and tomato leucoplasts by fusing it with a transit peptide. The transgenic plants showed significant resistance to RKNs. Intriguingly, RKN females preferentially took up Cry5Ba2 protein when delivered through plastids rather than the cytosol. The decrease in progeny was positively correlated with the delivery efficiency of the nematicidal protein. In conclusion, this study offers new insights into the feeding behavior of RKNs and their ability to ingest leucoplast proteins, and demonstrates that root leucoplasts can be used for delivering nematicidal proteins, thereby offering a promising approach for nematode control.
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Affiliation(s)
- Yong Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Mengnan Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Yali Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Longwei Peng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Dadong Dai
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Fengjuan Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, School of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Jiang Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, School of Life Sciences, Hubei University, Wuhan 430062, China; Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518000, China.
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2
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Jung S, Woo J, Park E. Talk to your neighbors in an emergency: Stromule-mediated chloroplast-nucleus communication in plant immunity. CURRENT OPINION IN PLANT BIOLOGY 2024; 79:102529. [PMID: 38604000 DOI: 10.1016/j.pbi.2024.102529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 03/08/2024] [Accepted: 03/19/2024] [Indexed: 04/13/2024]
Abstract
Hypersensitive response-programmed cell death (HR-PCD) is a response mounted by plants to defend themselves against pathogens. Communication between the chloroplast and the nucleus is critical for the progression of HR-PCD. Tubular protrusions of chloroplasts, known as stromules, are tightly associated with the HR-PCD progression. There is emerging evidence that signaling molecules originating from chloroplasts are transferred to the nucleus through stromules. The translocation of signaling molecules from the chloroplast to the nucleus might trigger defense responses, including transcriptional reprogramming. In this review, we discuss the possible functions of stromules in the rapid transfer of signaling molecules in the chloroplast-nucleus communication.
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Affiliation(s)
- Seungmee Jung
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
| | - Jongchan Woo
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
| | - Eunsook Park
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA.
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3
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Mueller-Schuessele SJ, Leterme S, Michaud M. Plastid Transient and Stable Interactions with Other Cell Compartments. Methods Mol Biol 2024; 2776:107-134. [PMID: 38502500 DOI: 10.1007/978-1-0716-3726-5_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
Plastids are organelles delineated by two envelopes playing important roles in different cellular processes such as energy production or lipid biosynthesis. To regulate their biogenesis and their function, plastids have to communicate with other cellular compartments. This communication can be mediated by metabolites, signaling molecules, and by the establishment of direct contacts between the plastid envelope and other organelles such as the endoplasmic reticulum, mitochondria, peroxisomes, plasma membrane, and the nucleus. These interactions are highly dynamic and respond to different biotic and abiotic stresses. However, the mechanisms involved in the formation of plastid-organelle contact sites and their functions are still far from being understood. In this chapter, we summarize our current knowledge about plastid contact sites and their role in the regulation of plastid biogenesis and function.
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Affiliation(s)
| | - Sébastien Leterme
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS, CEA, INRAE, Univ. Grenoble Alpes, IRIG, CEA Grenoble, Grenoble, France
| | - Morgane Michaud
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS, CEA, INRAE, Univ. Grenoble Alpes, IRIG, CEA Grenoble, Grenoble, France.
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4
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Kumar V, Wegener M, Knieper M, Kaya A, Viehhauser A, Dietz KJ. Strategies of Molecular Signal Integration for Optimized Plant Acclimation to Stress Combinations. Methods Mol Biol 2024; 2832:3-29. [PMID: 38869784 DOI: 10.1007/978-1-0716-3973-3_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
Plant growth and survival in their natural environment require versatile mitigation of diverse threats. The task is especially challenging due to the largely unpredictable interaction of countless abiotic and biotic factors. To resist an unfavorable environment, plants have evolved diverse sensing, signaling, and adaptive molecular mechanisms. Recent stress studies have identified molecular elements like secondary messengers (ROS, Ca2+, etc.), hormones (ABA, JA, etc.), and signaling proteins (SnRK, MAPK, etc.). However, major gaps remain in understanding the interaction between these pathways, and in particular under conditions of stress combinations. Here, we highlight the challenge of defining "stress" in such complex natural scenarios. Therefore, defining stress hallmarks for different combinations is crucial. We discuss three examples of robust and dynamic plant acclimation systems, outlining specific plant responses to complex stress overlaps. (a) The high plasticity of root system architecture is a decisive feature in sustainable crop development in times of global climate change. (b) Similarly, broad sensory abilities and apparent control of cellular metabolism under adverse conditions through retrograde signaling make chloroplasts an ideal hub. Functional specificity of the chloroplast-associated molecular patterns (ChAMPs) under combined stresses needs further focus. (c) The molecular integration of several hormonal signaling pathways, which bring together all cellular information to initiate the adaptive changes, needs resolving.
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Affiliation(s)
- Vijay Kumar
- Biochemistry and Physiology of Plants, Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Melanie Wegener
- Biochemistry and Physiology of Plants, Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Madita Knieper
- Biochemistry and Physiology of Plants, Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Armağan Kaya
- Biochemistry and Physiology of Plants, Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Andrea Viehhauser
- Biochemistry and Physiology of Plants, Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Karl-Josef Dietz
- Biochemistry and Physiology of Plants, Faculty of Biology, Bielefeld University, Bielefeld, Germany.
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5
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Zhang X, Wang L, Pan T, Wu X, Shen J, Jiang L, Tajima H, Blumwald E, Qiu QS. Plastid KEA-type cation/H + antiporters are required for vacuolar protein trafficking in Arabidopsis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2023; 65:2157-2174. [PMID: 37252889 DOI: 10.1111/jipb.13537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 05/28/2023] [Indexed: 06/01/2023]
Abstract
Arabidopsis plastid antiporters KEA1 and KEA2 are critical for plastid development, photosynthetic efficiency, and plant development. Here, we show that KEA1 and KEA2 are involved in vacuolar protein trafficking. Genetic analyses found that the kea1 kea2 mutants had short siliques, small seeds, and short seedlings. Molecular and biochemical assays showed that seed storage proteins were missorted out of the cell and the precursor proteins were accumulated in kea1 kea2. Protein storage vacuoles (PSVs) were smaller in kea1 kea2. Further analyses showed that endosomal trafficking in kea1 kea2 was compromised. Vacuolar sorting receptor 1 (VSR1) subcellular localizations, VSR-cargo interactions, and p24 distribution on the endoplasmic reticulum (ER) and Golgi apparatus were affected in kea1 kea2. Moreover, plastid stromule growth was reduced and plastid association with the endomembrane compartments was disrupted in kea1 kea2. Stromule growth was regulated by the cellular pH and K+ homeostasis maintained by KEA1 and KEA2. The organellar pH along the trafficking pathway was altered in kea1 kea2. Overall, KEA1 and KEA2 regulate vacuolar trafficking by controlling the function of plastid stromules via adjusting pH and K+ homeostasis.
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Affiliation(s)
- Xiao Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, 810000, China
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou University, Lanzhou, 730000, China
| | - Lu Wang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, 810000, China
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou University, Lanzhou, 730000, China
| | - Ting Pan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
| | - Xuexia Wu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
| | - Jinbo Shen
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Hiromi Tajima
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Eduardo Blumwald
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Quan-Sheng Qiu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, 810000, China
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou University, Lanzhou, 730000, China
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6
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Yanagisawa M, Chuong SDX. Chloroplast Envelopes Play a Role in the Formation of Autophagy-Related Structures in Plants. PLANTS (BASEL, SWITZERLAND) 2023; 12:443. [PMID: 36771525 PMCID: PMC9920391 DOI: 10.3390/plants12030443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 06/18/2023]
Abstract
Autophagy is a degradation process of cytoplasmic components that is conserved in eukaryotes. One of the hallmark features of autophagy is the formation of double-membrane structures known as autophagosomes, which enclose cytoplasmic content destined for degradation. Although the membrane source for the formation of autophagosomes remains to be determined, recent studies indicate the involvement of various organelles in autophagosome biogenesis. In this study, we examined the autophagy process in Bienertia sinuspersici: one of four terrestrial plants capable of performing C4 photosynthesis in a single cell (single-cell C4 species). We demonstrated that narrow tubules (stromule-like structures) 30-50 nm in diameter appear to extend from chloroplasts to form the membrane-bound structures (autophagosomes or autophagy-related structures) in chlorenchyma cells of B. sinuspersici during senescence and under oxidative stress. Immunoelectron microscopic analysis revealed the localization of stromal proteins to the stromule-like structures, sequestering portions of the cytoplasm in chlorenchyma cells of oxidative stress-treated leaves of B. sinuspersici and Arabidopsis thaliana. Moreover, the fluorescent marker for autophagosomes GFP-ATG8, colocalized with the autophagic vacuole maker neutral red in punctate structures in close proximity to the chloroplasts of cells under oxidative stress conditions. Together our results implicate a role for chloroplast envelopes in the autophagy process induced during senescence or under certain stress conditions in plants.
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7
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Wang JZ, van de Ven W, Xiao Y, He X, Ke H, Yang P, Dehesh K. Reciprocity between a retrograde signal and a putative metalloprotease reconfigures plastidial metabolic and structural states. SCIENCE ADVANCES 2022; 8:eabo0724. [PMID: 35658042 PMCID: PMC9166295 DOI: 10.1126/sciadv.abo0724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/18/2022] [Indexed: 06/15/2023]
Abstract
Reconfiguration of the plastidial proteome in response to environmental cues is central to tailoring adaptive responses. To define the underlying mechanisms and consequences of these reconfigurations, we performed a suppressor screen, using a mutant (ceh1) accumulating high levels of a plastidial retrograde signaling metabolite, MEcPP. We isolated a revertant partially suppressing the dwarf stature and high salicylic acid of ceh1 and identified the mutation in a putative plastidial metalloprotease (VIR3). Biochemical analyses showed increased VIR3 levels in ceh1, accompanied by reduced abundance of VIR3-target enzymes, ascorbate peroxidase, and glyceraldehyde 3-phophate dehydrogenase B. These proteomic shifts elicited increased H2O2, salicylic acid, and MEcPP levels, as well as stromule formation. High light recapitulated VIR3-associated reconfiguration of plastidial metabolic and structural states. These results establish a link between a plastidial stress-inducible retrograde signaling metabolite and a putative metalloprotease and reveal how the reciprocity between the two components modulates plastidial metabolic and structural states, shaping adaptive responses.
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Affiliation(s)
- Jin-Zheng Wang
- Institute for Integrative Genome Biology and Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA 92521, USA
| | - Wilhelmina van de Ven
- Institute for Integrative Genome Biology and Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA 92521, USA
| | - Yanmei Xiao
- Department of Plant Biology, University of California, Davis, Davis, CA 95616, USA
| | - Xiang He
- Institute for Integrative Genome Biology and Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA 92521, USA
| | - Haiyan Ke
- Institute for Integrative Genome Biology and Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA 92521, USA
| | - Panyu Yang
- Department of Plant Biology, University of California, Davis, Davis, CA 95616, USA
| | - Katayoon Dehesh
- Institute for Integrative Genome Biology and Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA 92521, USA
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8
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Younes NA, Dawood MFA, Wardany AA. The phyto-impact of fluazinam fungicide on cellular structure, agro-physiological, and yield traits of pepper and eggplant crops. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:18064-18078. [PMID: 32170615 DOI: 10.1007/s11356-020-08289-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Accepted: 03/02/2020] [Indexed: 05/27/2023]
Abstract
Fluazinam is a widely used fungicide; most of the available information associated with its impact predominately on birds, invertebrates, mammals, and algae and scarce works studied its impact on crop plants. A two years-field experiments were conducted to study the response of pepper and eggplant to fluazinam at 0, 1, 2, and 3 times of the fluazinam-recommended dose (0, 0.5, 1, and 1.5 mL/L). The results revealed that fluazinam did not cause toxic effect on the tested plants except for temporary decline of shoot weights and lengths after 3 days of fluazinam application. However, fluazinam improved the physiological status of leaves via promoting metabolites, antioxidants, better membrane integrity, and adjustment of the redox status of fluazinam-sprayed plants. The ultrastructure changes of fluazinam-treated leaves associated with increment of chloroplasts' starch granules, giant nucleus, and elevated number of mitochondria. After 35 days of treatments, plant length of fungicide-treated plants was found to be higher than control and flowering time showed significant earliness. Furthermore, the yield traits were increased significantly in response to fluazinam. Our findings suggested that fluazinam-treated plants could initiate an early defense mechanism to mitigate the permanent growth retardation. This study could serve as a matrix for further studies to seek elucidation of plants' response to other doses of fluazinam. Graphical abstract .
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Affiliation(s)
- Nabil A Younes
- Horticulture Department, Faculty of Agriculture, Al-Azhar University-Assiut Branch, Assiut, Egypt.
| | - Mona F A Dawood
- Botany and Microbiology Department, Faculty of Science, Assiut University, Assiut, 71516, Egypt
| | - Ahmed A Wardany
- Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Assiut, 71524, Egypt
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9
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Dietz KJ, Wesemann C, Wegener M, Seidel T. Toward an Integrated Understanding of Retrograde Control of Photosynthesis. Antioxid Redox Signal 2019; 30:1186-1205. [PMID: 29463103 DOI: 10.1089/ars.2018.7519] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE Photosynthesis takes place in the chloroplast of eukaryotes, which occupies a large portion of the photosynthetic cell. The chloroplast function and integrity depend on intensive material and signal exchange between all genetic compartments and conditionally secure efficient photosynthesis and high fitness. Recent Advances: During the last two decades, the concept of mutual control of plastid performance by extraplastidic anterograde signals acting on the chloroplast and the feedback from the chloroplast to the extraplastidic space by retrograde signals has been profoundly revised and expanded. It has become clear that a complex set of diverse signals is released from the chloroplast and exceeds the historically proposed small number of information signals. Thus, it is also recognized that redox compounds and reactive oxygen species play a decisive role in retrograde signaling. CRITICAL ISSUES The diversity of processes controlled or modulated by the retrograde network covers all molecular levels, including RNA fate and translation, and also includes subcellular heterogeneity, indirect gating of other organelles' metabolism, and specific signaling routes and pathways, previously not considered. All these processes must be integrated for optimal adjustment of the chloroplast processes. Thus, evidence is presented suggesting that retrograde signaling affects translation, stress granule, and processing body (P-body) dynamics. FUTURE DIRECTIONS Redundancy of signal transduction elements, parallelisms of pathways, and conditionally alternative mechanisms generate a robust network and system that only tentatively can be assessed by use of single-site mutants.
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Affiliation(s)
- Karl-Josef Dietz
- Faculty of Biology, Department of Biochemistry and Physiology of Plants, University of Bielefeld, Bielefeld, Germany
| | - Corinna Wesemann
- Faculty of Biology, Department of Biochemistry and Physiology of Plants, University of Bielefeld, Bielefeld, Germany
| | - Melanie Wegener
- Faculty of Biology, Department of Biochemistry and Physiology of Plants, University of Bielefeld, Bielefeld, Germany
| | - Thorsten Seidel
- Faculty of Biology, Department of Biochemistry and Physiology of Plants, University of Bielefeld, Bielefeld, Germany
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10
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Michaud M, Jouhet J. Lipid Trafficking at Membrane Contact Sites During Plant Development and Stress Response. FRONTIERS IN PLANT SCIENCE 2019; 10:2. [PMID: 30713540 PMCID: PMC6346683 DOI: 10.3389/fpls.2019.00002] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 01/03/2019] [Indexed: 05/20/2023]
Abstract
The biogenesis of cellular membranes involves an important traffic of lipids from their site of synthesis to their final destination. Lipid transfer can be mediated by vesicular or non-vesicular pathways. The non-vesicular pathway requires the close apposition of two membranes to form a functional platform, called membrane contact sites (MCSs), where lipids are exchanged. These last decades, MCSs have been observed between virtually all organelles and a role in lipid transfer has been demonstrated for some of them. In plants, the lipid composition of membranes is highly dynamic and can be drastically modified in response to environmental changes. This highlights the importance of understanding the mechanisms involved in the regulation of membrane lipid homeostasis in plants. This review summarizes our current knowledge about the non-vesicular transport of lipids at MCSs in plants and its regulation during stress.
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11
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Erickson JL, Schattat MH. Shaping plastid stromules-principles of in vitro membrane tubulation applied in planta. CURRENT OPINION IN PLANT BIOLOGY 2018; 46:48-54. [PMID: 30041102 DOI: 10.1016/j.pbi.2018.07.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 07/01/2018] [Accepted: 07/06/2018] [Indexed: 05/10/2023]
Abstract
Plastids undergo drastic shape changes under stress, including the formation of stroma-filled tubules, or `stromules'. Stromules are dynamic, and may extend, branch and retract within minutes. There are two prerequisites for stromule extension: excess plastid membrane and a force(s) that shapes the membrane into a tubule. In vitro studies provide insight into the basic molecular machinery for tubulation, and are often cited when discussing stromule formation. In this review, we evaluate in vitro modes of tubulation in the context of stromule dynamics, and find that most mechanisms fail to explain stromule morphology and behavior observed in planta. Current data support a model of stromule formation relying on pulling motors (myosins and kinesins) and cytoskeleton (actin and microtubules).
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Affiliation(s)
- Jessica Lee Erickson
- Department of Plant Physiology, Institute for Biology, Martin Luther University Halle-Wittenberg, D-06099 Halle, Germany
| | - Martin Hartmut Schattat
- Department of Plant Physiology, Institute for Biology, Martin Luther University Halle-Wittenberg, D-06099 Halle, Germany.
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12
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Park E, Caplan JL, Dinesh-Kumar SP. Dynamic coordination of plastid morphological change by cytoskeleton for chloroplast-nucleus communication during plant immune responses. PLANT SIGNALING & BEHAVIOR 2018; 13:e1500064. [PMID: 30067472 PMCID: PMC6149414 DOI: 10.1080/15592324.2018.1500064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 06/20/2018] [Accepted: 06/27/2018] [Indexed: 05/27/2023]
Abstract
Considering their sessile life, plants must efficiently coordinate their resources and energy for maintaining their presence in normal living conditions and for defending themselves against environmental threats. Collaboration between multiple subcellular compartments is a common strategy in several biological processes to modify cells' architecture for their growth and development and to respond to acute changes in the environment. When plants defend themselves against microbial pathogens, chloroplasts generate tubular structures - so-called stromules- to facilitate chloroplast movement towards nuclei during innate immunity. Morphological changes and movements of stromules are directed by interactions with microtubule and actin cytoskeleton. Microtubules provide a direction for the stromule extension, while actin filaments restrict stromule retraction which provides a driving force for repositioning of chloroplast near nucleus during plant immune responses. These findings implicated a critical role for stromules in signal transduction from chloroplast to the nucleus in plant defense.
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Affiliation(s)
- Eunsook Park
- Department of Plant Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, Korea
- Department of Plant Biology and the Genome Center, College of Biological Sciences, University of California, Davis, CA, USA
| | - Jeffrey L. Caplan
- Department of Plant and Soil Sciences, College of Agriculture and Natural Resources, University of Delaware, Newark, DE, USA
- Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA
| | - Savithramma P. Dinesh-Kumar
- Department of Plant Biology and the Genome Center, College of Biological Sciences, University of California, Davis, CA, USA
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13
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Machado SR, Gregório EA, Rodrigues TM. Structural associations between organelle membranes in nectary parenchyma cells. PLANTA 2018; 247:1067-1076. [PMID: 29344723 DOI: 10.1007/s00425-018-2844-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/07/2018] [Indexed: 06/07/2023]
Abstract
The close association between membranes and organelles, and the intense chloroplast remodeling in parenchyma cells of extrafloral nectaries occurred only at the secretion time and suggest a relationship with the nectar secretion. Associations between membranes and organelles have been well documented in different tissues and cells of plants, but poorly explored in secretory cells. Here, we described the close physical juxtaposition between membranes and organelles, mainly with chloroplasts, in parenchyma cells of Citharexylum myrianthum (Verbenaeceae) extrafloral nectaries under transmission electron microscopy, using conventional and microwave fixation. At the time of nectar secretion, nectary parenchyma cells exhibit a multitude of different organelle and membrane associations as mitochondria-mitochondria, mitochondria-endoplasmic reticulum, mitochondria-chloroplast, chloroplast-nuclear envelope, mitochondria-nuclear envelope, chloroplast-plasmalemma, chloroplast-chloroplast, chloroplast-tonoplast, chloroplast-peroxisome, and mitochondria-peroxisome. These associations were visualized as amorphous electron-dense material, a network of dense fibrillar material and/or dense bridges. Chloroplasts exhibited protrusions variable in shape and extension, which bring them closer to each other and to plasmalemma, tonoplast, and nuclear envelope. Parenchyma cells in the pre- and post-secretory stages did not exhibit any association or juxtaposition of membranes and organelles, and chloroplast protrusions were absent. Chloroplasts had peripheral reticulum that was more developed in the secretory stage. We propose that such subcellular phenomena during the time of nectar secretion optimize the movement of signaling molecules and the exchange of metabolites. Our results open new avenues on the potential mechanisms of organelle contact in parenchyma nectary cells, and reveal new attributes of the secretory cells on the subcellular level.
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Affiliation(s)
- Silvia Rodrigues Machado
- Department of Botany, Institute of Biosciences of Botucatu (IBB), São Paulo State University (UNESP), Botucatu, SP, Brazil.
| | - Elisa A Gregório
- Center of Electron Microscopy (CME), Institute of Biosciences of Botucatu (IBB), São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Tatiane M Rodrigues
- Department of Botany, Institute of Biosciences of Botucatu (IBB), São Paulo State University (UNESP), Botucatu, SP, Brazil
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14
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Barton KA, Wozny MR, Mathur N, Jaipargas EA, Mathur J. Chloroplast behaviour and interactions with other organelles in Arabidopsis thaliana pavement cells. J Cell Sci 2018; 131:jcs.202275. [PMID: 28320821 DOI: 10.1242/jcs.202275] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 03/16/2017] [Indexed: 01/11/2023] Open
Abstract
Chloroplasts are a characteristic feature of green plants. Mesophyll cells possess the majority of chloroplasts and it is widely believed that, with the exception of guard cells, the epidermal layer in most higher plants does not contain chloroplasts. However, recent observations on Arabidopsis thaliana have shown a population of chloroplasts in pavement cells that are smaller than mesophyll chloroplasts and have a high stroma to grana ratio. Here, using stable transgenic lines expressing fluorescent proteins targeted to the plastid stroma, plasma membrane, endoplasmic reticulum, tonoplast, nucleus, mitochondria, peroxisomes, F-actin and microtubules, we characterize the spatiotemporal relationships between the pavement cell chloroplasts (PCCs) and their subcellular environment. Observations on the PCCs suggest a source-sink relationship between the epidermal and the mesophyll layers, and experiments with the Arabidopsis mutants glabra2 (gl2) and immutans (im), which show altered epidermal plastid development, underscored their developmental plasticity. Our findings lay down the foundation for further investigations aimed at understanding the precise role and contributions of PCCs in plant interactions with the environment.
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Affiliation(s)
- Kiah A Barton
- Laboratory of Plant Development and Interactions, Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road, Guelph, Ontario N1G2W1, Canada
| | - Michael R Wozny
- Laboratory of Plant Development and Interactions, Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road, Guelph, Ontario N1G2W1, Canada
| | - Neeta Mathur
- Laboratory of Plant Development and Interactions, Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road, Guelph, Ontario N1G2W1, Canada
| | - Erica-Ashley Jaipargas
- Laboratory of Plant Development and Interactions, Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road, Guelph, Ontario N1G2W1, Canada
| | - Jaideep Mathur
- Laboratory of Plant Development and Interactions, Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road, Guelph, Ontario N1G2W1, Canada
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15
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Hanson MR, Hines KM. Stromules: Probing Formation and Function. PLANT PHYSIOLOGY 2018; 176:128-137. [PMID: 29097392 PMCID: PMC5761818 DOI: 10.1104/pp.17.01287] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 10/30/2017] [Indexed: 05/18/2023]
Abstract
Stromules are plastid stroma-filled tubules that increase the surface area of the envelope and extend the reach of the plastid within the plant cell, affecting biosynthesis, metabolism, and signaling.
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Affiliation(s)
- Maureen R Hanson
- Department of Molecular Biology and Genetics, Cornell University, Biotechnology Building, Ithaca, New York 14853
| | - Kevin M Hines
- Department of Molecular Biology and Genetics, Cornell University, Biotechnology Building, Ithaca, New York 14853
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16
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Delfosse K, Wozny MR, Barton KA, Mathur N, Griffiths N, Mathur J. Plastid Envelope-Localized Proteins Exhibit a Stochastic Spatiotemporal Relationship to Stromules. FRONTIERS IN PLANT SCIENCE 2018; 9:754. [PMID: 29915611 PMCID: PMC5995270 DOI: 10.3389/fpls.2018.00754] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 05/16/2018] [Indexed: 05/13/2023]
Abstract
UNLABELLED Plastids in the viridiplantae sporadically form thin tubules called stromules that increase the interactive surface between the plastid and the surrounding cytoplasm. Several recent publications that report observations of certain proteins localizing to the extensions have then used the observations to suggest stromule-specific functions. The mechanisms by which specific localizations on these transient and sporadically formed extensions might occur remain unclear. Previous studies have yet to address the spatiotemporal relationship between a particular protein localization pattern and its distribution on an extended stromules and/or the plastid body. Here, we have used discrete protein patches found in several transgenic plants as fiducial markers to investigate this relationship. While we consider the inner plastid envelope-membrane localized protein patches of the GLUCOSE 6-PHOSPHATE/PHOSPHATE TRANSLOCATOR1 and the TRIOSE-PHOSPHATE/ PHOSPHATE TRANSLOCATOR 1 as artifacts of fluorescent fusion protein over-expression, stromule formation is not compromised in the respective stable transgenic lines that maintain normal growth and development. Our analysis of chloroplasts in the transgenic lines in the Arabidopsis Columbia background, and in the arc6 mutant, under stromule-inducing conditions shows that the possibility of finding a particular protein-enriched domain on an extended stromule or on a region of the main plastid body is stochastic. Our observations provide insights on the behavior of chloroplasts, the relationship between stromules and the plastid-body and strongly challenge claims of stromule-specific functions based solely upon protein localization to plastid extensions. ONE SENTENCE SUMMARY Observations of the spatiotemporal relationship between plastid envelope localized fluorescent protein fusions of two sugar-phosphate transporters and stromules suggest a stochastic rather than specific localization pattern that questions the idea of independent functions for stromules.
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17
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Mueller-Schuessele SJ, Michaud M. Plastid Transient and Stable Interactions with Other Cell Compartments. Methods Mol Biol 2018; 1829:87-109. [PMID: 29987716 DOI: 10.1007/978-1-4939-8654-5_6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Plastids are organelles delineated by two envelopes that play important roles in different cellular processes such as energy production or lipid biosynthesis. To regulate their biogenesis and their function, plastids have to communicate with other cellular compartments. This communication can be mediated by signaling molecules and by the establishment of direct contacts between the plastid envelope and other organelles such as the endoplasmic reticulum, the mitochondria, the plasma membrane, the peroxisomes and the nucleus. These interactions are highly dynamic and respond to different biotic and abiotic stresses. However, the mechanisms involved in the formation of plastid-organelle contact sites and their functions are still enigmatic. In this chapter, we summarize our current knowledge about plastid contact sites and their role in the regulation of plastid biogenesis and function.
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Affiliation(s)
| | - Morgane Michaud
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA. .,Laboratoire de Physiologie Cellulaire et Végétale, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Commissariat à l'Energie Atomique et aux Energies Alternatives, CEA Grenoble, UMR5168, Université Grenoble Alpes, Grenoble, France.
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18
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Barczak-Brzyżek A, Kiełkiewicz M, Górecka M, Kot K, Karpińska B, Filipecki M. Abscisic Acid Insensitive 4 transcription factor is an important player in the response of Arabidopsis thaliana to two-spotted spider mite (Tetranychus urticae) feeding. EXPERIMENTAL & APPLIED ACAROLOGY 2017; 73:317-326. [PMID: 29210003 PMCID: PMC5727149 DOI: 10.1007/s10493-017-0203-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 11/24/2017] [Indexed: 05/04/2023]
Abstract
Plants growing in constantly changeable environmental conditions are compelled to evolve regulatory mechanisms to cope with biotic and abiotic stresses. Effective defence to invaders is largely connected with phytohormone regulation, resulting in the production of numerous defensive proteins and specialized metabolites. In our work, we elucidated the role of the Abscisic Acid Insensitive 4 (ABI4) transcription factor in the plant response to the two-spotted spider mite (TSSM). This polyphagous mite is one of the most destructive herbivores, which sucks mesophyll cells of numerous crop and wild plants. Compared to the wild-type (Col-0) Arabidopsis thaliana plants, the abi4 mutant demonstrated increased susceptibility to TSSM, reflected as enhanced female fecundity and greater frequency of mite leaf damage after trypan blue staining. Because ABI4 is regarded as an important player in the plastid-to-nucleus retrograde signalling process, we investigated the plastid envelope membrane dynamics using stroma-associated fluorescent marker. Our results indicated a clear increase in the number of stroma-filled tubular structures deriving from the plastid membrane (stromules) in the close proximity of the site of mite leaf damage, highlighting the importance of chloroplast-derived signals in the response to TSSM feeding activity.
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Affiliation(s)
| | | | | | - Karol Kot
- Warsaw University of Life Sciences - SGGW, Warsaw, Poland
| | - Barbara Karpińska
- Warsaw University of Life Sciences - SGGW, Warsaw, Poland
- Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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19
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Płachno BJ, Świątek P, Jobson RW, Małota K, Brutkowski W. Serial block face SEM visualization of unusual plant nuclear tubular extensions in a carnivorous plant (Utricularia, Lentibulariaceae). ANNALS OF BOTANY 2017; 120:673-680. [PMID: 28541416 PMCID: PMC5691799 DOI: 10.1093/aob/mcx042] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 02/09/2017] [Accepted: 03/23/2017] [Indexed: 05/22/2023]
Abstract
Background and Aims In Utricularia nelumbifolia , the nuclei of placental nutritive tissue possess unusually shaped projections not known to occur in any other flowering plant. The main aim of the study was to document the morphology and ultrastructure of these unusual nuclei. In addition, the literature was searched to find examples of nuclear tubular projections in other plant groups, and the nuclei of closely related species of Utricularia (i.e. sects Iperua , Orchidioides , Foliosa and Utricularia ) were examined. Methods To visualize the complexity of the nuclear structures, transmission electron microscopy (TEM) was used, and 3-D ultrastructural reconstructions were made using the serial block face scanning electron microscopy (SBEM) technique. The nuclei of 11 Utricularia species, i.e. U. nelumbifolia , U. reniformis , U. cornigera , U. nephrophylla (sect. Iperua ), U. asplundii , U. alpina , U. quelchii (sect. Orchidioides ), U. longifolia (sect. Foliosa ), U. intermedia , U. minor and U. gibba (sect. Utricularia ) were examined. Key Results Of the 11 Utricularia species examined, the spindle-like tubular projections (approx. 5 μm long) emanating from resident nuclei located in placental nutritive tissues were observed only in U. nelumbifolia . These tubular nuclear extensions contained chromatin distributed along hexagonally shaped tubules. The apices of the projections extended into the cell plasma membrane, and in many cases also made contact at the two opposing cellular poles, and with plasmodesmata via a short cisterna of the cortical endoplasmic reticulum. Images from the SBEM provide some evidence that the nuclear projections are making contact with those of neighbouring cells. Conclusions The term chromatubules (chromatin-filled tubules) for the nuclear projections of U. nelumbifolia placental tissue was proposed here. Due to the apparent association with the plasma membrane and plasmodesmata, it was also speculated that chromatubules are involved in nucleus-cell-cell communication. However, further experimental evidence is required before any functional hypothesis can be entertained.
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Affiliation(s)
- Bartosz J Płachno
- Department of Plant Cytology and Embryology, Jagiellonian University in Kraków, 9 Gronostajowa St., Cracow, Poland
| | - Piotr Świątek
- Department of Animal Histology and Embryology, University of Silesia in Katowice, 9 Bankowa St., 40-007 Katowice, Poland
| | - Richard W Jobson
- National Herbarium of New South Wales, Mrs Macquaries Road, Sydney, NSW 2000 Australia
| | - Karol Małota
- Department of Animal Histology and Embryology, University of Silesia in Katowice, 9 Bankowa St., 40-007 Katowice, Poland
| | - Wojciech Brutkowski
- Laboratory for Imaging Tissue Structure and Function, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St., 02-093 Warszawa, Poland
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20
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Hatakeyama Y, Ueno O. Intracellular position of mitochondria in mesophyll cells differs between C 3 and C 4 grasses. JOURNAL OF PLANT RESEARCH 2017; 130:885-892. [PMID: 28434121 DOI: 10.1007/s10265-017-0947-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 04/06/2017] [Indexed: 06/07/2023]
Abstract
In C3 plants, part of the CO2 fixed during photosynthesis in chloroplasts is released from mitochondria during photorespiration by decarboxylation of glycine via glycine decarboxylase (GDC), thereby reducing photosynthetic efficiency. The apparent positioning of most mitochondria in the interior (vacuole side of chloroplasts) of mesophyll cells in C3 grasses would increase the efficiency of refixation of CO2 released from mitochondria by ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) in chloroplasts. Therefore, in mesophyll cells of C4 grasses, which lack both GDC and Rubisco, the mitochondria ought not to be positioned the same way as in C3 mesophyll cells. To test this hypothesis, we investigated the intracellular position of mitochondria in mesophyll cells of 14 C4 grasses of different C4 subtypes and subfamilies (Chloridoideae, Micrairoideae, and Panicoideae) and a C3-C4 intermediate grass, Steinchisma hians, under an electron microscope. In C4 mesophyll cells, most mitochondria were positioned adjacent to the cell wall, which clearly differs from the positioning in C3 mesophyll cells. In S. hians mesophyll cells, the positioning was similar to that in C3 cells. These results suggest that the mitochondrial positioning in C4 mesophyll cells reflects the absence of both GDC and Rubisco in the mesophyll cells and the high activity of phosphoenolpyruvate carboxylase. In contrast, the relationship between the mitochondrial positioning and enzyme distribution in S. hians is complex, but the positioning may be related to the capture of respiratory CO2 by Rubisco. Our study provides new possible insight into the physiological role of mitochondrial positioning in photosynthetic cells.
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Affiliation(s)
- Yuto Hatakeyama
- Graduate School of Bioresources and Bioenvironmental Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka, 812-8581, Japan
- NARO Kyushu Okinawa Agricultural Research Center, Chikugoshi, Fukuoka, 833-0027, Japan
| | - Osamu Ueno
- Graduate School of Bioresources and Bioenvironmental Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka, 812-8581, Japan.
- Faculty of Agriculture, Kyushu University, Hakozaki 6-10-1, Fukuoka, 812-8581, Japan.
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21
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Daher Z, Recorbet G, Solymosi K, Wienkoop S, Mounier A, Morandi D, Lherminier J, Wipf D, Dumas-Gaudot E, Schoefs B. Changes in plastid proteome and structure in arbuscular mycorrhizal roots display a nutrient starvation signature. PHYSIOLOGIA PLANTARUM 2017; 159:13-29. [PMID: 27558913 DOI: 10.1111/ppl.12505] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/17/2016] [Accepted: 07/18/2016] [Indexed: 05/21/2023]
Abstract
During arbuscular mycorrhizal symbiosis, arbuscule-containing root cortex cells display a proliferation of plastids, a feature usually ascribed to an increased plant anabolism despite the lack of studies focusing on purified root plastids. In this study, we investigated mycorrhiza-induced changes in plastidic pathways by performing a label-free comparative subcellular quantitative proteomic analysis targeted on plastid-enriched fractions isolated from Medicago truncatula roots, coupled to a cytological analysis of plastid structure. We identified 490 root plastid protein candidates, among which 79 changed in abundance upon mycorrhization, as inferred from spectral counting. According to cross-species sequence homology searches, the mycorrhiza-responsive proteome was enriched in proteins experimentally localized in thylakoids, whereas it was depleted of proteins ascribed predominantly to amyloplasts. Consistently, the analysis of plastid morphology using transmission electron microscopy indicated that starch depletion associated with the proliferation of membrane-free and tubular membrane-containing plastids was a feature specific to arbusculated cells. The loss of enzymes involved in carbon/nitrogen assimilation and provision of reducing power, coupled to macromolecule degradation events in the plastid-enriched fraction of mycorrhizal roots that paralleled lack of starch accumulation in arbusculated cells, lead us to propose that arbuscule functioning elicits a nutrient starvation and an oxidative stress signature that may prime arbuscule breakdown.
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Affiliation(s)
- Zeina Daher
- Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, Pôle Interactions Plantes Microrganismes, Dijon cedex 21065, France
| | - Ghislaine Recorbet
- Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, Pôle Interactions Plantes Microrganismes, Dijon cedex 21065, France
| | - Katalin Solymosi
- Department of Plant Anatomy, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Stefanie Wienkoop
- Department of Molecular System Biology, University of Vienna, Vienna 1090, Austria
| | - Arnaud Mounier
- Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, Pôle Interactions Plantes Microrganismes, Dijon cedex 21065, France
| | - Dominique Morandi
- Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, Pôle Interactions Plantes Microrganismes, Dijon cedex 21065, France
| | - Jeannine Lherminier
- Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, Pôle Interactions Plantes Microrganismes, Dijon cedex 21065, France
| | - Daniel Wipf
- Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, Pôle Interactions Plantes Microrganismes, Dijon cedex 21065, France
| | - Eliane Dumas-Gaudot
- Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, Pôle Interactions Plantes Microrganismes, Dijon cedex 21065, France
| | - Benoît Schoefs
- MicroMar, Mer, Molécules, Santé, UBL, Université du Maine, Le Mans Cedex 9 72085, France
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22
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Brunkard JO, Runkel AM, Zambryski P. Visualizing Stromule Frequency with Fluorescence Microscopy. J Vis Exp 2016:54692. [PMID: 27911400 PMCID: PMC5226277 DOI: 10.3791/54692] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Stromules, or "stroma-filled tubules", are narrow, tubular extensions from the surface of the chloroplast that are universally observed in plant cells but whose functions remain mysterious. Alongside growing attention on the role of chloroplasts in coordinating plant responses to stress, interest in stromules and their relationship to chloroplast signaling dynamics has increased in recent years, aided by advances in fluorescence microscopy and protein fluorophores that allow for rapid, accurate visualization of stromule dynamics. Here, we provide detailed protocols to assay stromule frequency in the epidermal chloroplasts of Nicotiana benthamiana, an excellent model system for investigating chloroplast stromule biology. We also provide methods for visualizing chloroplast stromules in vitro by extracting chloroplasts from leaves. Finally, we outline sampling strategies and statistical approaches to analyze differences in stromule frequencies in response to stimuli, such as environmental stress, chemical treatments, or gene silencing. Researchers can use these protocols as a starting point to develop new methods for innovative experiments to explore how and why chloroplasts make stromules.
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Affiliation(s)
- Jacob O Brunkard
- Plant Gene Expression Center, Agricultural Research Service, USDA
| | - Anne M Runkel
- Department of Plant and Microbial Biology, University of California, Berkeley
| | - Patricia Zambryski
- Department of Plant and Microbial Biology, University of California, Berkeley;
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23
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Para A, Muhammad D, Orozco-Nunnelly DA, Memishi R, Alvarez S, Naldrett MJ, Warpeha KM. The Dehydratase ADT3 Affects ROS Homeostasis and Cotyledon Development. PLANT PHYSIOLOGY 2016; 172:1045-1060. [PMID: 27540109 PMCID: PMC5047074 DOI: 10.1104/pp.16.00464] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 08/15/2016] [Indexed: 05/25/2023]
Abstract
During the transition from seed to seedling, emerging embryos strategically balance available resources between building up defenses against environmental threats and initiating the developmental program that promotes the switch to autotrophy. We present evidence of a critical role for the phenylalanine (Phe) biosynthetic activity of AROGENATE DEHYDRATASE3 (ADT3) in coordinating reactive oxygen species (ROS) homeostasis and cotyledon development in etiolated Arabidopsis (Arabidopsis thaliana) seedlings. We show that ADT3 is expressed in the cotyledon and shoot apical meristem, mainly in the cytosol, and that the epidermis of adt3 cotyledons contains higher levels of ROS Genome-wide proteomics of the adt3 mutant revealed a general down-regulation of plastidic proteins and ROS-scavenging enzymes, corroborating the hypothesis that the ADT3 supply of Phe is required to control ROS concentration and distribution to protect cellular components. In addition, loss of ADT3 disrupts cotyledon epidermal patterning by affecting the number and expansion of pavement cells and stomata cell fate specification; we also observed severe alterations in mesophyll cells, which lack oil bodies and normal plastids. Interestingly, up-regulation of the pathway leading to cuticle production is accompanied by an abnormal cuticle structure and/or deposition in the adt3 mutant. Such impairment results in an increase in cell permeability and provides a link to understand the cell defects in the adt3 cotyledon epidermis. We suggest an additional role of Phe in supplying nutrients to the young seedling.
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Affiliation(s)
- Alessia Para
- Weinberg College of Art and Science, Northwestern University, Evanston, Illinois 60208 (A.P.);Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607 (D.M., D.A.O.-N., R.M., K.M.W.); andProteomics and Mass Spectrometry Facility, Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (S.A., M.J.N.)
| | - DurreShahwar Muhammad
- Weinberg College of Art and Science, Northwestern University, Evanston, Illinois 60208 (A.P.);Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607 (D.M., D.A.O.-N., R.M., K.M.W.); andProteomics and Mass Spectrometry Facility, Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (S.A., M.J.N.)
| | - Danielle A Orozco-Nunnelly
- Weinberg College of Art and Science, Northwestern University, Evanston, Illinois 60208 (A.P.);Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607 (D.M., D.A.O.-N., R.M., K.M.W.); andProteomics and Mass Spectrometry Facility, Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (S.A., M.J.N.)
| | - Ramis Memishi
- Weinberg College of Art and Science, Northwestern University, Evanston, Illinois 60208 (A.P.);Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607 (D.M., D.A.O.-N., R.M., K.M.W.); andProteomics and Mass Spectrometry Facility, Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (S.A., M.J.N.)
| | - Sophie Alvarez
- Weinberg College of Art and Science, Northwestern University, Evanston, Illinois 60208 (A.P.);Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607 (D.M., D.A.O.-N., R.M., K.M.W.); andProteomics and Mass Spectrometry Facility, Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (S.A., M.J.N.)
| | - Michael J Naldrett
- Weinberg College of Art and Science, Northwestern University, Evanston, Illinois 60208 (A.P.);Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607 (D.M., D.A.O.-N., R.M., K.M.W.); andProteomics and Mass Spectrometry Facility, Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (S.A., M.J.N.)
| | - Katherine M Warpeha
- Weinberg College of Art and Science, Northwestern University, Evanston, Illinois 60208 (A.P.);Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607 (D.M., D.A.O.-N., R.M., K.M.W.); andProteomics and Mass Spectrometry Facility, Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (S.A., M.J.N.)
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24
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Serrano I, Audran C, Rivas S. Chloroplasts at work during plant innate immunity. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3845-54. [PMID: 26994477 DOI: 10.1093/jxb/erw088] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The major role played by chloroplasts during light harvesting, energy production, redox homeostasis, and retrograde signalling processes has been extensively characterized. Beyond the obvious link between chloroplast functions in primary metabolism and as providers of photosynthesis-derived carbon sources and energy, a growing body of evidence supports a central role for chloroplasts as integrators of environmental signals and, more particularly, as key defence organelles. Here, we review the importance of these organelles as primary sites for the biosynthesis and transmission of pro-defence signals during plant immune responses. In addition, we highlight interorganellar communication as a crucial process for amplification of the immune response. Finally, molecular strategies used by microbes to manipulate, directly or indirectly, the production/function of defence-related signalling molecules and subvert chloroplast-based defences are also discussed.
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Affiliation(s)
- Irene Serrano
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Corinne Audran
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Susana Rivas
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
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25
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Chan KX, Phua SY, Crisp P, McQuinn R, Pogson BJ. Learning the Languages of the Chloroplast: Retrograde Signaling and Beyond. ANNUAL REVIEW OF PLANT BIOLOGY 2016; 67:25-53. [PMID: 26735063 DOI: 10.1146/annurev-arplant-043015-111854] [Citation(s) in RCA: 339] [Impact Index Per Article: 42.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The chloroplast can act as an environmental sensor, communicating with the cell during biogenesis and operation to change the expression of thousands of proteins. This process, termed retrograde signaling, regulates expression in response to developmental cues and stresses that affect photosynthesis and yield. Recent advances have identified many signals and pathways-including carotenoid derivatives, isoprenes, phosphoadenosines, tetrapyrroles, and heme, together with reactive oxygen species and proteins-that build a communication network to regulate gene expression, RNA turnover, and splicing. However, retrograde signaling pathways have been viewed largely as a means of bilateral communication between organelles and nuclei, ignoring their potential to interact with hormone signaling and the cell as a whole to regulate plant form and function. Here, we discuss new findings on the processes by which organelle communication is initiated, transmitted, and perceived, not only to regulate chloroplastic processes but also to intersect with cellular signaling and alter physiological responses.
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Affiliation(s)
- Kai Xun Chan
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia; , , , ,
| | - Su Yin Phua
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia; , , , ,
| | - Peter Crisp
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia; , , , ,
| | - Ryan McQuinn
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia; , , , ,
| | - Barry J Pogson
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia; , , , ,
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Allen DK. Assessing compartmentalized flux in lipid metabolism with isotopes. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1226-1242. [PMID: 27003250 DOI: 10.1016/j.bbalip.2016.03.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 03/13/2016] [Accepted: 03/14/2016] [Indexed: 12/28/2022]
Abstract
Metabolism in plants takes place across multiple cell types and within distinct organelles. The distributions equate to spatial heterogeneity; though the limited means to experimentally assess metabolism frequently involve homogenizing tissues and mixing metabolites from different locations. Most current isotope investigations of metabolism therefore lack the ability to resolve spatially distinct events. Recognition of this limitation has resulted in inspired efforts to advance metabolic flux analysis and isotopic labeling techniques. Though a number of these efforts have been applied to studies in central metabolism; recent advances in instrumentation and techniques present an untapped opportunity to make similar progress in lipid metabolism where the use of stable isotopes has been more limited. These efforts will benefit from sophisticated radiolabeling reports that continue to enrich our knowledge on lipid biosynthetic pathways and provide some direction for stable isotope experimental design and extension of MFA. Evidence for this assertion is presented through the review of several elegant stable isotope studies and by taking stock of what has been learned from radioisotope investigations when spatial aspects of metabolism were considered. The studies emphasize that glycerolipid production occurs across several locations with assembly of lipids in the ER or plastid, fatty acid biosynthesis occurring in the plastid, and the generation of acetyl-CoA and glycerol-3-phosphate taking place at multiple sites. Considering metabolism in this context underscores the cellular and subcellular organization that is important to enhanced production of glycerolipids in plants. An attempt is made to unify salient features from a number of reports into a diagrammatic model of lipid metabolism and propose where stable isotope labeling experiments and further flux analysis may help address questions in the field. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner.
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Affiliation(s)
- Doug K Allen
- United States Department of Agriculture, Agricultural Research Service, 975 North Warson Road, St. Louis, MO 63132, United States; Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO 63132, United States.
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Larkin RM, Stefano G, Ruckle ME, Stavoe AK, Sinkler CA, Brandizzi F, Malmstrom CM, Osteryoung KW. REDUCED CHLOROPLAST COVERAGE genes from Arabidopsis thaliana help to establish the size of the chloroplast compartment. Proc Natl Acad Sci U S A 2016; 113:E1116-25. [PMID: 26862170 PMCID: PMC4776492 DOI: 10.1073/pnas.1515741113] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Eukaryotic cells require mechanisms to establish the proportion of cellular volume devoted to particular organelles. These mechanisms are poorly understood. From a screen for plastid-to-nucleus signaling mutants in Arabidopsis thaliana, we cloned a mutant allele of a gene that encodes a protein of unknown function that is homologous to two other Arabidopsis genes of unknown function and to FRIENDLY, which was previously shown to promote the normal distribution of mitochondria in Arabidopsis. In contrast to FRIENDLY, these three homologs of FRIENDLY are found only in photosynthetic organisms. Based on these data, we proposed that FRIENDLY expanded into a small gene family to help regulate the energy metabolism of cells that contain both mitochondria and chloroplasts. Indeed, we found that knocking out these genes caused a number of chloroplast phenotypes, including a reduction in the proportion of cellular volume devoted to chloroplasts to 50% of wild type. Thus, we refer to these genes as REDUCED CHLOROPLAST COVERAGE (REC). The size of the chloroplast compartment was reduced most in rec1 mutants. The REC1 protein accumulated in the cytosol and the nucleus. REC1 was excluded from the nucleus when plants were treated with amitrole, which inhibits cell expansion and chloroplast function. We conclude that REC1 is an extraplastidic protein that helps to establish the size of the chloroplast compartment, and that signals derived from cell expansion or chloroplasts may regulate REC1.
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Affiliation(s)
- Robert M Larkin
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824; Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824
| | - Giovanni Stefano
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824
| | - Michael E Ruckle
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824
| | - Andrea K Stavoe
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824
| | - Christopher A Sinkler
- Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824
| | - Federica Brandizzi
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824; Michigan State University-Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824
| | - Carolyn M Malmstrom
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824
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28
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Ho J, Theg SM. The Formation of Stromules In Vitro from Chloroplasts Isolated from Nicotiana benthamiana. PLoS One 2016; 11:e0146489. [PMID: 26840974 PMCID: PMC4739594 DOI: 10.1371/journal.pone.0146489] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 12/17/2015] [Indexed: 11/23/2022] Open
Abstract
Stromules are stroma-containing tubules that have been observed to emanate from the main plastidic body in vivo. These structures have been shown to require cytoskeletal components for movement. Though numerous studies have shown a close association with the endoplasmic reticulum, nucleus, mitochondria, and other plastids, the mechanism of formation and their overall function remain unknown. A limiting factor in studying these structures has been the lack of a reconstituted system for in vitro stromule formation. In this study, stromule formation was induced in vitro by adding a plant extract fraction that is greater than 100 kDa to a population of isolated chloroplasts. Kinetic measurements show that stromule formation occurs within ~10 seconds after the addition of the plant extract fraction. Heat inactivation and apyrase treatment reveal that the stromule stimulating compound found in the extract fraction is a protein or protein complex 100 kDa or greater. The formation of the stromules in vitro with isolated chloroplasts and a concentrated fraction of cell extract opens an avenue for the biochemical dissection of this process that has heretofore been studied only in vivo.
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Affiliation(s)
- Jonathan Ho
- Department of Plant Biology, University of California Davis, Davis, California, United States of America
| | - Steven M. Theg
- Department of Plant Biology, University of California Davis, Davis, California, United States of America
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29
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Buchner O, Moser T, Karadar M, Roach T, Kranner I, Holzinger A. Formation of chloroplast protrusions and catalase activity in alpine Ranunculus glacialis under elevated temperature and different CO2/O2 ratios. PROTOPLASMA 2015; 252:1613-9. [PMID: 25701381 PMCID: PMC4628086 DOI: 10.1007/s00709-015-0778-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 02/09/2015] [Indexed: 05/23/2023]
Abstract
Chloroplast protrusions (CPs) have frequently been observed in plants, but their significance to plant metabolism remains largely unknown. We investigated in the alpine plant Ranunculus glacialis L. treated under various CO2 concentrations if CP formation is related to photorespiration, specifically focusing on hydrogen peroxide (H2O2) metabolism. Immediately after exposure to different CO2 concentrations, the formation of CPs in leaf mesophyll cells was assessed and correlated to catalase (CAT) and ascorbate peroxidase (APX) activities. Under natural irradiation, the relative proportion of chloroplasts with protrusions (rCP) was highest (58.7 %) after exposure to low CO2 (38 ppm) and was lowest (3.0 %) at high CO2 (10,000 ppm). The same relationship was found for CAT activity, which decreased from 34.7 nkat mg(-1) DW under low CO2 to 18.4 nkat mg(-1) DW under high CO2, while APX activity did not change significantly. When exposed to natural CO2 concentration (380 ppm) in darkness, CP formation was significantly lower (18.2 %) compared to natural solar irradiation (41.3 %). In summary, CP formation and CAT activity are significantly increased under conditions that favour photorespiration, while in darkness or at high CO2 concentration under light, CP formation is significantly lower, providing evidence for an association between CPs and photorespiration.
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Affiliation(s)
- Othmar Buchner
- Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria.
| | - Tim Moser
- Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria
| | - Matthias Karadar
- Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria
| | - Thomas Roach
- Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria
| | - Ilse Kranner
- Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria
| | - Andreas Holzinger
- Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria
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30
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Abstract
The chloroplast is a primary site for the production of immune signals in plants. In this issue of Developmental Cell, Caplan et al. (2015) report that chloroplasts send out stromules as signal conduits for transmission of these immune signals to the nucleus during effector-triggered immunity.
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Affiliation(s)
- Yangnan Gu
- Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Department of Biology, P.O. Box 90338, Duke University, Durham, NC 27708, USA
| | - Xinnian Dong
- Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Department of Biology, P.O. Box 90338, Duke University, Durham, NC 27708, USA.
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31
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Brunkard JO, Runkel AM, Zambryski PC. Chloroplasts extend stromules independently and in response to internal redox signals. Proc Natl Acad Sci U S A 2015; 112:10044-9. [PMID: 26150490 PMCID: PMC4538653 DOI: 10.1073/pnas.1511570112] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
A fundamental mystery of plant cell biology is the occurrence of "stromules," stroma-filled tubular extensions from plastids (such as chloroplasts) that are universally observed in plants but whose functions are, in effect, completely unknown. One prevalent hypothesis is that stromules exchange signals or metabolites between plastids and other subcellular compartments, and that stromules are induced during stress. Until now, no signaling mechanisms originating within the plastid have been identified that regulate stromule activity, a critical missing link in this hypothesis. Using confocal and superresolution 3D microscopy, we have shown that stromules form in response to light-sensitive redox signals within the chloroplast. Stromule frequency increased during the day or after treatment with chemicals that produce reactive oxygen species specifically in the chloroplast. Silencing expression of the chloroplast NADPH-dependent thioredoxin reductase, a central hub in chloroplast redox signaling pathways, increased chloroplast stromule frequency, whereas silencing expression of nuclear genes related to plastid genome expression and tetrapyrrole biosynthesis had no impact on stromules. Leucoplasts, which are not photosynthetic, also made more stromules in the daytime. Leucoplasts did not respond to the same redox signaling pathway but instead increased stromule formation when exposed to sucrose, a major product of photosynthesis, although sucrose has no impact on chloroplast stromule frequency. Thus, different types of plastids make stromules in response to distinct signals. Finally, isolated chloroplasts could make stromules independently after extraction from the cytoplasm, suggesting that chloroplast-associated factors are sufficient to generate stromules. These discoveries demonstrate that chloroplasts are remarkably autonomous organelles that alter their stromule frequency in reaction to internal signal transduction pathways.
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Affiliation(s)
- Jacob O Brunkard
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Anne M Runkel
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Patricia C Zambryski
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
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32
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Hanson MR. Reactive oxygen species signal chloroplasts to extend themselves. Proc Natl Acad Sci U S A 2015; 112:9799-800. [PMID: 26204917 PMCID: PMC4538680 DOI: 10.1073/pnas.1512645112] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- Maureen R Hanson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
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33
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Green to red photoconversion of GFP for protein tracking in vivo. Sci Rep 2015; 5:11771. [PMID: 26148899 PMCID: PMC4493561 DOI: 10.1038/srep11771] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 04/27/2015] [Indexed: 12/22/2022] Open
Abstract
A variety of fluorescent proteins have been identified that undergo shifts in spectral emission properties over time or once they are irradiated by ultraviolet or blue light. Such proteins are finding application in following the dynamics of particular proteins or labelled organelles within the cell. However, before genes encoding these fluorescent proteins were available, many proteins have already been labelled with GFP in transgenic cells; a number of model organisms feature collections of GFP-tagged lines and organisms. Here we describe a fast, localized and non-invasive method for GFP photoconversion from green to red. We demonstrate its use in transgenic plant, Drosophila and mammalian cells in vivo. While genes encoding fluorescent proteins specifically designed for photoconversion will usually be advantageous when creating new transgenic lines, our method for photoconversion of GFP allows the use of existing GFP-tagged transgenic lines for studies of dynamic processes in living cells.
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Chloroplast protrusions in leaves of Ranunculus glacialis
L. respond significantly to different ambient conditions, but are not related to temperature stress. PLANT, CELL & ENVIRONMENT 2015; 38:1347-56. [PMID: 25393014 PMCID: PMC5098225 DOI: 10.1111/pce.12483] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 11/06/2014] [Accepted: 11/07/2014] [Indexed: 05/09/2023]
Abstract
The occurrence of chloroplast protrusions (CPs) in leaves of Ranunculus glacialis
L. in response to different environmental conditions was assessed. CPs occur highly dynamically. They do not contain thylakoids and their physiological function is still largely unknown. Controlled in situ sampling showed that CP formation follows a pronounced diurnal rhythm. Between 2 and 27 °C the relative proportion of chloroplasts with CPs (rCP) showed a significant positive correlation to leaf temperature (TL; 0.793, P < 0.01), while irradiation intensity had a minor effect on rCP. In situ shading and controlled laboratory experiments confirmed the significant influence of TL. Under moderate irradiation intensity, an increase of TL up to 25 °C significantly promoted CP formation, while a further increase to 37 °C led to a decrease. Furthermore, rCP values were lower in darkness and under high irradiation intensity. Gas treatment at 2000 ppm CO2/2% O2 led to a significant decrease of rCP, suggesting a possible involvement of photorespiration in CP formation. Our findings demonstrate that in R. glacialis, CPs are neither a rare phenomenon nor a result of heat or light stress; on the contrary, they seem to be most abundant under moderate temperature and non‐stress irradiation conditions. Chloroplast protrusions (CPs) are stroma‐filled areas not containing any thylakoids. They are formed dynamically and the physiological function is still largely unknown. We conducted field and laboratory experiments on the nival plant species Ranunculus glacialisL. and demonstrate that CP formation follows a pronounced diurnal rhythm. CPs are neither a result of heat or light stress but seem to be most abundant under moderate temperature and non‐stress irradiation conditions.
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35
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Chloroplast Stromules Function during Innate Immunity. Dev Cell 2015; 34:45-57. [PMID: 26120031 DOI: 10.1016/j.devcel.2015.05.011] [Citation(s) in RCA: 220] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 02/04/2015] [Accepted: 05/13/2015] [Indexed: 12/11/2022]
Abstract
Inter-organellar communication is vital for successful innate immune responses that confer defense against pathogens. However, little is known about how chloroplasts, which are a major production site of pro-defense molecules, communicate and coordinate with other organelles during defense. Here we show that chloroplasts send out dynamic tubular extensions called stromules during innate immunity or exogenous application of the pro-defense signals, hydrogen peroxide (H2O2) and salicylic acid. Interestingly, numerous stromules surround nuclei during defense response, and these connections correlate with an accumulation of chloroplast-localized NRIP1 defense protein and H2O2 in the nucleus. Furthermore, silencing and knockout of chloroplast unusual positioning 1 (CHUP1) that encodes a chloroplast outer envelope protein constitutively induces stromules in the absence of pathogen infection and enhances programmed cell death. These results support a model in which stromules aid in the amplification and/or transport of pro-defense signals into the nucleus and other subcellular compartments during immunity.
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36
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Delfosse K, Wozny MR, Jaipargas EA, Barton KA, Anderson C, Mathur J. Fluorescent Protein Aided Insights on Plastids and their Extensions: A Critical Appraisal. FRONTIERS IN PLANT SCIENCE 2015; 6:1253. [PMID: 26834765 PMCID: PMC4719081 DOI: 10.3389/fpls.2015.01253] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 12/21/2015] [Indexed: 05/20/2023]
Abstract
Multi-colored fluorescent proteins targeted to plastids have provided new insights on the dynamic behavior of these organelles and their interactions with other cytoplasmic components and compartments. Sub-plastidic components such as thylakoids, stroma, the inner and outer membranes of the plastid envelope, nucleoids, plastoglobuli, and starch grains have been efficiently highlighted in living plant cells. In addition, stroma filled membrane extensions called stromules have drawn attention to the dynamic nature of the plastid and its interactions with the rest of the cell. Use of dual and triple fluorescent protein combinations has begun to reveal plastid interactions with mitochondria, the nucleus, the endoplasmic reticulum and F-actin and suggests integral roles of plastids in retrograde signaling, cell to cell communication as well as plant-pathogen interactions. While the rapid advances and insights achieved through fluorescent protein based research on plastids are commendable it is necessary to endorse meaningful observations but subject others to closer scrutiny. Here, in order to develop a better and more comprehensive understanding of plastids and their extensions we provide a critical appraisal of recent information that has been acquired using targeted fluorescent protein probes.
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37
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Bobik K, Burch-Smith TM. Chloroplast signaling within, between and beyond cells. FRONTIERS IN PLANT SCIENCE 2015; 6:781. [PMID: 26500659 PMCID: PMC4593955 DOI: 10.3389/fpls.2015.00781] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/10/2015] [Indexed: 05/18/2023]
Abstract
The most conspicuous function of plastids is the oxygenic photosynthesis of chloroplasts, yet plastids are super-factories that produce a plethora of compounds that are indispensable for proper plant physiology and development. Given their origins as free-living prokaryotes, it is not surprising that plastids possess their own genomes whose expression is essential to plastid function. This semi-autonomous character of plastids requires the existence of sophisticated regulatory mechanisms that provide reliable communication between them and other cellular compartments. Such intracellular signaling is necessary for coordinating whole-cell responses to constantly varying environmental cues and cellular metabolic needs. This is achieved by plastids acting as receivers and transmitters of specific signals that coordinate expression of the nuclear and plastid genomes according to particular needs. In this review we will consider the so-called retrograde signaling occurring between plastids and nuclei, and between plastids and other organelles. Another important role of the plastid we will discuss is the involvement of plastid signaling in biotic and abiotic stress that, in addition to influencing retrograde signaling, has direct effects on several cellular compartments including the cell wall. We will also review recent evidence pointing to an intriguing function of chloroplasts in regulating intercellular symplasmic transport. Finally, we consider an intriguing yet less widely known aspect of plant biology, chloroplast signaling from the perspective of the entire plant. Thus, accumulating evidence highlights that chloroplasts, with their complex signaling pathways, provide a mechanism for exquisite regulation of plant development, metabolism and responses to the environment. As chloroplast processes are targeted for engineering for improved productivity the effect of such modifications on chloroplast signaling will have to be carefully considered in order to avoid unintended consequences on plant growth and development.
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Affiliation(s)
| | - Tessa M. Burch-Smith
- *Correspondence: Tessa M. Burch-Smith, Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, 1414 Cumberland Avenue, M407 Walters Life Science, Knoxville, TN 37932, USA,
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38
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Schattat MH, Barton KA, Mathur J. The myth of interconnected plastids and related phenomena. PROTOPLASMA 2015; 252:359-71. [PMID: 24965372 DOI: 10.1007/s00709-014-0666-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 06/12/2014] [Indexed: 05/08/2023]
Abstract
Studies spread over nearly two and a half centuries have identified the primary plastid in autotrophic algae and plants as a pleomorphic, multifunctional organelle comprising of a double-membrane envelope enclosing an organization of internal membranes submerged in a watery stroma. All plastid units have been observed extending and retracting thin stroma-filled tubules named stromules sporadically. Observations on living plant cells often convey the impression that stromules connect two or more independent plastids with each other. When photo-bleaching techniques were used to suggest that macromolecules such as the green fluorescent protein could flow between already interconnected plastids, for many people this impression changed to conviction. However, it was noticed only recently that the concept of protein flow between plastids rests solely on the words "interconnected plastids" for which details have never been provided. We have critically reviewed botanical literature dating back to the 1880s for understanding this term and the phenomena that have become associated with it. We find that while meticulously detailed ontogenic studies spanning nearly 150 years have established the plastid as a singular unit organelle, there is no experimental support for the idea that interconnected plastids exist under normal conditions of growth and development. In this review, while we consider several possibilities that might allow a single elongated plastid to be misinterpreted as two or more interconnected plastids, our final conclusion is that the concept of direct protein flow between plastids is based on an unfounded assumption.
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Affiliation(s)
- Martin H Schattat
- Martin-Luther-Universität Halle-Wittenberg Pflanzenphysiologie, Weinbergweg 10, 06120, Halle (Saale), Germany,
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39
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Ibl V, Stoger E. Live Cell Imaging During Germination Reveals Dynamic Tubular Structures Derived from Protein Storage Vacuoles of Barley Aleurone Cells. PLANTS 2014; 3:442-57. [PMID: 27135513 PMCID: PMC4844346 DOI: 10.3390/plants3030442] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 08/20/2014] [Accepted: 08/21/2014] [Indexed: 01/09/2023]
Abstract
The germination of cereal seeds is a rapid developmental process in which the endomembrane system undergoes a series of dynamic morphological changes to mobilize storage compounds. The changing ultrastructure of protein storage vacuoles (PSVs) in the cells of the aleurone layer has been investigated in the past, but generally this involved inferences drawn from static pictures representing different developmental stages. We used live cell imaging in transgenic barley plants expressing a TIP3-GFP fusion protein as a fluorescent PSV marker to follow in real time the spatially and temporally regulated remodeling and reshaping of PSVs during germination. During late-stage germination, we observed thin, tubular structures extending from PSVs in an actin-dependent manner. No extensions were detected following the disruption of actin microfilaments, while microtubules did not appear to be involved in the process. The previously-undetected tubular PSV structures were characterized by complex movements, fusion events and a dynamic morphology. Their function during germination remains unknown, but might be related to the transport of solutes and metabolites.
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Affiliation(s)
- Verena Ibl
- Department for Applied Genetics and Cell Biology, Molecular Plant Physiology and Crop Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, Vienna 1190, Austria.
| | - Eva Stoger
- Department for Applied Genetics and Cell Biology, Molecular Plant Physiology and Crop Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, Vienna 1190, Austria.
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40
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Davis RW, Jones HD, Collins AM, Ricken JB, Sinclair MB, Timlin JA, Singh S. Label-free measurement of algal triacylglyceride production using fluorescence hyperspectral imaging. ALGAL RES 2014. [DOI: 10.1016/j.algal.2013.11.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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41
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Mueller SJ, Lang D, Hoernstein SN, Lang EG, Schuessele C, Schmidt A, Fluck M, Leisibach D, Niegl C, Zimmer AD, Schlosser A, Reski R. Quantitative analysis of the mitochondrial and plastid proteomes of the moss Physcomitrella patens reveals protein macrocompartmentation and microcompartmentation. PLANT PHYSIOLOGY 2014; 164:2081-95. [PMID: 24515833 PMCID: PMC3982764 DOI: 10.1104/pp.114.235754] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 02/07/2014] [Indexed: 05/22/2023]
Abstract
Extant eukaryotes are highly compartmentalized and have integrated endosymbionts as organelles, namely mitochondria and plastids in plants. During evolution, organellar proteomes are modified by gene gain and loss, by gene subfunctionalization and neofunctionalization, and by changes in protein targeting. To date, proteomics data for plastids and mitochondria are available for only a few plant model species, and evolutionary analyses of high-throughput data are scarce. We combined quantitative proteomics, cross-species comparative analysis of metabolic pathways, and localizations by fluorescent proteins in the model plant Physcomitrella patens in order to assess evolutionary changes in mitochondrial and plastid proteomes. This study implements data-mining methodology to classify and reliably reconstruct subcellular proteomes, to map metabolic pathways, and to study the effects of postendosymbiotic evolution on organellar pathway partitioning. Our results indicate that, although plant morphologies changed substantially during plant evolution, metabolic integration of organelles is largely conserved, with exceptions in amino acid and carbon metabolism. Retargeting or regulatory subfunctionalization are common in the studied nucleus-encoded gene families of organelle-targeted proteins. Moreover, complementing the proteomic analysis, fluorescent protein fusions revealed novel proteins at organelle interfaces such as plastid stromules (stroma-filled tubules) and highlight microcompartments as well as intercellular and intracellular heterogeneity of mitochondria and plastids. Thus, we establish a comprehensive data set for mitochondrial and plastid proteomes in moss, present a novel multilevel approach to organelle biology in plants, and place our findings into an evolutionary context.
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42
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Jarvis P, López-Juez E. Biogenesis and homeostasis of chloroplasts and other plastids. Nat Rev Mol Cell Biol 2014; 14:787-802. [PMID: 24263360 DOI: 10.1038/nrm3702] [Citation(s) in RCA: 403] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Chloroplasts are the organelles that define plants, and they are responsible for photosynthesis as well as numerous other functions. They are the ancestral members of a family of organelles known as plastids. Plastids are remarkably dynamic, existing in strikingly different forms that interconvert in response to developmental or environmental cues. The genetic system of this organelle and its coordination with the nucleocytosolic system, the import and routing of nucleus-encoded proteins, as well as organellar division all contribute to the biogenesis and homeostasis of plastids. They are controlled by the ubiquitin-proteasome system, which is part of a network of regulatory mechanisms that integrate plastid development into broader programmes of cellular and organismal development.
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Affiliation(s)
- Paul Jarvis
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
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Hanson MR, Sattarzadeh A. Fluorescent labeling and confocal microscopic imaging of chloroplasts and non-green plastids. Methods Mol Biol 2014; 1132:125-43. [PMID: 24599850 DOI: 10.1007/978-1-62703-995-6_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
While chlorophyll has served as an excellent label for plastids in green tissue, the development of fluorescent proteins has allowed their ready visualization in all tissues of the plants, revealing new features of their morphology and motility. Gene regulatory sequences in plastid transgenes can be optimized through the use of fluorescent protein reporters. Fluorescent labeling of plastids simultaneously with other subcellular locations reveals dynamic interactions and mutant phenotypes. Transient expression of fluorescent protein fusions is particularly valuable to determine whether or not a protein of unknown function is targeted to the plastid. Particle bombardment and agroinfiltration methods described here are convenient for imaging fluorescent proteins in plant organelles. With proper selection of fluorophores for labeling the components of the plant cell, confocal microscopy can produce extremely informative images at high resolution at depths not feasible by standard epifluorescence microscopy.
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Affiliation(s)
- Maureen R Hanson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
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Abstract
Plastid division is fundamental to the biology of plant cells. Division by binary fission entails the coordinated assembly and constriction of four concentric rings, two internal and two external to the organelle. The internal FtsZ ring and external dynamin-like ARC5/DRP5B ring are connected across the two envelopes by the membrane proteins ARC6, PARC6, PDV1, and PDV2. Assembly-stimulated GTPase activity drives constriction of the FtsZ and ARC5/DRP5B rings, which together with the plastid-dividing rings pull and squeeze the envelope membranes until the two daughter plastids are formed, with the final separation requiring additional proteins. The positioning of the division machinery is controlled by the chloroplast Min system, which confines FtsZ-ring formation to the plastid midpoint. The dynamic morphology of plastids, especially nongreen plastids, is also considered here, particularly in relation to the production of stromules and plastid-derived vesicles and their possible roles in cellular communication and plastid functionality.
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Abstract
Investigators studying G protein-coupled signaling--often called the best-understood pathway in the world owing to intense research in medical fields--have adopted plants as a new model to explore the plasticity and evolution of G signaling. Much research on plant G signaling has not disappointed. Although plant cells have most of the core elements found in animal G signaling, differences in network architecture and intrinsic properties of plant G protein elements make G signaling in plant cells distinct from the animal paradigm. In contrast to animal G proteins, plant G proteins are self-activating, and therefore regulation of G activation in plants occurs at the deactivation step. The self-activating property also means that plant G proteins do not need and therefore do not have typical animal G protein-coupled receptors. Targets of activated plant G proteins, also known as effectors, are unlike effectors in animal cells. The simpler repertoire of G signal elements in Arabidopsis makes G signaling easier to manipulate in a multicellular context.
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Affiliation(s)
- Daisuke Urano
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Alan M. Jones
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
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Ishida H, Izumi M, Wada S, Makino A. Roles of autophagy in chloroplast recycling. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:512-21. [PMID: 24269172 DOI: 10.1016/j.bbabio.2013.11.009] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 11/01/2013] [Accepted: 11/07/2013] [Indexed: 01/04/2023]
Abstract
Chloroplasts are the primary energy suppliers for plants, and much of the total leaf nitrogen is distributed to these organelles. During growth and reproduction, chloroplasts in turn represent a major source of nitrogen to be recovered from senescing leaves and used in newly-forming and storage organs. Chloroplast proteins also can be an alternative substrate for respiration under suboptimal conditions. Autophagy is a process of bulk degradation and nutrient sequestration that is conserved in all eukaryotes. Autophagy can selectively target chloroplasts as whole organelles and or as Rubisco-containing bodies that are enclosed by the envelope and specifically contain the stromal portion of the chloroplast. Although information is still limited, recent work indicates that chloroplast recycling via autophagy plays important roles not only in developmental processes but also in organelle quality control and adaptation to changing environments. This article is part of a Special Issue entitled: Dynamic and ultrastructure of bioenergetic membranes and their components.
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Affiliation(s)
- Hiroyuki Ishida
- Graduate School of Agricultural Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan.
| | - Masanori Izumi
- Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Shinya Wada
- Graduate School of Agricultural Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan
| | - Amane Makino
- Graduate School of Agricultural Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076, Japan
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Kaňa R. Mobility of photosynthetic proteins. PHOTOSYNTHESIS RESEARCH 2013; 116:465-79. [PMID: 23955784 DOI: 10.1007/s11120-013-9898-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 07/18/2013] [Indexed: 05/03/2023]
Abstract
The mobility of photosynthetic proteins represents an important factor that affects light-energy conversion in photosynthesis. The specific feature of photosynthetic proteins mobility can be currently measured in vivo using advanced microscopic methods, such as fluorescence recovery after photobleaching which allows the direct observation of photosynthetic proteins mobility on a single cell level. The heterogeneous organization of thylakoid membrane proteins results in heterogeneity in protein mobility. The thylakoid membrane contains both, protein-crowded compartments with immobile proteins and fluid areas (less crowded by proteins), allowing restricted diffusion of proteins. This heterogeneity represents an optimal balance as protein crowding is necessary for efficient light-energy conversion, and protein mobility plays an important role in the regulation of photosynthesis. The mobility is required for an optimal light-harvesting process (e.g., during state transitions), and also for transport of proteins during their synthesis or repair. Protein crowding is then a key limiting factor of thylakoid membrane protein mobility; the less thylakoid membranes are crowded by proteins, the higher protein mobility is observed. Mobility of photosynthetic proteins outside the thylakoid membrane (lumen and stroma/cytosol) is less understood. Cyanobacterial phycobilisomes attached to the stromal side of the thylakoid can move relatively fast. Therefore, it seems that stroma with their active enzymes of the Calvin-Benson cycle, are a more fluid compartment in comparison to the rather rigid thylakoid lumen. In conclusion, photosynthetic protein diffusion is generally slower in comparison to similarly sized proteins from other eukaryotic membranes or organelles. Mobility of photosynthetic proteins resembles restricted protein diffusion in bacteria, and has been rationalized by high protein crowding similar to that of thylakoids.
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Affiliation(s)
- Radek Kaňa
- Department of photothrophic microorganisms - Algatech, Institute of Microbiology, Academy of Sciences of the Czech Republic, Opatovický mlýn, 379 81, Třeboň, Czech Republic,
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Abstract
Stromules are thin projections from plastids that are generally longer and more abundant on non-green plastids than on chloroplasts. Occasionally stromules can be observed to connect two plastid bodies with one another. However, photobleaching of GFP-labeled plastids and stromules in 2000 demonstrated that plastids do not form a network like the endoplasmic reticulum, resulting in the proposal that stromules have major functions other than transfer of material from one plastid to another. The absence of a network was confirmed in 2012 with the use of a photoconvertible fluorescent protein, but the prior observations of movement of proteins between plastids were challenged. We review published evidence and provide new experiments that demonstrate trafficking of fluorescent protein between plastids as well as movement of proteins within stromules that emanate from a single plastid and discuss the possible function of stromules.
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Reitz MU, Pai S, Imani J, Schäfer P. New insights into the subcellular localization of Tubby-like proteins and their participation in the Arabidopsis-Piriformospora indica interaction. PLANT SIGNALING & BEHAVIOR 2013; 8:25198. [PMID: 23733076 PMCID: PMC3999060 DOI: 10.4161/psb.25198] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Tubby-like proteins (TLPs) have been associated with hormone signaling and responses to abiotic and biotic stress in plants. Recently, Arabidopsis thaliana TLP3 was found to translocate from the plasma membrane of cells in response to distinct abiotic stresses, thereby activating cellular signaling. In addition, several AtTLPs were demonstrated to be necessary for normal colonization of roots by the mutualistic fungus Piriformospora indica. Here, we present evidence for the involvement of another two AtTLPs in this interaction. Furthermore, we show that plasma membrane targeting of TLPs might be conserved in other plant species, although we did not find it for all members of the protein family. Finally, the position of a GFP-tag influences the localization of AtTLP3, which needs to be considered when working with TLPs.
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Affiliation(s)
- Marco U. Reitz
- The School of Life Sciences; University of Warwick; Gibbet Hill Campus; Coventry, UK
| | - Subhash Pai
- Institute of Phytopathology and Applied Zoology; Research Centre for Biosystems; Land Use
| | - Jafargholi Imani
- Institute of Phytopathology and Applied Zoology; Research Centre for Biosystems; Land Use
| | - Patrick Schäfer
- The School of Life Sciences; University of Warwick; Gibbet Hill Campus; Coventry, UK
- Correspondence to: Patrick Schäfer,
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Xing F, Li Z, Sun A, Xing D. Reactive oxygen species promote chloroplast dysfunction and salicylic acid accumulation in fumonisin B1-induced cell death. FEBS Lett 2013; 587:2164-72. [DOI: 10.1016/j.febslet.2013.05.034] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 04/19/2013] [Accepted: 05/05/2013] [Indexed: 12/22/2022]
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