1
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Rudinskiy M, Molinari M. ER-to-lysosome-associated degradation in a nutshell: mammalian, yeast, and plant ER-phagy as induced by misfolded proteins. FEBS Lett 2023; 597:1928-1945. [PMID: 37259628 DOI: 10.1002/1873-3468.14674] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 05/10/2023] [Accepted: 05/22/2023] [Indexed: 06/02/2023]
Abstract
Conserved catabolic pathways operate to remove aberrant polypeptides from the endoplasmic reticulum (ER), the major biosynthetic organelle of eukaryotic cells. The best known are the ER-associated degradation (ERAD) pathways that control the retrotranslocation of terminally misfolded proteins across the ER membrane for clearance by the cytoplasmic ubiquitin/proteasome system. In this review, we catalog folding-defective mammalian, yeast, and plant proteins that fail to engage ERAD machineries. We describe that they rather segregate in ER subdomains that eventually vesiculate. These ER-derived vesicles are captured by double membrane autophagosomes, engulfed by endolysosomes/vacuoles, or fused with degradative organelles to clear cells from their toxic cargo. These client-specific, mechanistically diverse ER-phagy pathways are grouped under the umbrella term of ER-to-lysosome-associated degradation for description in this essay.
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Affiliation(s)
- Mikhail Rudinskiy
- Università della Svizzera italiana, Lugano, Switzerland
- Institute for Research in Biomedicine, Bellinzona, Switzerland
- Department of Biology, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Maurizio Molinari
- Università della Svizzera italiana, Lugano, Switzerland
- Institute for Research in Biomedicine, Bellinzona, Switzerland
- School of Life Sciences, École Polytechnique Fédérale de Lausanne, Switzerland
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2
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The role of Atg16 in autophagy, anthocyanin biosynthesis, and programmed cell death in leaves of the lace plant (Aponogeton madagascariensis). PLoS One 2023; 18:e0281668. [PMID: 36795694 PMCID: PMC9934333 DOI: 10.1371/journal.pone.0281668] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 01/29/2023] [Indexed: 02/17/2023] Open
Abstract
Aponogeton madagascariensis, commonly known as the lace plant, produces leaves that form perforations by programmed cell death (PCD). Leaf development is divided into several stages beginning with "pre-perforation" furled leaves enriched with red pigmentation from anthocyanins. The leaf blade is characterized by a series of grids known as areoles bounded by veins. As leaves develop into the "window stage", anthocyanins recede from the center of the areole towards the vasculature creating a gradient of pigmentation and cell death. Cells in the middle of the areole that lack anthocyanins undergo PCD (PCD cells), while cells that retain anthocyanins (non-PCD cells) maintain homeostasis and persist in the mature leaf. Autophagy has reported roles in survival or PCD promotion across different plant cell types. However, the direct involvement of autophagy in PCD and anthocyanin levels during lace plant leaf development has not been determined. Previous RNA sequencing analysis revealed the upregulation of autophagy-related gene Atg16 transcripts in pre-perforation and window stage leaves, but how Atg16 affects PCD in lace plant leaf development is unknown. In this study, we investigated the levels of Atg16 in lace plant PCD by treating whole plants with either an autophagy promoter rapamycin or inhibitors concanamycin A (ConA) or wortmannin. Following treatments, window and mature stage leaves were harvested and analyzed using microscopy, spectrophotometry, and western blotting. Western blotting showed significantly higher Atg16 levels in rapamycin-treated window leaves, coupled with lower anthocyanin levels. Wortmannin-treated leaves had significantly lower Atg16 protein and higher anthocyanin levels compared to the control. Mature leaves from rapamycin-treated plants generated significantly fewer perforations compared to control, while wortmannin had the opposite effect. However, ConA treatment did not significantly change Atg16 levels, nor the number of perforations compared to the control, but anthocyanin levels did increase significantly in window leaves. We propose autophagy plays a dual role in promoting cell survival in NPCD cells by maintaining optimal anthocyanin levels and mediating a timely cell death in PCD cells in developing lace plant leaves. How autophagy specifically affects anthocyanin levels remained unexplained.
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3
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Xi J, Zeng J, Fu X, Zhang L, Li G, Li B, Yan X, Chu Q, Xiao Y, Pei Y, Zhang M. GhROP6 GTPase modulates auxin accumulation in cotton fibers by regulating cell-specific GhPIN3a localization. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:265-282. [PMID: 36255218 DOI: 10.1093/jxb/erac416] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
PIN-FORMED- (PIN) mediated polar auxin transport plays a predominant role in most auxin-triggered organogenesis in plants. Global control of PIN polarity at the plasma membrane contributes to the essential establishment of auxin maxima in most multicellular tissues. However, establishment of auxin maxima in single cells is poorly understood. Cotton fibers, derived from ovule epidermal cells by auxin-triggered cell protrusion, provide an ideal model to explore the underlying mechanism. Here, we report that cell-specific degradation of GhPIN3a, which guides the establishment of the auxin gradient in cotton ovule epidermal cells, is associated with the preferential expression of GhROP6 GTPase in fiber cells. In turn, GhROP6 reduces GhPIN3a abundance at the plasma membrane and facilitates intracellular proteolysis of GhPIN3a. Overexpression and activation of GhROP6 promote cell elongation, resulting in a substantial improvement in cotton fiber length.
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Affiliation(s)
- Jing Xi
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400715, PR China
- Academy of Agricultural Sciences, Southwest University, Chongqing, PR China
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Southwest University, Chongqing, PR China
| | - Jianyan Zeng
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400715, PR China
- Academy of Agricultural Sciences, Southwest University, Chongqing, PR China
| | - Xingxian Fu
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400715, PR China
- Academy of Agricultural Sciences, Southwest University, Chongqing, PR China
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Southwest University, Chongqing, PR China
| | - Liuqin Zhang
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400715, PR China
- Academy of Agricultural Sciences, Southwest University, Chongqing, PR China
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Southwest University, Chongqing, PR China
| | - Gailing Li
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400715, PR China
| | - Baoxia Li
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400715, PR China
- Academy of Agricultural Sciences, Southwest University, Chongqing, PR China
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Southwest University, Chongqing, PR China
| | - Xingying Yan
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400715, PR China
- Academy of Agricultural Sciences, Southwest University, Chongqing, PR China
| | - Qingqing Chu
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400715, PR China
- Academy of Agricultural Sciences, Southwest University, Chongqing, PR China
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Southwest University, Chongqing, PR China
| | - Yuehua Xiao
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400715, PR China
- Academy of Agricultural Sciences, Southwest University, Chongqing, PR China
| | - Yan Pei
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400715, PR China
- Academy of Agricultural Sciences, Southwest University, Chongqing, PR China
| | - Mi Zhang
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400715, PR China
- Academy of Agricultural Sciences, Southwest University, Chongqing, PR China
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Southwest University, Chongqing, PR China
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4
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Akar M, Ercin M, Boran T, Gezginci-Oktayoglu S, Özhan G. UR-144, synthetic cannabinoid receptor agonist, induced cardiomyoblast toxicity mechanism comprises cytoplasmic Ca 2+ and DAPK1 related autophagy and necrosis. Toxicol Mech Methods 2023; 33:56-64. [PMID: 35606921 DOI: 10.1080/15376516.2022.2081829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
UR-144, a cannabinoid receptor agonist, is widely used alone or in combination with other synthetic cannabinoids (SCs) all over the world. At overdose, cardiovascular symptoms have been reported and the underlying molecular mechanisms of these adverse effects are not known. It is highly important to clarify the toxic effects of UR-144 for the treatment of poisoning. In the present study, the molecular mechanism of cytotoxic effects of UR-144 is evaluated on a cardiomyoblastic cell line using WST-1 and LDH assays. Apoptosis/necrosis, autophagy, and ROS (reactive oxygen species) levels were determined using flow cytometry. Cytoplasmic Ca2+ levels were measured by using a fluorogenic calcium-binding dye. Released and cytoplasmic troponin T levels, a specific marker of cardiotoxicity, were examined with western blot. For the evaluation of the role of DAPK1, on UR-144-induced cell death, DAPK1 activity and DAPK1 protein level were investigated. Its cytotoxic effects increased in a dose-dependent manner for WST-1 and LDH assays, while membrane damage, one of the signs of necrotic cell death, was more remarkable than damage to mitochondria. Cytoplasmic Ca2+ levels rose after high-dose UR-144 treatment and inhibition of DAPK1 activity ameliorated UR-144-induced cytotoxicity. Released troponin T significantly increased at a dose of 200 µM. ROS and total antioxidant capacity of cells were both reduced following high dose UR-144 treatment. The results indicated that UR-144-induced autophagic and necrotic cell death might be a consequence of elevated cytoplasmic Ca2+ levels and DAPK1 activation. However, in vivo/clinical studies are needed to identify molecular mechanisms of cardiotoxic effects of UR-144.
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Affiliation(s)
- Muzeyyen Akar
- Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey
| | - Merve Ercin
- Department of Biology, Faculty of Science, Istanbul University, Istanbul, Turkey
| | - Tugce Boran
- Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey
| | | | - Gül Özhan
- Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey
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5
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Kacprzak SM, Van Aken O. Carbon starvation, senescence and specific mitochondrial stresses, but not nitrogen starvation and general stresses, are major triggers for mitophagy in Arabidopsis. Autophagy 2022; 18:2894-2912. [PMID: 35311445 PMCID: PMC9673927 DOI: 10.1080/15548627.2022.2054039] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Selective degradation of mitochondria by autophagy (mitophagy) is thought to play an important role in mitochondrial quality control, but our understanding of which conditions induce mitophagy in plants is limited. Here, we developed novel reporter lines to monitor mitophagy in plants and surveyed the rate of mitophagy under a wide range of stresses and developmental conditions. Especially carbon starvation induced by dark-incubation causes a dramatic increase in mitophagy within a few hours, further increasing as dark-induced senescence progresses. Natural senescence was also a strong trigger of mitophagy, peaking when leaf yellowing became prominent. In contrast, nitrogen starvation, a trigger of general autophagy, does not induce strong increases in mitophagy. Similarly, general stresses such as hydrogen peroxide, heat, UV-B and hypoxia did not appear to trigger substantial mitophagy in plants. Additionally, we exposed plants to inhibitors of the mitochondrial electron transport chain, mitochondrial translation and protein import. Although short-term treatments did not induce high mitophagy rates, longer term exposures to uncoupling agent and inhibitors of mitochondrial protein import/translation could clearly increase mitophagic flux. These findings could further be confirmed using confocal microscopy. To validate that mitophagy is mediated by the autophagy pathway, we showed that mitophagic flux is abolished or strongly decreased in atg5/AuTophaGy 5 and atg11 mutants, respectively. Finally, we observed high rates of mitophagy in etiolated seedlings, which remarkably was completely repressed within 6 h after light exposure. In conclusion, we propose that dark-induced carbon starvation, natural senescence and specific mitochondrial stresses are key triggers of mitophagy in plants.Abbreviations: AA: antimycin A; ATG: AuToPhagy related; ConA: concanamycin A; DIS: dark-induced senescence; Dox: doxycycline; FCCP: carbonyl cyanide-p-trifluoromethoxyphenylhydrazone; GFP: green fluorescent protein; IDH1: isocitrate dehydrogenase 1; MB: MitoBlock-6; Mito-GFP: transgenic Arabidopsis line expressing a mitochondrially targeted protein fused to GFP; mtETC: mitochondrial electron transport chain; OXPHOS: oxidative phosphorylation; PQC: protein quality control; TOM20: Translocase of Outer Membrane 20.
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Affiliation(s)
| | - Olivier Van Aken
- Department of Biology, Lund University, Lund, Sweden,CONTACT Olivier Van Aken Molecular Cell Biology, Department of Biology, Lund, Sweden
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6
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Chen W, Hu Z, Yu M, Zhu S, Xing J, Song L, Pu W, Yu F. A molecular link between autophagy and circadian rhythm in plants. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:1044-1058. [PMID: 35297190 DOI: 10.1111/jipb.13250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 03/16/2022] [Indexed: 06/14/2023]
Abstract
Extremely high or low autophagy levels disrupt plant survival under nutrient starvation. Recently, autophagy has been reported to display rhythms in animals. However, the mechanism of circadian regulation of autophagy is still unclear. Here, we observed that autophagy has a robust rhythm and that various autophagy-related genes (ATGs) are rhythmically expressed in Arabidopsis. Chromatin immunoprecipitation (ChIP) and dual-luciferase (LUC) analyses showed that the core oscillator gene TIMING OF CAB EXPRESSION 1 (TOC1) directly binds to the promoters of ATG (ATG1a, ATG2, and ATG8d) and negatively regulates autophagy activities under nutritional stress. Furthermore, autophagy defects might affect endogenous rhythms by reducing the rhythm amplitude of TOC1 and shortening the rhythm period of CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1). Autophagy is essential for the circadian clock pattern in seedling development and plant sensitivity to nutritional deficiencies. Taken together, our studies reveal a plant strategy in which the TOC1-ATG axis involved in autophagy-rhythm crosstalk to fine-tune the intensity of autophagy.
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Affiliation(s)
- Weijun Chen
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, 410082, China
| | - Zhaotun Hu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, 410082, China
- Key Laboratory of Research and Utilization of Ethnomedicinal Plant Resources of Hunan Province, School of Biological and Food Engineering, Huaihua College, Huaihua, 418008, China
| | - MengTing Yu
- Key Laboratory of Research and Utilization of Ethnomedicinal Plant Resources of Hunan Province, School of Biological and Food Engineering, Huaihua College, Huaihua, 418008, China
| | - Sirui Zhu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, 410082, China
| | - Junjie Xing
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, 410125, China
| | - Limei Song
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, 410082, China
| | - Wenxuan Pu
- Technology Center, China Tobacco Hunan Industrial Co., Ltd., Changsha, 410007, China
| | - Feng Yu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, and Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, 410082, China
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, 410125, China
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7
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Lenz RR, Louie KB, Søndreli KL, Galanie SS, Chen JG, Muchero W, Bowen BP, Northen TR, LeBoldus JM. Metabolomic Patterns of Septoria Canker Resistant and Susceptible Populus trichocarpa Genotypes 24 Hours Postinoculation. PHYTOPATHOLOGY 2021; 111:2052-2066. [PMID: 33881913 DOI: 10.1094/phyto-02-21-0053-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Sphaerulina musiva is an economically and ecologically important fungal pathogen that causes Septoria stem canker and leaf spot disease of Populus species. To bridge the gap between genetic markers and structural barriers previously found to be linked to Septoria canker disease resistance in poplar, we used hydrophilic interaction liquid chromatography and tandem mass spectrometry to identify and quantify metabolites involved with signaling and cell wall remodeling. Fluctuations in signaling molecules, organic acids, amino acids, sterols, phenolics, and saccharides in resistant and susceptible P. trichocarpa inoculated with S. musiva were observed. The patterns of 222 metabolites in the resistant host implicate systemic acquired resistance (SAR), cell wall apposition, and lignin deposition as modes of resistance to this hemibiotrophic pathogen. This pattern is consistent with the expected response to the biotrophic phase of S. musiva colonization during the first 24 h postinoculation. The fungal pathogen metabolized key regulatory signals of SAR, other phenolics, and precursors of lignin biosynthesis that were depleted in the susceptible host. This is the first study to characterize metabolites associated with the response to initial colonization by S. musiva between resistant and susceptible hosts.
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Affiliation(s)
- Ryan R Lenz
- Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
| | - Katherine B Louie
- Metabolomics Technology, DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Kelsey L Søndreli
- Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
| | | | - Jin-Gui Chen
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - Wellington Muchero
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - Benjamin P Bowen
- Metabolomics Technology, DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Trent R Northen
- Metabolomics Technology, DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Jared M LeBoldus
- Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
- Forest Resources, Engineering, and Management Department, Oregon State University, Corvallis, OR 97331
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8
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Goodson HV, Kelley JB, Brawley SH. Cytoskeletal diversification across 1 billion years: What red algae can teach us about the cytoskeleton, and vice versa. Bioessays 2021; 43:e2000278. [PMID: 33797088 DOI: 10.1002/bies.202000278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 11/05/2022]
Abstract
The cytoskeleton has a central role in eukaryotic biology, enabling cells to organize internally, polarize, and translocate. Studying cytoskeletal machinery across the tree of life can identify common elements, illuminate fundamental mechanisms, and provide insight into processes specific to less-characterized organisms. Red algae represent an ancient lineage that is diverse, ecologically significant, and biomedically relevant. Recent genomic analysis shows that red algae have a surprising paucity of cytoskeletal elements, particularly molecular motors. Here, we review the genomic and cell biological evidence and propose testable models of how red algal cells might perform processes including cell motility, cytokinesis, intracellular transport, and secretion, given their reduced cytoskeletons. In addition to enhancing understanding of red algae and lineages that evolved from red algal endosymbioses (e.g., apicomplexan parasites), these ideas may also provide insight into cytoskeletal processes in animal cells.
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Affiliation(s)
- Holly V Goodson
- Department of Chemistry and Biochemistry and Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Joshua B Kelley
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine, USA
| | - Susan H Brawley
- School of Marine Sciences, University of Maine, Orono, Maine, USA
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9
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Trujillo-Moya C, Ganthaler A, Stöggl W, Kranner I, Schüler S, Ertl R, Schlosser S, George JP, Mayr S. RNA-Seq and secondary metabolite analyses reveal a putative defence-transcriptome in Norway spruce (Picea abies) against needle bladder rust (Chrysomyxa rhododendri) infection. BMC Genomics 2020; 21:336. [PMID: 32357832 PMCID: PMC7195740 DOI: 10.1186/s12864-020-6587-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 02/18/2020] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Norway spruce trees in subalpine forests frequently face infections by the needle rust fungus Chrysomyxa rhododendri, which causes significant growth decline and increased mortality of young trees. Yet, it is unknown whether trees actively respond to fungal attack by activating molecular defence responses and/or respective gene expression. RESULTS Here, we report results from an infection experiment, in which the transcriptomes (via RNA-Seq analysis) and phenolic profiles (via UHPLC-MS) of control and infected trees were compared over a period of 39 days. Gene expression between infected and uninfected ramets significantly differed after 21 days of infection and revealed already known, but also novel candidate genes involved in spruce molecular defence against pathogens. CONCLUSIONS Combined RNA-Seq and biochemical data suggest that Norway spruce response to infection by C. rhododendri is restricted locally and primarily activated between 9 and 21 days after infestation, involving a potential isolation of the fungus by a hypersensitive response (HR) associated with an activation of phenolic pathways. Identified key regulatory genes represent a solid basis for further specific analyses in spruce varieties with varying susceptibility, to better characterise resistant clones and to elucidate the resistance mechanism.
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Affiliation(s)
- Carlos Trujillo-Moya
- Federal Research and Training Centre for Forests, Landscape and Natural Hazards (BFW)-Department of Forest Genetics, Seckendorff-Gudent-Weg 8, 1131 Vienna, Austria
| | - Andrea Ganthaler
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Wolfgang Stöggl
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Ilse Kranner
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Silvio Schüler
- Federal Research and Training Centre for Forests, Landscape and Natural Hazards (BFW)- Department of Forest Growth & Silviculture, Seckendorff-Gudent-Weg 8, 1131 Vienna, Austria
| | - Reinhard Ertl
- VetCore Facility for Research, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria
| | - Sarah Schlosser
- VetCore Facility for Research, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria
| | - Jan-Peter George
- Federal Research and Training Centre for Forests, Landscape and Natural Hazards (BFW)-Department of Forest Genetics, Seckendorff-Gudent-Weg 8, 1131 Vienna, Austria
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
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10
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Tarnowski L, Collados Rodriguez M, Brzywczy J, Cysewski D, Wawrzynska A, Sirko A. Overexpression of the Selective Autophagy Cargo Receptor NBR1 Modifies Plant Response to Sulfur Deficit. Cells 2020; 9:E669. [PMID: 32164165 PMCID: PMC7140714 DOI: 10.3390/cells9030669] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/03/2020] [Accepted: 03/06/2020] [Indexed: 12/21/2022] Open
Abstract
Plants exposed to sulfur deficit elevate the transcription of NBR1 what might reflect an increased demand for NBR1 in such conditions. Therefore, we investigated the role of this selective autophagy cargo receptor in plant response to sulfur deficit (-S). Transcriptome analysis of the wild type and NBR1 overexpressing plants pointed out differences in gene expression in response to -S. Our attention focused particularly on the genes upregulated by -S in roots of both lines because of significant overrepresentation of cytoplasmic ribosomal gene family. Moreover, we noticed overrepresentation of the same family in the set of proteins co-purifying with NBR1 in -S. One of these ribosomal proteins, RPS6 was chosen for verification of its direct interaction with NBR1 and proven to bind outside the NBR1 ubiquitin binding domains. The biological significance of this novel interaction and the postulated role of NBR1 in ribosomes remodeling in response to starvation remain to be further investigated. Interestingly, NBR1 overexpressing seedlings have significantly shorter roots than wild type when grown in nutrient deficient conditions in the presence of TOR kinase inhibitors. This phenotype probably results from excessive autophagy induction by the additive effect of NBR1 overexpression, starvation, and TOR inhibition.
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Affiliation(s)
- Leszek Tarnowski
- Department of Plant Biochemistry, Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawińskiego 5A St, 02-106 Warsaw, Poland
| | - Milagros Collados Rodriguez
- Department of Plant Biochemistry, Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawińskiego 5A St, 02-106 Warsaw, Poland
| | - Jerzy Brzywczy
- Department of Plant Biochemistry, Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawińskiego 5A St, 02-106 Warsaw, Poland
| | - Dominik Cysewski
- Laboratory of Mass Spectrometry, Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawińskiego 5A St, 02-106 Warsaw, Poland
| | - Anna Wawrzynska
- Department of Plant Biochemistry, Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawińskiego 5A St, 02-106 Warsaw, Poland
| | - Agnieszka Sirko
- Department of Plant Biochemistry, Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawińskiego 5A St, 02-106 Warsaw, Poland
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11
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Machado SR, Rodrigues TM. Autophagy and vacuolar biogenesis during the nectary development. PLANTA 2019; 250:519-533. [PMID: 31104130 DOI: 10.1007/s00425-019-03190-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/14/2019] [Indexed: 05/26/2023]
Abstract
Different autophagy pathways are a driver of vacuolar biogenesis and are development stage specific during the extrafloral nectary development in Citharexylum myrianthum. Plant autophagy plays an important role in various developmental processes such as seed germination, pollen maturation and leaf senescence. However, studies that address the evidence of autophagy and its role in the development of plant glands are scarce and largely restricted to laticifers. Regarding nectary, studies have repeatedly pointed to signs of degradation associated with the end of the secretory cycle, without exploring autophagy. Likewise, the relationship between autophagy and biogenesis of vacuoles remains an unexplored issue. In this study, using conventional and microwave fixation in association with ultracytochemical methods for transmission electron microscopy, we investigated the occurrence of autophagy and its implication in the differentiation of extrafloral nectary in Citharexylum myrianthum (Verbenaceae) under natural conditions, focusing on the vacuole biogenesis. We described a variety of vacuole types associated with the stage of nectary epidermis development, which differs with respect to origin, function and nature of the products to be stored. Three distinct autophagy pathways were detected: macroautophagy, microautophagy (both restricted to the undifferentiated epidermal cells, at the presecretory stage) and megaautophagy (circumscribed to the differentiated epidermal cells, at the postsecretory stage). Our study clearly demonstrated that the vacuole variety and autophagy processes in the nectary epidermal cells are development specific. This study highlights the role of autophagy in vacuole biogenesis and its implications for the development of nectary and opens new venues for future studies on regulation mechanisms for autophagy in plant secretory structures under normal conditions.
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Affiliation(s)
- Silvia R Machado
- Department of Botany, Institute of Biosciences of Botucatu (IBB), São Paulo State University (UNESP), Botucatu City, SP, Brazil.
- Center of Electron Microscopy (CME), Institute of Biosciences of Botucatu (IBB), São Paulo State University (UNESP), Botucatu City, SP, Brazil.
| | - Tatiane M Rodrigues
- Department of Botany, Institute of Biosciences of Botucatu (IBB), São Paulo State University (UNESP), Botucatu City, SP, Brazil
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12
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Sadhu A, Moriyasu Y, Acharya K, Bandyopadhyay M. Nitric oxide and ROS mediate autophagy and regulate Alternaria alternata toxin-induced cell death in tobacco BY-2 cells. Sci Rep 2019; 9:8973. [PMID: 31222105 PMCID: PMC6586778 DOI: 10.1038/s41598-019-45470-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 05/09/2019] [Indexed: 11/25/2022] Open
Abstract
Synergistic interaction of nitric oxide (NO) and reactive oxygen species (ROS) is essential to initiate cell death mechanisms in plants. Though autophagy is salient in either restricting or promoting hypersensitivity response (HR)-related cell death, the crosstalk between the reactive intermediates and autophagy during hypersensitivity response is paradoxical. In this investigation, the consequences of Alternaria alternata toxin (AaT) in tobacco BY-2 cells were examined. At 3 h, AaT perturbed intracellular ROS homeostasis, altered antioxidant enzyme activities, triggered mitochondrial depolarization and induced autophagy. Suppression of autophagy by 3-Methyladenine caused a decline in cell viability in AaT treated cells, which indicated the vital role of autophagy in cell survival. After 24 h, AaT facilitated Ca2+ influx with an accumulation of reactive oxidant intermediates and NO, to manifest necrotic cell death. Inhibition of NO accumulation by 2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) decreased the level of necrotic cell death, and induced autophagy, which suggests NO accumulation represses autophagy and facilitates necrotic cell death at 24 h. Application of N-acetyl-L-cysteine at 3 h, confirmed ROS to be the key initiator of autophagy, and together with cPTIO for 24 h, revealed the combined effects of NO and ROS is required for necrotic HR cell death.
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Affiliation(s)
- Abhishek Sadhu
- Plant Molecular Cytogenetics Laboratory, Centre of Advanced Study, Department of Botany, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, West Bengal, India
| | - Yuji Moriyasu
- Graduate School of Science and Engineering, Saitama University, Shimo-Okubo 255, Saitama, 338-8570, Japan
| | - Krishnendu Acharya
- Molecular and Applied Mycology and Plant Pathology Laboratory, Centre of Advanced Study, Department of Botany, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, West Bengal, India
| | - Maumita Bandyopadhyay
- Plant Molecular Cytogenetics Laboratory, Centre of Advanced Study, Department of Botany, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, West Bengal, India.
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13
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Dias BRS, de Souza CS, Almeida NDJ, Lima JGB, Fukutani KF, Dos Santos TBS, França-Cost J, Brodskyn CI, de Menezes JPB, Colombo MI, Veras PST. Autophagic Induction Greatly Enhances Leishmania major Intracellular Survival Compared to Leishmania amazonensis in CBA/j-Infected Macrophages. Front Microbiol 2018; 9:1890. [PMID: 30158914 PMCID: PMC6104192 DOI: 10.3389/fmicb.2018.01890] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 07/27/2018] [Indexed: 12/29/2022] Open
Abstract
CBA mouse macrophages control Leishmania major infection yet are permissive to Leishmania amazonensis. Few studies have been conducted to assess the role played by autophagy in Leishmania infection. Therefore, we assessed whether the autophagic response of infected macrophages may account for the differential behavior of these two parasite strains. After 24 h of infection, the LC3-II/Act ratio increased in both L. amazonensis- and L. major-infected macrophages compared to uninfected controls, but less than in chloroquine-treated cells. This suggests that L. amazonensis and L. major activate autophagy in infected macrophages, without altering the autophagic flux. Furthermore, L. major-infected cells exhibited higher percentages of DQ-BSA-labeled parasitophorous vacuoles (50%) than those infected by L. amazonensis (25%). However, L. major- and L. amazonensis-induced parasitophorous vacuoles accumulated LysoTracker similarly, indicating that the acidity in both compartment was equivalent. At as early as 30 min, endogenous LC3 was recruited to both L. amazonensis- and L. major-induced parasitophorous vacuoles, while after 24 h a greater percentage of LC3 positive vacuoles was observed in L. amazonensis-infected cells (42.36%) compared to those infected by L. major (18.10%). Noteworthy, principal component analysis (PCA) and an hierarchical cluster analysis completely discriminated L. major-infected macrophages from L. amazonensis-infected cells accordingly to infection intensity and autophagic features of parasite-induced vacuoles. Then, we evaluated whether the modulation of autophagy exerted an influence on parasite infection in macrophages. No significant changes were observed in both infection rate or parasite load in macrophages treated with the autophagic inhibitors wortmannin, chloroquine or VPS34-IN1, as well as with the autophagic inducers rapamycin or physiological starvation, in comparison to untreated control cells. Interestingly, both autophagic inducers enhanced intracellular L. amazonensis and L. major viability, while the pharmacological inhibition of autophagy exerted no effects on intracellular parasite viability. We also demonstrated that autophagy induction reduced NO production by L. amazonensis- and L. major-infected macrophages but not alters arginase activity. These findings provide evidence that although L. amazonensis-induced parasitophorous vacuoles recruit LC3 more markedly, L. amazonensis and L. major similarly activate the autophagic pathway in CBA macrophages. Interestingly, the exogenous induction of autophagy favors L. major intracellular viability to a greater extent than L. amazonensis related to a reduction in the levels of NO.
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Affiliation(s)
- Beatriz R S Dias
- Laboratory of Parasite-Host Interaction and Epidemiology, Gonçalo Moniz Institute, Salvador, Brazil
| | - Carina S de Souza
- Laboratory of Parasite-Host Interaction and Epidemiology, Gonçalo Moniz Institute, Salvador, Brazil
| | - Niara de Jesus Almeida
- Laboratory of Parasite-Host Interaction and Epidemiology, Gonçalo Moniz Institute, Salvador, Brazil
| | - José G B Lima
- Laboratory of Parasite-Host Interaction and Epidemiology, Gonçalo Moniz Institute, Salvador, Brazil
| | - Kiyoshi F Fukutani
- Laboratory of Inflammation and Biomarkers, Gonçalo Moniz Institute, Salvador, Brazil
| | - Thiale B S Dos Santos
- Laboratory of Inflammation and Biomarkers, Gonçalo Moniz Institute, Salvador, Brazil
| | - Jaqueline França-Cost
- Laboratory of Inflammation and Biomarkers, Gonçalo Moniz Institute, Salvador, Brazil.,Department of Biointeraction, Federal University of Bahia, Salvador, Brazil
| | - Claudia I Brodskyn
- Laboratory of Parasite-Host Interaction and Epidemiology, Gonçalo Moniz Institute, Salvador, Brazil
| | - Juliana P B de Menezes
- Laboratory of Parasite-Host Interaction and Epidemiology, Gonçalo Moniz Institute, Salvador, Brazil
| | - Maria I Colombo
- Laboratory of Cellular and Molecular Biology, Institute of Histology and Embryology-CONICET, National University of Cuyo, Mendoza, Argentina
| | - Patricia S T Veras
- Laboratory of Parasite-Host Interaction and Epidemiology, Gonçalo Moniz Institute, Salvador, Brazil
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14
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Mamun MAA, Tang C, Sun Y, Islam MN, Liu P, Wang X, Kang Z. Wheat Gene TaATG8j Contributes to Stripe Rust Resistance. Int J Mol Sci 2018; 19:ijms19061666. [PMID: 29874811 PMCID: PMC6032272 DOI: 10.3390/ijms19061666] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 05/30/2018] [Accepted: 06/01/2018] [Indexed: 11/16/2022] Open
Abstract
Autophagy-related 8 (ATG8) protein has been reported to be involved in plant’s innate immune response, but it is not clear whether such genes play a similar role in cereal crops against obligate biotrophic fungal pathogens. Here, we reported an ATG8 gene from wheat (Triticum aestivum), designated TaATG8j. This gene has three copies located in chromosomes 2AS, 2BS, and 2DS. The transcriptions of all three copies were upregulated in plants of the wheat cultivar Suwon 11, inoculated with an avirulent race (CYR23) of Puccinia striiformis f. sp. tritici (Pst), the causal fungal pathogen of stripe rust. The transient expression of TaATG8j in Nicotiana benthamiana showed that TaATG8j proteins were distributed throughout the cytoplasm, but mainly in the nucleus and plasma membrane. The overexpression of TaATG8j in N. benthamiana slightly delayed the cell death caused by the mouse apoptotic protein BAX (BCL2-associated X protein). However, the expression of TaATG8j in yeast (Schizosaccharomyces pombe) induced cell death. The virus-induced gene silencing of all TaATG8j copies rendered Suwon 11 susceptible to the avirulent Pst race CYR23, accompanied by an increased fungal biomass and a decreased necrotic area per infection site. These results indicate that TaATG8j contributes to wheat resistance against stripe rust fungus by regulating cell death, providing information for the understanding of the mechanisms of wheat resistance to the stripe rust pathogen.
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Affiliation(s)
- Md Abdullah-Al Mamun
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling 712100, China.
- Regional Wheat Research Centre, Bangladesh Agricultural Research Institute, Shyampur, Rajshahi-6212, Bangladesh.
| | - Chunlei Tang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling 712100, China.
| | - Yingchao Sun
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling 712100, China.
| | - Md Nazrul Islam
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling 712100, China.
- Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, Northwest A&F University, Yangling 712100, China.
- Agrochemical and Environmental Research Division, Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Bangladesh Atomic Energy Commission, Ganakbari, Savar, Dhaka-1349, Bangladesh.
| | - Peng Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling 712100, China.
| | - Xiaojie Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling 712100, China.
| | - Zhensheng Kang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling 712100, China.
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15
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Sadhu A, Ghosh I, Moriyasu Y, Mukherjee A, Bandyopadhyay M. Role of cerium oxide nanoparticle-induced autophagy as a safeguard to exogenous H2O2-mediated DNA damage in tobacco BY-2 cells. Mutagenesis 2018; 33:161-177. [PMID: 29506140 DOI: 10.1093/mutage/gey004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 02/10/2018] [Indexed: 12/17/2023] Open
Abstract
The effect of cerium oxide nanoparticle (CeNP) in plants has elicited substantial controversy. While some investigators have reported that CeNP possesses antioxidant properties, others observed CeNP to induce reactive oxygen species (ROS). In spite of considerable research carried out on the effects of CeNP in metazoans, fundamental studies that can unveil its intracellular consequences linking ROS production, autophagy and DNA damage are lacking in plants. To elucidate the impact of CeNP within plant cells, tobacco BY-2 cells were treated with 10, 50 and 250 µg ml-1 CeNP (Ce10, Ce50 and Ce250), for 24 h. Results demonstrated concentration-dependent accumulation of Ca2+ and ROS at all CeNP treatment sets. However, significant DNA damage and alteration in antioxidant defence systems were noted prominently at Ce50 and Ce250. Moreover, Ce50 and Ce250 induced DNA damage, analysed by comet assay and DNA diffusion experiments, complied with the concomitant increase in ROS. Furthermore, to evaluate the antioxidant property of CeNP, treated cells were washed after 24 h (to minimise CeNP interference) and challenged with H2O2 for 3 h. Ce10 did not induce genotoxicity and H2O2 exposure to Ce10-treated cells showed lesser DNA breakage than cells treated with H2O2 only. Interestingly, Ce10 provided better protection over N-acetyl-L-cysteine against exogenous H2O2 in BY-2 cells. CeNP exposure to transgenic BY-2 cells expressing GFP-Atg8 fusion protein exhibited formation of autophagosomes at Ce10. Application of vacuolar protease inhibitor E-64c and fluorescent basic dye acridine orange, further demonstrated accumulation of particulate matters in the vacuole and occurrence of acidic compartments, the autophagolysosomes, respectively. BY-2 cells co-treated with CeNP and autophagy inhibitor 3-methyladenine exhibited increased DNA damage in Ce10 and cell death at all assessed treatment sets. Thus, current results substantiate an alternative autophagy-mediated, antioxidant and geno-protective role of CeNP, which will aid in deciphering novel phenomena of plant-nanoparticle interaction at cellular level.
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Affiliation(s)
- Abhishek Sadhu
- Plant Molecular Cytogenetics Laboratory, Centre of Advanced Study, Department of Botany, University of Calcutta, Kolkata, West Bengal, India
| | - Ilika Ghosh
- Cell Biology and Genetic Toxicology Laboratory, Centre of Advanced Study, Department of Botany, University of Calcutta, Ballygunge Circular Road, Kolkata, India
| | - Yuji Moriyasu
- Graduate School of Science and Engineering, Saitama University, Shimo-Okubo, Saitama, Japan
| | - Anita Mukherjee
- Cell Biology and Genetic Toxicology Laboratory, Centre of Advanced Study, Department of Botany, University of Calcutta, Ballygunge Circular Road, Kolkata, India
| | - Maumita Bandyopadhyay
- Plant Molecular Cytogenetics Laboratory, Centre of Advanced Study, Department of Botany, University of Calcutta, Kolkata, West Bengal, India
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16
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Zhang Q, Wang D, Zhang H, Wang M, Li P, Fang X, Cai X. Detection of autophagy processes during the development of nonarticulated laticifers in Euphorbia kansui Liou. PLANTA 2018; 247:845-861. [PMID: 29260395 DOI: 10.1007/s00425-017-2835-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 12/15/2017] [Indexed: 06/07/2023]
Abstract
Autophagy is involved in cytoplasmic degradation through directly engulfing cytosol and organelles by autophagosomes and then fusing with lysosome-like vesicles during the development of nonarticulated laticifers in Euphorbia kansui Liou. Autophagy has been reported to play an important role in a wide range of eukaryotic organisms during responses to various abiotic and biotic stresses. However, until recently, the functions of autophagy in normal plant differentiation and development were still in their infancy. Nonarticulated laticifers, a type of secretory tissue in plants, undergo the degradation of cytosol and organelles during their development. However, little evidence of autophagy in laticifer differentiation has been provided. In the present study, using anti-ATG8 antibody-Alexa Fluor 488, Lyso-Tracker Red (LTR) and monodansylcadaverine (MDC) as markers for detecting autophagosomes, as well as autophagy-related structures, we observed that the green fluorescence of ATG8a largely colocalized with the red fluorescence of LTR and purple fluorescence of MDC and the quantity of autophagosomes experienced a trend from less to more to less during laticifer development. Additionally, we described the autophagy process during the development of nonarticulated laticifers in Euphorbia kansui Liou at the ultrastructural level in detail. In addition, further immunogold TEM studies also verified the presence of autophagosomes, autolysosomes and lysosome-like structures in laticifers. Taken together, these results suggest that autophagy contributes to the development of the nonarticulated laticifers in E. kansui Liou and that autophagosomes fuse with lysosome-like structures for degradation. These results will lay an important foundation for further studies on laticifer regulation.
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Affiliation(s)
- Qing Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Dou Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Hao Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Meng Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Peng Li
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Xiaoai Fang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China
| | - Xia Cai
- Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, 710069, China.
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17
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Xu G, Wang S, Han S, Xie K, Wang Y, Li J, Liu Y. Plant Bax Inhibitor-1 interacts with ATG6 to regulate autophagy and programmed cell death. Autophagy 2017; 13:1161-1175. [PMID: 28537463 PMCID: PMC5529081 DOI: 10.1080/15548627.2017.1320633] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Autophagy is an evolutionarily conserved catabolic process and is involved in the regulation of programmed cell death during the plant immune response. However, mechanisms regulating autophagy and cell death are incompletely understood. Here, we demonstrate that plant Bax inhibitor-1 (BI-1), a highly conserved cell death regulator, interacts with ATG6, a core autophagy-related protein. Silencing of BI-1 reduced the autophagic activity induced by both N gene-mediated resistance to Tobacco mosaic virus (TMV) and methyl viologen (MV), and enhanced N gene-mediated cell death. In contrast, overexpression of plant BI-1 increased autophagic activity and surprisingly caused autophagy-dependent cell death. These results suggest that plant BI-1 has both prosurvival and prodeath effects in different physiological contexts and both depend on autophagic activity.
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Affiliation(s)
- Guoyong Xu
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China,Department of Biology, Duke University, Durham, NC, USA
| | - Shanshan Wang
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Shaojie Han
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China,Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA
| | - Ke Xie
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China,School of Chemistry and Biological Engineering, University of Science and Technology, Beijing, China
| | - Yan Wang
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jinlin Li
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yule Liu
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China,CONTACT Yule Liu School of Life Sciences, Tsinghua University, Beijing 100084, China
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18
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Bao Y, Mugume Y, Bassham DC. Biochemical Methods to Monitor Autophagic Responses in Plants. Methods Enzymol 2016; 588:497-513. [PMID: 28237117 DOI: 10.1016/bs.mie.2016.09.090] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The study of autophagy in plants is rapidly increasing, due to its pivotal and fundamental roles in responding to stressful stimuli, recycling nutrients during senescence, and maintaining growth under normal conditions. Assays for detecting autophagy in plants have generally been based on microscopic observations, providing qualitative information on autophagy activity. Here, we discuss biochemical assays for detecting autophagy, which have the potential for providing more quantitative information, with a focus on immunoblotting with antibodies against ATG8, NBR1, or epitope tags fused to ATG proteins.
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Affiliation(s)
- Y Bao
- Iowa State University, Ames, IA, United States
| | - Y Mugume
- Iowa State University, Ames, IA, United States
| | - D C Bassham
- Iowa State University, Ames, IA, United States.
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19
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Han S, Wang Y, Zheng X, Jia Q, Zhao J, Bai F, Hong Y, Liu Y. Cytoplastic Glyceraldehyde-3-Phosphate Dehydrogenases Interact with ATG3 to Negatively Regulate Autophagy and Immunity in Nicotiana benthamiana. THE PLANT CELL 2015; 27:1316-31. [PMID: 25829441 PMCID: PMC4558687 DOI: 10.1105/tpc.114.134692] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 03/03/2015] [Accepted: 03/13/2015] [Indexed: 05/17/2023]
Abstract
Autophagy as a conserved catabolic pathway can respond to reactive oxygen species (ROS) and plays an important role in degrading oxidized proteins in plants under various stress conditions. However, how ROS regulates autophagy in response to oxidative stresses is largely unknown. Here, we show that autophagy-related protein 3 (ATG3) interacts with the cytosolic glyceraldehyde-3-phosphate dehydrogenases (GAPCs) to regulate autophagy in Nicotiana benthamiana plants. We found that oxidative stress inhibits the interaction of ATG3 with GAPCs. Silencing of GAPCs significantly activates ATG3-dependent autophagy, while overexpression of GAPCs suppresses autophagy in N. benthamiana plants. Moreover, silencing of GAPCs enhances N gene-mediated cell death and plant resistance against both incompatible pathogens Tobacco mosaic virus and Pseudomonas syringae pv tomato DC3000, as well as compatible pathogen P. syringae pv tabaci. These results indicate that GAPCs have multiple functions in the regulation of autophagy, hypersensitive response, and plant innate immunity.
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Affiliation(s)
- Shaojie Han
- Center for Plant Biology and MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yan Wang
- Center for Plant Biology and MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiyin Zheng
- Center for Plant Biology and MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qi Jia
- Center for Plant Biology and MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jinping Zhao
- Center for Plant Biology and MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Fan Bai
- Center for Plant Biology and MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yiguo Hong
- Research Centre for Plant RNA Signaling, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
| | - Yule Liu
- Center for Plant Biology and MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
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20
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Øverby A, Stokland RA, Åsberg SE, Sporsheim B, Bones AM. Allyl isothiocyanate depletes glutathione and upregulates expression of glutathione S-transferases in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2015; 6:277. [PMID: 25954298 PMCID: PMC4406002 DOI: 10.3389/fpls.2015.00277] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/07/2015] [Indexed: 05/08/2023]
Abstract
Allyl isothiocyanate (AITC) is a phytochemical associated with plant defense in plants from the Brassicaceae family. AITC has long been recognized as a countermeasure against external threats, but recent reports suggest that AITC is also involved in the onset of defense-related mechanisms such as the regulation of stomatal aperture. However, the underlying cellular modes of action in plants remain scarcely investigated. Here we report evidence of an AITC-induced depletion of glutathione (GSH) and the effect on gene expression of the detoxification enzyme family glutathione S-transferases (GSTs) in Arabidopsis thaliana. Treatment of A. thaliana wild-type with AITC resulted in a time- and dose-dependent depletion of cellular GSH. AITC-exposure of mutant lines vtc1 and pad2-1 with elevated and reduced GSH-levels, displayed enhanced and decreased AITC-tolerance, respectively. AITC-exposure also led to increased ROS-levels in the roots and loss of chlorophyll which are symptoms of oxidative stress. Following exposure to AITC, we found that GSH rapidly recovered to the same level as in the control plant, suggesting an effective route for replenishment of GSH or a rapid detoxification of AITC. Transcriptional analysis of genes encoding GSTs showed an upregulation in response to AITC. These findings demonstrate cellular effects by AITC involving a reversible depletion of the GSH-pool, induced oxidative stress, and elevated expression of GST-encoding genes.
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Affiliation(s)
- Anders Øverby
- *Correspondence: Anders Øverby and Atle M. Bones, Department of Biology, Norwegian University of Science and Technology, Høgskoleringen 5, N-7491 Trondheim, Norway ;
| | | | | | | | - Atle M. Bones
- *Correspondence: Anders Øverby and Atle M. Bones, Department of Biology, Norwegian University of Science and Technology, Høgskoleringen 5, N-7491 Trondheim, Norway ;
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21
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Pei D, Zhang W, Sun H, Wei X, Yue J, Wang H. Identification of autophagy-related genes ATG4 and ATG8 from wheat (Triticum aestivum L.) and profiling of their expression patterns responding to biotic and abiotic stresses. PLANT CELL REPORTS 2014; 33:1697-710. [PMID: 24996626 DOI: 10.1007/s00299-014-1648-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 06/09/2014] [Accepted: 06/13/2014] [Indexed: 05/02/2023]
Abstract
The genes coding for wheat ATG4 and ATG8 were cloned and their roles in autophagy were verified. Implications of ATG4/ATG8 in wheat responses to stresses were suggested by expression profiling. Autophagy-related proteins ATG4 and ATG8 are crucial for autophagy biogenesis. ATG4 processes ATG8 precursor to expose its C-terminal glycine for phosphatidyl ethanolamine (PE) lipidation. ATG8, in the form of ATG8-PE adduct, functions in the organization dynamics of autophagic membranes. Here, we report the identification of two/nine members of the ATG4/ATG8 family from common wheat (Triticum aestivum L.). Expression of each wheat ATG4/ATG8 could complement the autophagy activity of yeast atg4/atg8 mutant cells. GFP fusion proteins of ATG8s, especially of ATG8s with innate C-terminal-exposed glycines, localized to punctate autophagic membranes. Both of purified ATG4s could cleave ATG8s in vitro, but they had different activities and different preferences for ATG8 substrates. Two times of transcript accumulation, an early one and a late one, of ATG4s/ATG8s were detected in the early phases of the Pm21- and Pm3f-triggered wheat incompatible reactions to the powdery mildew causal fungus Blumeria graminis f. sp. tritici (Bgt), and fluorescence microscopy also revealed a Bgt-induced enhanced wheat autophagy level in the Pm21-triggered incompatible reaction. Only one time of Bgt-induced transcript accumulation of ATG4s/ATG8s, corresponding to but much higher than the late one in incompatible reactions, was detected in a susceptible line isogenic to the Pm21 resistance line. These results suggested positive roles of ATG4/ATG8-associated autophagy process in the early stage and possible negative roles in the late stage of wheat immunity response to Bgt. In addition, expression of wheat ATG4s/ATG8s was also found to be upregulated by abiotic stress factors and distinctively regulated by different phytohormones.
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Affiliation(s)
- Dan Pei
- School of Life Sciences, Tianjin Normal University, Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin, 300387, China,
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Hanamata S, Kurusu T, Okada M, Suda A, Kawamura K, Tsukada E, Kuchitsu K. In vivo imaging and quantitative monitoring of autophagic flux in tobacco BY-2 cells. PLANT SIGNALING & BEHAVIOR 2013; 8:e22510. [PMID: 23123450 PMCID: PMC3745557 DOI: 10.4161/psb.22510] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 10/10/2012] [Accepted: 10/10/2012] [Indexed: 05/18/2023]
Abstract
Autophagy has been shown to play essential roles in the growth, development and survival of eukaryotic cells. However, simple methods for quantification and visualization of autophagic flux remain to be developed in living plant cells. Here, we analyzed the autophagic flux in transgenic tobacco BY-2 cell lines expressing fluorescence-tagged NtATG8a as a marker for autophagosome formation. Under sucrose-starved conditions, the number of punctate signals of YFP-NtATG8a increased, and the fluorescence intensity of the cytoplasm and nucleoplasm decreased. Conversely, these changes were not observed in BY-2 cells expressing a C-terminal glycine deletion mutant of the NtATG8a protein (NtATG8aΔG). To monitor the autophagic flux more easily, we generated a transgenic BY-2 cell line expressing NtATG8a fused to a pH-sensitive fluorescent tag, a tandem fusion of the acid-insensitive RFP and the acid-sensitive YFP. In sucrose-rich conditions, both fluorescent signals were detected in the cytoplasm and only weakly in the vacuole. In contrast, under sucrose-starved conditions, the fluorescence intensity of the cytoplasm decreased, and the RFP signal clearly increased in the vacuole, corresponding to the fusion of the autophagosome to the vacuole and translocation of ATG8 from the cytoplasm to the vacuole. Moreover, we introduce a novel simple easy way to monitor the autophagic flux non-invasively by only measuring the ratio of fluorescence of RFP and YFP in the cell suspension using a fluorescent image analyzer without microscopy. The present in vivo quantitative monitoring system for the autophagic flux offers a powerful tool for determining the physiological functions and molecular mechanisms of plant autophagy induced by environmental stimuli.
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Affiliation(s)
- Shigeru Hanamata
- Department of Applied Biological Science; Tokyo University of Science; Noda, Chiba, Japan
| | - Takamitsu Kurusu
- Department of Applied Biological Science; Tokyo University of Science; Noda, Chiba, Japan
- Research Institute for Science and Technology; Tokyo University of Science; Noda, Chiba, Japan
| | - Masaaki Okada
- Department of Applied Biological Science; Tokyo University of Science; Noda, Chiba, Japan
| | - Akiko Suda
- Department of Applied Biological Science; Tokyo University of Science; Noda, Chiba, Japan
| | - Koki Kawamura
- Department of Applied Biological Science; Tokyo University of Science; Noda, Chiba, Japan
| | - Emi Tsukada
- Department of Applied Biological Science; Tokyo University of Science; Noda, Chiba, Japan
| | - Kazuyuki Kuchitsu
- Department of Applied Biological Science; Tokyo University of Science; Noda, Chiba, Japan
- Research Institute for Science and Technology; Tokyo University of Science; Noda, Chiba, Japan
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23
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Kim SH, Kwon C, Lee JH, Chung T. Genes for plant autophagy: functions and interactions. Mol Cells 2012; 34:413-23. [PMID: 22772908 PMCID: PMC3887786 DOI: 10.1007/s10059-012-0098-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 05/22/2012] [Accepted: 05/23/2012] [Indexed: 12/21/2022] Open
Abstract
Autophagy, or self-consuming of cytoplasmic constituents in a lytic compartment, plays a crucial role in nutrient recycling, development, cell homeostasis, and defense against pathogens and toxic products. Autophagy in plant cells uses a conserved machinery of core Autophagy-related (Atg) proteins. Recently, research on plant autophagy has been expanding and other components interacting with the core Atg proteins are being revealed. In addition, growing evidence suggests that autophagy communicates with other cellular pathways such as the ubiquitin-proteasome system, protein secretory pathway, and endocytic pathway. An increase in our understanding of plant autophagy will undoubtedly help test the hypothesized functions of plant autophagy in programmed cell death, vacuole biogenesis, and responses to biotic, abiotic, and nutritional stresses. In this review, we summarize recent progress on these topics and suggest topics for future research, after inspecting common phenotypes of current Arabidopsis atg mutants.
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Affiliation(s)
- Soon-Hee Kim
- Department of Biological Sciences, Pusan National University, Busan 609-735,
Korea
| | | | | | - Taijoon Chung
- Department of Biological Sciences, Pusan National University, Busan 609-735,
Korea
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24
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Akpinar BA, Avsar B, Lucas SJ, Budak H. Plant abiotic stress signaling. PLANT SIGNALING & BEHAVIOR 2012; 7:1450-5. [PMID: 22990453 PMCID: PMC3548870 DOI: 10.4161/psb.21894] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Stress signaling is central to plants which--as immobile organisms--have to endure environmental fluctuations that constantly interfere with vigorous growth. As a result, plant-specific, elaborate mechanisms have evolved to perceive and respond to stress conditions. Currently, these stress responses are plausibly being revealed to involve crosstalks with energy signaling pathways as any growth-limiting factor alters plant's energy status. Among these, autophagy, conventionally regarded as the mechanism whereby plants recycle and remobilize nutrients in bulk, has frequently been associated with stress responses. With the recent discoveries, however, autophagy has attained a novel role in stress signaling. In this review, major elements of abitoic stress signaling are summarized along with autophagy pathway, and in the light of recent discoveries, a putative, state-of-art role of autophagy is discussed.
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25
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Kuzuoglu-Ozturk D, Cebeci Yalcinkaya O, Akpinar BA, Mitou G, Korkmaz G, Gozuacik D, Budak H. Autophagy-related gene, TdAtg8, in wild emmer wheat plays a role in drought and osmotic stress response. PLANTA 2012; 236:1081-92. [PMID: 22569921 DOI: 10.1007/s00425-012-1657-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Accepted: 04/16/2012] [Indexed: 05/02/2023]
Abstract
An autophagy-related gene Atg8 was cloned for the first time from wild emmer wheat, named as TdAtg8, and its role on autophagy under abiotic stress conditions was investigated. Examination of TdAtg8 expression patterns indicated that Atg8 expression was strongly upregulated under drought stress, especially in the roots when compared to leaves. LysoTracker(®) red marker, utilized to observe autophagosomes, revealed that autophagy is constitutively active in Triticum dicoccoides. Moreover, autophagy was determined to be induced in plants exposed to osmotic stress when compared to plants grown under normal conditions. Functional studies were executed in yeast to confirm that the TdATG8 protein is functional, and showed that the TdAtg8 gene complements the atg8∆::kan MX yeast mutant strain grown under nitrogen deficiency. For further functional analysis, TdATG8 protein was expressed in yeast and analyzed using Western immunoblotting. Atg8-silenced plants were exposed to drought stress and chlorophyll and malondialdehyde (MDA) content measurements demonstrated that Atg8 plays a key role on drought stress tolerance. In addition, Atg8-silenced plants exposed to osmotic stress were found to have decreased Atg8 expression level in comparison to controls. Hence, Atg8 is a positive regulator in osmotic and drought stress response.
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Affiliation(s)
- Duygu Kuzuoglu-Ozturk
- Biological Sciences and Bioengineering Program, Sabanci University, Tuzla, Istanbul, Turkey
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26
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Different degree in proteasome malfunction has various effects on root growth possibly through preventing cell division and promoting autophagic vacuolization. PLoS One 2012; 7:e45673. [PMID: 23029176 PMCID: PMC3448697 DOI: 10.1371/journal.pone.0045673] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 08/20/2012] [Indexed: 01/07/2023] Open
Abstract
The ubiquitin/proteasome pathway plays a vital role in plant development. But the effects of proteasome malfunction on root growth, and the mechanism underlying this involvement remains unclear. In the present study, the effects of proteasome inhibitors on Arabidopsis root growth were studied through the analysis of the root length, and meristem size and cell length in maturation zone using FM4-64, and cell-division potential using GFP fusion cyclin B, and accumulation of ubiquitinated proteins using immunofluorescence labeling, and autophagy activity using LysoTracker and MDC. The results indicated that lower concentration of proteasome inhibitors promoted root growth, whereas higher concentration of inhibitors had the opposite effects. The accumulation of cyclin B was linked to MG132-induced decline in meristem size, indicating that proteasome malfunction prevented cell division. Besides, MG132-induced accumulation of the ubiquitinated proteins was associated with the increasing fluorescence signal of LysoTracker and MDC in the elongation zone, revealing a link between the activation of autophagy and proteasome malfunction. These results suggest that weak proteasome malfunction activates moderate autophagy and promotes cell elongation, which compensates the inhibitor-induced reduction of cell division, resulting in long roots. Whereas strong proteasome malfunction induces severe autophagy and disturbs cell elongation, resulting in short roots.
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27
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Cyrino LT, Araújo AP, Joazeiro PP, Vicente CP, Giorgio S. In vivo and in vitro Leishmania amazonensis infection induces autophagy in macrophages. Tissue Cell 2012; 44:401-8. [PMID: 22939777 DOI: 10.1016/j.tice.2012.08.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/13/2012] [Accepted: 08/02/2012] [Indexed: 12/19/2022]
Abstract
Autophagy is the primary mechanism of degradation of cellular proteins and at least two functions can be attributed to this biological phenomenon: increased nutrient supply via recycling of the products of autophagy under nutrient starvation; and antimicrobial response involved in the innate immune system. Many microorganisms induce host cell autophagy and it has been proposed as a pathway by which parasites compete with the host cell for limited resources. In this report we provide evidence that the intracellular parasite Leishmania amazonensis induces autophagy in macrophages. Using western blotting, the LC3II protein, a marker of autophagosomes, was detected in cell cultures with a high infection index. Macrophages infected with L. amazonensis were examined by transmission electronic microscopy, which revealed enlarged myelin-like structures typical late autophagosome and autolysosome. Other evidence indicating autophagy was Lysotracker red dye uptake by the macrophages. Autophagy also occurs in the leishmaniasis skin lesions of BALB/c mice, detected by immunohistochemistry with anti-LC3II antibody. In this study, autophagy inhibitor 3-methyladenine (3MA) reduced the infection index, while autophagy inductors, such as rapamycin or starvation, did not alter the infection index in cultivated macrophages, suggesting that one aspect of the role of autophagy could be the provision of nutritive support to the parasite.
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Affiliation(s)
- Larissa Tavares Cyrino
- Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Caixa Postal 6109, Cep 13.083-970, Campinas, São Paulo, Brazil
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28
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Guiboileau A, Masclaux-Daubresse C. L’autophagie chez les plantes : mécanismes, régulations et fonctions. C R Biol 2012; 335:375-88. [DOI: 10.1016/j.crvi.2012.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/13/2012] [Accepted: 04/14/2012] [Indexed: 12/20/2022]
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29
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Zientara-Rytter K, Lukomska J, Moniuszko G, Gwozdecki R, Surowiecki P, Lewandowska M, Liszewska F, Wawrzyńska A, Sirko A. Identification and functional analysis of Joka2, a tobacco member of the family of selective autophagy cargo receptors. Autophagy 2011; 7:1145-58. [PMID: 21670587 PMCID: PMC3242614 DOI: 10.4161/auto.7.10.16617] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 05/26/2011] [Accepted: 05/27/2011] [Indexed: 12/27/2022] Open
Abstract
Two main mechanisms of protein turnover exist in eukaryotic cells: the ubiquitin-proteasome system and the autophagy-lysosomal pathway. Autophagy is an emerging important constituent of many physiological and pathological processes, such as response to nutrient deficiency, programmed cell death and innate immune response. In mammalian cells the selectivity of autophagy is ensured by the presence of cargo receptors, such as p62/SQSTM1 and NBR1, responsible for sequestration of the ubiquitinated proteins. In plants no selective cargo receptors have been identified yet. The present report indicates that structural and functional homologs of p62 and NBR1 proteins exist in plants. The tobacco protein, named Joka2, has been identified in yeast two-hybrid search as a binding partner of a small coiled-coil protein, a member of UP9/LSU family of unknown function, encoded by the UP9C gene strongly and specifically induced during sulfur deficiency. The typical domains of p62 and NBR1 are conserved in Joka2. Similarly to p62, Joka2-YFP has dual localization (cytosolic speckles and the nucleus); it forms homodimers and interacts with a member of the ATG8 family. Increased expression of Joka2 and ATG8f was observed in roots of tobacco plants grown for two days in nutrient-deficient conditions. Constitutive ectopic expression of Joka2-YFP in tobacco resulted in attenuated response (manifested by lesser yellowing of the leaves) to nutrient deficiency. In conclusion, Joka2, and presumably the process of selective autophagy, might constitute an important part of plant response to environmental stresses.
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