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Ma J, Chen J, Wang M, Ren Y, Wang S, Lei C, Cheng Z. Disruption of OsSEC3A increases the content of salicylic acid and induces plant defense responses in rice. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1051-1064. [PMID: 29300985 PMCID: PMC6018903 DOI: 10.1093/jxb/erx458] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 12/13/2017] [Indexed: 05/19/2023]
Abstract
The exocyst, an evolutionarily conserved octameric protein complex involved in exocytosis, has been reported to be involved in diverse aspects of morphogenesis in Arabidopsis. However, the molecular functions of such exocytotic molecules in rice are poorly understood. Here, we examined the molecular function of OsSEC3A, an important subunit of the exocyst complex in rice. The OsSEC3A gene is expressed in various organs, and OsSEC3A has the potential ability to participate in the exocyst complex by interacting with several other exocyst subunits. Disruption of OsSEC3A by CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) caused dwarf stature and a lesion-mimic phenotype. The Ossec3a mutant exhibited enhanced defense responses, as shown by up-regulated transcript levels of pathogenesis- and salicylic acid synthesis-related genes, increased levels of salicylic acid, and enhanced resistance to the fungal pathogen Magnaporthe oryzae. Subcellular localization analysis demonstrated that OsSEC3A has a punctate distribution with the plasma membrane. In addition, OsSEC3A interacted with rice SNAP25-type t-SNARE protein OsSNAP32, which is involved in rice blast resistance, via the C-terminus and bound to phosphatidylinositol lipids, particularly phosphatidylinositol-3-phosphate, through its N-terminus. These findings uncover the novel function of rice exocyst subunit SEC3 in defense responses.
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Affiliation(s)
- Jin Ma
- Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing, China
| | - Jun Chen
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Min Wang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yulong Ren
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shuai Wang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Cailin Lei
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhijun Cheng
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
- Correspondence: and
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Khorramdelazad M, Bar I, Whatmore P, Smetham G, Bhaaskaria V, Yang Y, Bai SH, Mantri N, Zhou Y, Ford R. Transcriptome profiling of lentil (Lens culinaris) through the first 24 hours of Ascochyta lentis infection reveals key defence response genes. BMC Genomics 2018; 19:108. [PMID: 29385986 PMCID: PMC5793396 DOI: 10.1186/s12864-018-4488-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 01/17/2018] [Indexed: 09/14/2023] Open
Abstract
Background Ascochyta blight, caused by the fungus Ascochyta lentis, is one of the most destructive lentil diseases worldwide, resulting in over $16 million AUD annual loss in Australia alone. The use of resistant cultivars is currently considered the most effective and environmentally sustainable strategy to control this disease. However, little is known about the genes and molecular mechanisms underlying lentil resistance against A. lentis. Results To uncover the genetic basis of lentil resistance to A. lentis, differentially expressed genes were profiled in lentil plants during the early stages of A. lentis infection. The resistant ‘ILL7537’ and susceptible ‘ILL6002’ lentil genotypes were examined at 2, 6, and 24 h post inoculation utilising high throughput RNA-Sequencing. Genotype and time-dependent differential expression analysis identified genes which play key roles in several functions of the defence response: fungal elicitors recognition and early signalling; structural response; biochemical response; transcription regulators; hypersensitive reaction and cell death; and systemic acquired resistance. Overall, the resistant genotype displayed an earlier and faster detection and signalling response to the A. lentis infection and demonstrated higher expression levels of structural defence-related genes. Conclusions This study presents a first-time defence-related transcriptome of lentil to A. lentis, including a comprehensive characterisation of the molecular mechanism through which defence against A. lentis is induced in the resistant lentil genotype. Electronic supplementary material The online version of this article (10.1186/s12864-018-4488-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mahsa Khorramdelazad
- Glycomics institute, School of Sciences, Griffith University, 58 Parklands Dr., Southport, Gold Coast, 4215, QLD, Australia
| | - Ido Bar
- Environmental Futures Research Institute, School of Natural Sciences, Griffith University, 170 Kessels Rd., Nathan, 4111, QLD, Australia.
| | - Paul Whatmore
- Environmental Futures Research Institute, School of Natural Sciences, Griffith University, 170 Kessels Rd., Nathan, 4111, QLD, Australia.,Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, 4558, Queensland, Australia
| | - Gabrielle Smetham
- Fish Nutrition and Feed Safety, the National Institute of Nutrition and Seafood Research (NIFES), Strandgaten 229, Bergen, 5002, Norway
| | - Vijay Bhaaskaria
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 142 University St., Parkville, 3053, VIC, Australia
| | - Yuedong Yang
- Pangenomics Group, School of Sciences, RMIT University, Bundoora, 3083, VIC, Australia
| | - Shahla Hosseini Bai
- Glycomics institute, School of Sciences, Griffith University, 58 Parklands Dr., Southport, Gold Coast, 4215, QLD, Australia
| | - Nitin Mantri
- Environmental Futures Research Institute, School of Natural Sciences, Griffith University, 170 Kessels Rd., Nathan, 4111, QLD, Australia.,Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, 4558, Queensland, Australia
| | - Yaoqi Zhou
- Pangenomics Group, School of Sciences, RMIT University, Bundoora, 3083, VIC, Australia
| | - Rebecca Ford
- Glycomics institute, School of Sciences, Griffith University, 58 Parklands Dr., Southport, Gold Coast, 4215, QLD, Australia
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53
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Lampugnani ER, Khan GA, Somssich M, Persson S. Building a plant cell wall at a glance. J Cell Sci 2018; 131:131/2/jcs207373. [PMID: 29378834 DOI: 10.1242/jcs.207373] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Plant cells are surrounded by a strong polysaccharide-rich cell wall that aids in determining the overall form, growth and development of the plant body. Indeed, the unique shapes of the 40-odd cell types in plants are determined by their walls, as removal of the cell wall results in spherical protoplasts that are amorphic. Hence, assembly and remodeling of the wall is essential in plant development. Most plant cell walls are composed of a framework of cellulose microfibrils that are cross-linked to each other by heteropolysaccharides. The cell walls are highly dynamic and adapt to the changing requirements of the plant during growth. However, despite the importance of plant cell walls for plant growth and for applications that we use in our daily life such as food, feed and fuel, comparatively little is known about how they are synthesized and modified. In this Cell Science at a Glance article and accompanying poster, we aim to illustrate the underpinning cell biology of the synthesis of wall carbohydrates, and their incorporation into the wall, in the model plant Arabidopsis.
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Affiliation(s)
- Edwin R Lampugnani
- School of Biosciences, University of Melbourne, Parkville 3010 VIC, Melbourne, Australia
| | - Ghazanfar Abbas Khan
- School of Biosciences, University of Melbourne, Parkville 3010 VIC, Melbourne, Australia
| | - Marc Somssich
- School of Biosciences, University of Melbourne, Parkville 3010 VIC, Melbourne, Australia
| | - Staffan Persson
- School of Biosciences, University of Melbourne, Parkville 3010 VIC, Melbourne, Australia
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54
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Du Y, Overdijk EJR, Berg JA, Govers F, Bouwmeester K. Solanaceous exocyst subunits are involved in immunity to diverse plant pathogens. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:655-666. [PMID: 29329405 PMCID: PMC5853398 DOI: 10.1093/jxb/erx442] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 12/04/2017] [Indexed: 05/28/2023]
Abstract
The exocyst, a multiprotein complex consisting of eight subunits, plays an essential role in many biological processes by mediating secretion of post-Golgi-derived vesicles towards the plasma membrane. In recent years, roles for plant exocyst subunits in pathogen defence have been uncovered, largely based on studies in the model plant Arabidopsis. Only a few studies have been undertaken to assign the role of exocyst subunits in plant defence in other plants species, including crops. In this study, predicted protein sequences from exocyst subunits were retrieved by mining databases from the Solanaceous plants Nicotiana benthamiana, tomato, and potato. Subsequently, their evolutionary relationship with Arabidopsis exocyst subunits was analysed. Gene silencing in N. benthamiana showed that several exocyst subunits are required for proper plant defence against the (hemi-)biotrophic plant pathogens Phytophthora infestans and Pseudomonas syringae. In contrast, some exocyst subunits seem to act as susceptibility factors for the necrotrophic pathogen Botrytis cinerea. Furthermore, the majority of the exocyst subunits were found to be involved in callose deposition, suggesting that they play a role in basal plant defence. This study provides insight into the evolution of exocyst subunits in Solanaceous plants and is the first to show their role in immunity against multiple unrelated pathogens.
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Affiliation(s)
- Yu Du
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China
- Laboratory of Phytopathology, Wageningen University & Research, Wageningen, The Netherlands
| | - Elysa J R Overdijk
- Laboratory of Phytopathology, Wageningen University & Research, Wageningen, The Netherlands
- Laboratory of Cell Biology, Wageningen University & Research, Wageningen, The Netherlands
| | - Jeroen A Berg
- Laboratory of Phytopathology, Wageningen University & Research, Wageningen, The Netherlands
| | - Francine Govers
- Laboratory of Phytopathology, Wageningen University & Research, Wageningen, The Netherlands
| | - Klaas Bouwmeester
- Laboratory of Phytopathology, Wageningen University & Research, Wageningen, The Netherlands
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55
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Trujillo M. News from the PUB: plant U-box type E3 ubiquitin ligases. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:371-384. [PMID: 29237060 DOI: 10.1093/jxb/erx411] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 10/25/2017] [Indexed: 05/05/2023]
Abstract
Plant U-box type E3 ubiquitin ligases (PUBs) are well known for their functions in a variety of stress responses, including immune responses and the adaptation to abiotic stresses. First linked to pollen self-incompatibility, their repertoire of roles has grown to encompass also the regulation of developmental processes. Notably, new studies provide clues to their mode of action, underline the existence of conserved PUB-kinase modules, and suggest new links to G-protein signalling, placing PUBs at the crossroads of major signalling hubs. The frequent association with membranes, by interacting and/or targeting membrane proteins, as well as through a recently reported direct interaction with phospholipids, indicates a general function in the control of vesicle transport and their cargoes. This review aims to give an overview of the most significant advances in the field, while also trying to identify common themes of PUB function.
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Affiliation(s)
- Marco Trujillo
- Independent Junior Research Group-Ubiquitination in Immunity, Leibniz Institute of Plant Biochemistry, Germany
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56
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Verbančič J, Lunn JE, Stitt M, Persson S. Carbon Supply and the Regulation of Cell Wall Synthesis. MOLECULAR PLANT 2018; 11:75-94. [PMID: 29054565 DOI: 10.1016/j.molp.2017.10.004] [Citation(s) in RCA: 122] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 10/04/2017] [Accepted: 10/05/2017] [Indexed: 05/23/2023]
Abstract
All plant cells are surrounded by a cell wall that determines the directionality of cell growth and protects the cell against its environment. Plant cell walls are comprised primarily of polysaccharides and represent the largest sink for photosynthetically fixed carbon, both for individual plants and in the terrestrial biosphere as a whole. Cell wall synthesis is a highly sophisticated process, involving multiple enzymes and metabolic intermediates, intracellular trafficking of proteins and cell wall precursors, assembly of cell wall polymers into the extracellular matrix, remodeling of polymers and their interactions, and recycling of cell wall sugars. In this review we discuss how newly fixed carbon, in the form of UDP-glucose and other nucleotide sugars, contributes to the synthesis of cell wall polysaccharides, and how cell wall synthesis is influenced by the carbon status of the plant, with a focus on the model species Arabidopsis (Arabidopsis thaliana).
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Affiliation(s)
- Jana Verbančič
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany; School of Biosciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - John Edward Lunn
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany.
| | - Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Staffan Persson
- School of Biosciences, University of Melbourne, Parkville, VIC 3010, Australia.
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57
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Pecenková T, Markovic V, Sabol P, Kulich I, Žárský V. Exocyst and autophagy-related membrane trafficking in plants. JOURNAL OF EXPERIMENTAL BOTANY 2017; 69:47-57. [PMID: 29069430 DOI: 10.1093/jxb/erx363] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Endomembrane traffic in eukaryotic cells functions partially as a means of communication; delivery of membrane in one direction has to be balanced with a reduction at the other end. This effect is typically the case during the defence against pathogens. To combat pathogens, cellular growth and differentiation are suppressed, while endomembrane traffic is poised towards limiting the pathogen attack. The octameric exocyst vesicle-tethering complex was originally discovered as a factor facilitating vesicle-targeting and vesicle-plasma membrane (PM) fusion during exocytosis prior to and possibly during SNARE complex formation. Interestingly, it was recently implicated both in animals and plants in autophagy membrane traffic. In animal cells, the exocyst is integrated into the mTOR-regulated energy metabolism stress/starvation pathway, participating in the formation and especially initiation of an autophagosome. In plants, the first functional link was to autophagy-related anthocyanin import to the vacuole and to starvation. In this concise review, we summarize the current knowledge of exocyst functions in autophagy and defence in plants that might involve unconventional secretion and compare it with animal conditions. Formation of different exocyst complexes during undisturbed cell growth, as opposed to periods of cellular stress reactions involving autophagy, might contribute to the coordination of endomembrane trafficking pathways.
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Affiliation(s)
- Tamara Pecenková
- Laboratory of Cell Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Czech Republic
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Charles University in Prague, Faculty of Science, Czech Republic
| | - Vedrana Markovic
- Laboratory of Cell Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Czech Republic
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Charles University in Prague, Faculty of Science, Czech Republic
| | - Peter Sabol
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Charles University in Prague, Faculty of Science, Czech Republic
| | - Ivan Kulich
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Charles University in Prague, Faculty of Science, Czech Republic
| | - Viktor Žárský
- Laboratory of Cell Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Czech Republic
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Charles University in Prague, Faculty of Science, Czech Republic
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58
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Hansen LL, Nielsen ME. Plant exosomes: using an unconventional exit to prevent pathogen entry? JOURNAL OF EXPERIMENTAL BOTANY 2017; 69:59-68. [PMID: 29036447 DOI: 10.1093/jxb/erx319] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The ability to ward off filamentous pathogens, such as powdery mildew fungi, is one of the best studied examples of membrane trafficking-dependent disease resistance in plants. Here, papilla formation at the site of attack is essential for the pre-invasive immunity, whereas the encasement can hamper disease post-invasively. Exosomes containing antifungal peptides and small RNAs are thought to play a vital role in forming papillae and encasements that block fungal growth. While exosomes are well described in mammals, and have been shown to play important roles in cell-cell communication regulating development and disease, their function is not well-known in plants. In this review, we focus on some of the recent discoveries on plant exosomes and try to link this information with our current understanding of how plants use this form of unconventional secretion to acquire this durable and effective form of resistance.
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Affiliation(s)
- Line Lykke Hansen
- Department of Plant and Environmental Sciences, Copenhagen Plant Science Center (CPSC), University of Copenhagen, Denmark
| | - Mads Eggert Nielsen
- Department of Plant and Environmental Sciences, Copenhagen Plant Science Center (CPSC), University of Copenhagen, Denmark
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59
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Aljaafri WAR, McNeece BT, Lawaju BR, Sharma K, Niruala PM, Pant SR, Long DH, Lawrence KS, Lawrence GW, Klink VP. A harpin elicitor induces the expression of a coiled-coil nucleotide binding leucine rich repeat (CC-NB-LRR) defense signaling gene and others functioning during defense to parasitic nematodes. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 121:161-175. [PMID: 29107936 DOI: 10.1016/j.plaphy.2017.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/06/2017] [Accepted: 10/09/2017] [Indexed: 05/23/2023]
Abstract
The bacterial effector harpin induces the transcription of the Arabidopsis thaliana NON-RACE SPECIFIC DISEASE RESISTANCE 1/HARPIN INDUCED1 (NDR1/HIN1) coiled-coil nucleotide binding leucine rich repeat (CC-NB-LRR) defense signaling gene. In Glycine max, Gm-NDR1-1 transcripts have been detected within root cells undergoing a natural resistant reaction to parasitism by the syncytium-forming nematode Heterodera glycines, functioning in the defense response. Expressing Gm-NDR1-1 in Gossypium hirsutum leads to resistance to Meloidogyne incognita parasitism. In experiments presented here, the heterologous expression of Gm-NDR1-1 in G. hirsutum impairs Rotylenchulus reniformis parasitism. These results are consistent with the hypothesis that Gm-NDR1-1 expression functions broadly in generating a defense response. To examine a possible relationship with harpin, G. max plants topically treated with harpin result in induction of the transcription of Gm-NDR1-1. The result indicates the topical treatment of plants with harpin, itself, may lead to impaired nematode parasitism. Topical harpin treatments are shown to impair G. max parasitism by H. glycines, M. incognita and R. reniformis and G. hirsutum parasitism by M. incognita and R. reniformis. How harpin could function in defense has been examined in experiments showing it also induces transcription of G. max homologs of the proven defense genes ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1), TGA2, galactinol synthase, reticuline oxidase, xyloglucan endotransglycosylase/hydrolase, alpha soluble N-ethylmaleimide-sensitive fusion protein (α-SNAP) and serine hydroxymethyltransferase (SHMT). In contrast, other defense genes are not directly transcriptionally activated by harpin. The results indicate harpin induces pathogen associated molecular pattern (PAMP) triggered immunity (PTI) and effector-triggered immunity (ETI) defense processes in the root, activating defense to parasitic nematodes.
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Affiliation(s)
- Weasam A R Aljaafri
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, United States.
| | - Brant T McNeece
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, United States.
| | - Bisho R Lawaju
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, United States.
| | - Keshav Sharma
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, United States.
| | - Prakash M Niruala
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, United States.
| | - Shankar R Pant
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, United States.
| | - David H Long
- Albaugh, LLC, 4060 Dawkins Farm Drive, Olive Branch, MS 38654, United States.
| | - Kathy S Lawrence
- Department of Entomology and Plant Pathology, Auburn University, 209 Life Science Building, Auburn, AL 36849, United States.
| | - Gary W Lawrence
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, United States.
| | - Vincent P Klink
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, United States.
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60
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Ravikumar R, Steiner A, Assaad FF. Multisubunit tethering complexes in higher plants. CURRENT OPINION IN PLANT BIOLOGY 2017; 40:97-105. [PMID: 28889036 DOI: 10.1016/j.pbi.2017.08.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 07/21/2017] [Accepted: 08/18/2017] [Indexed: 05/23/2023]
Abstract
Tethering complexes mediate the initial, specific contact between donor and acceptor membranes. This review focuses on the modularity and function of multisubunit tethering complexes (MTCs) in higher plants. One emphasis is on molecular interactions of plant MTCs. Here, a number of insights have been gained concerning interactions between different tethering complexes, and between tethers and microtubule-associated proteins. The roles of tethering complexes in abiotic stress responses appear indirect, but in the context of biotic stress responses it has been suggested that some tethers are direct targets of pathogen effectors or virulence factors. In light of the central roles tethering complexes play in plant development, an emerging concept is that tethers may be co-opted for plant adaptive responses.
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Affiliation(s)
| | | | - Farhah F Assaad
- Botany, Technische Universität München, 85354 Freising, Germany.
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61
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Wang Y, Hu Q, Wu Z, Wang H, Han S, Jin Y, Zhou J, Zhang Z, Jiang J, Shen Y, Shi H, Yang W. HISTONE DEACETYLASE 6 represses pathogen defence responses in Arabidopsis thaliana. PLANT, CELL & ENVIRONMENT 2017; 40:2972-2986. [PMID: 28770584 DOI: 10.1111/pce.13047] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 07/23/2017] [Indexed: 05/18/2023]
Abstract
Plant defence mechanisms are suppressed in the absence of pathogen attack to prevent wasted energy and growth inhibition. However, how defence responses are repressed is not well understood. Histone deacetylase 6 (HDA6) is a negative regulator of gene expression, and its role in pathogen defence response in plants is not known. In this study, a novel allele of hda6 (designated as shi5) with spontaneous defence response was isolated from a forward genetics screening in Arabidopsis. The shi5 mutant exhibited increased resistance to hemibiotrophic bacterial pathogen Pst DC3000, constitutively activated expression of pathogen-responsive genes including PR1, PR2, etc. and increased histone acetylation levels at the promoters of most tested genes that were upregulated in shi5. In both wild type and shi5 plants, the expression and histone acetylation of these genes were upregulated by pathogen infection. HDA6 was found to bind to the promoters of these genes under both normal growth conditions and pathogen infection. Our research suggests that HDA6 is a general repressor of pathogen defence response and plays important roles in inhibiting and modulating the expression of pathogen-responsive genes in Arabidopsis.
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Affiliation(s)
- Yizhong Wang
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| | - Qin Hu
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| | - Zhenjiang Wu
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| | - Hui Wang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA
| | - Shiming Han
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| | - Ye Jin
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| | - Jin Zhou
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| | - Zhengfeng Zhang
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| | - Jiafu Jiang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA
| | - Yun Shen
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA
| | - Huazhong Shi
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA
| | - Wannian Yang
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
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62
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Liu H, Ravichandran S, Teh OK, McVey S, Lilley C, Teresinski HJ, Gonzalez-Ferrer C, Mullen RT, Hofius D, Prithiviraj B, Stone SL. The RING-Type E3 Ligase XBAT35.2 Is Involved in Cell Death Induction and Pathogen Response. PLANT PHYSIOLOGY 2017; 175:1469-1483. [PMID: 28951488 PMCID: PMC5664480 DOI: 10.1104/pp.17.01071] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 09/23/2017] [Indexed: 05/08/2023]
Abstract
XBAT35 belongs to a subfamily of Arabidopsis (Arabidopsis thaliana) RING-type E3s that are similar in domain architecture to the rice (Oryza sativa) XA21 Binding Protein3, a defense protein. The XBAT35 transcript undergoes alternative splicing to produce two protein isoforms, XBAT35.1 and XBAT35.2. Here, we demonstrate that XBAT35.2 localizes predominantly to the Golgi and is involved in cell death induction and pathogen response. XBAT35.2, but not XBAT35.1, was found to trigger cell death when overexpressed in tobacco (Nicotiana benthamiana) leaves and does so in a manner that requires its RING domain. Loss of XBAT35 gene function disrupts the plant's ability to defend against pathogen attack, whereas overexpression of XBAT35.2 enhances resistance to pathogens. XBAT35.2 was found to be unstable and promotes its own degradation, suggesting self-regulation. Inoculation with virulent and avirulent strains of the bacterial pathogen Pseudomonas syringae pv tomato DC3000 results in a drastic reduction in the levels of ubiquitinated XBAT35.2 and an increase in the abundance of the E3. This implies that pathogen infection prohibits XBAT35.2 self-regulation and stabilizes the E3. In agreement with a role in defending against pathogens, XBAT35.2 interacts with defense-related Accelerated Cell Death11 (ACD11) in planta and promotes the proteasome-dependent turnover of ACD11 in cell-free degradation assays. In accordance with regulation by a stabilized XBAT35.2, the levels of ubiquitinated ACD11 increased considerably, and the abundance of ACD11 was reduced following pathogen infection. In addition, treatment of transgenic seedlings with a proteasome inhibitor results in the accumulation of ACD11, confirming proteasome-dependent degradation. Collectively, these results highlight a novel role for XBAT35.2 in cell death induction and defense against pathogens.
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Affiliation(s)
- Hongxia Liu
- Biology Department, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4R4
| | - Sridhar Ravichandran
- Department of Plant, Food, and Environmental Sciences, Agricultural Campus, Dalhousie University, Truro, Nova Scotia, Canada B2N 5E3
| | - Ooi-Kock Teh
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences (SLU) and Linnean Center for Plant Biology, SE-75007 Uppsala, Sweden
| | - Sarah McVey
- Biology Department, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4R4
| | - Carly Lilley
- Biology Department, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4R4
| | - Howard J Teresinski
- Department of Molecular and Cellular Biology, Summerlee Science Complex, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | | | - Robert T Mullen
- Department of Molecular and Cellular Biology, Summerlee Science Complex, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Daniel Hofius
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences (SLU) and Linnean Center for Plant Biology, SE-75007 Uppsala, Sweden
| | - Balakrishnan Prithiviraj
- Department of Plant, Food, and Environmental Sciences, Agricultural Campus, Dalhousie University, Truro, Nova Scotia, Canada B2N 5E3
| | - Sophia L Stone
- Biology Department, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4R4
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Pečenková T, Janda M, Ortmannová J, Hajná V, Stehlíková Z, Žárský V. Early Arabidopsis root hair growth stimulation by pathogenic strains of Pseudomonas syringae. ANNALS OF BOTANY 2017; 120:437-446. [PMID: 28911019 PMCID: PMC5591418 DOI: 10.1093/aob/mcx073] [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: 11/09/2016] [Revised: 04/20/2017] [Indexed: 05/20/2023]
Abstract
BACKGROUND AND AIMS Selected beneficial Pseudomonas spp. strains have the ability to influence root architecture in Arabidopsis thaliana by inhibiting primary root elongation and promoting lateral root and root hair formation. A crucial role for auxin in this long-term (1week), long-distance plant-microbe interaction has been demonstrated. METHODS Arabidopsis seedlings were cultivated in vitro on vertical plates and inoculated with pathogenic strains Pseudomonas syringae pv. maculicola (Psm) and P. syringae pv. tomato DC3000 (Pst), as well as Agrobacterium tumefaciens (Atu) and Escherichia coli (Eco). Root hair lengths were measured after 24 and 48h of direct exposure to each bacterial strain. Several Arabidopsis mutants with impaired responses to pathogens, impaired ethylene perception and defects in the exocyst vesicle tethering complex that is involved in secretion were also analysed. KEY RESULTS Arabidopsis seedling roots infected with Psm or Pst responded similarly to when infected with plant growth-promoting rhizobacteria; root hair growth was stimulated and primary root growth was inhibited. Other plant- and soil-adapted bacteria induced similar root hair responses. The most compromised root hair growth stimulation response was found for the knockout mutants exo70A1 and ein2. The single immune pathways dependent on salicylic acid, jasmonic acid and PAD4 are not directly involved in root hair growth stimulation; however, in the mutual cross-talk with ethylene, they indirectly modify the extent of the stimulation of root hair growth. The Flg22 peptide does not initiate root hair stimulation as intact bacteria do, but pretreatment with Flg22 prior to Psm inoculation abolished root hair growth stimulation in an FLS2 receptor kinase-dependent manner. These early response phenomena are not associated with changes in auxin levels, as monitored with the pDR5::GUS auxin reporter. CONCLUSIONS Early stimulation of root hair growth is an effect of an unidentified component of living plant pathogenic bacteria. The root hair growth response is triggered in the range of hours after bacterial contact with roots and can be modulated by FLS2 signalling. Bacterial stimulation of root hair growth requires functional ethylene signalling and an efficient exocyst-dependent secretory machinery.
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Affiliation(s)
- Tamara Pečenková
- Laboratory of Cell Biology, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 263, 165 02, Prague 6, Czech Republic
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Vinicna 5, 128 44 Prague 2, Czech Republic
- For correspondence. E-mail
| | - Martin Janda
- Laboratory of Pathological Plant Physiology
- Laboratory of Plant Biochemistry, Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technicka 5, 166 28 Prague 6, Czech Republic
| | - Jitka Ortmannová
- Laboratory of Cell Biology, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 263, 165 02, Prague 6, Czech Republic
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Vinicna 5, 128 44 Prague 2, Czech Republic
| | - Vladimíra Hajná
- Laboratory of Signal Transduction, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 263, 165 02 Prague 6, Czech Republic
- Laboratory of Plant Biochemistry, Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technicka 5, 166 28 Prague 6, Czech Republic
| | - Zuzana Stehlíková
- Laboratory of Pathological Plant Physiology
- Laboratory of Plant Biochemistry, Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technicka 5, 166 28 Prague 6, Czech Republic
| | - Viktor Žárský
- Laboratory of Cell Biology, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 263, 165 02, Prague 6, Czech Republic
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Vinicna 5, 128 44 Prague 2, Czech Republic
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64
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Gu Y, Zavaliev R, Dong X. Membrane Trafficking in Plant Immunity. MOLECULAR PLANT 2017; 10:1026-1034. [PMID: 28698057 PMCID: PMC5673114 DOI: 10.1016/j.molp.2017.07.001] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 07/02/2017] [Accepted: 07/03/2017] [Indexed: 05/20/2023]
Abstract
Plants employ sophisticated mechanisms to interact with pathogenic as well as beneficial microbes. Of those, membrane trafficking is key in establishing a rapid and precise response. Upon interaction with pathogenic microbes, surface-localized immune receptors undergo endocytosis for signal transduction and activity regulation while cell wall components, antimicrobial compounds, and defense proteins are delivered to pathogen invasion sites through polarized secretion. To sustain mutualistic associations, host cells also reprogram the membrane trafficking system to accommodate invasive structures of symbiotic microbes. Here, we provide an analysis of recent advances in understanding the roles of secretory and endocytic membrane trafficking pathways in plant immune activation. We also discuss strategies deployed by adapted microbes to manipulate these pathways to subvert or inhibit plant defense.
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Affiliation(s)
- Yangnan Gu
- Tsinghua University-Peking University Joint Center for Life Sciences, Beijing 100084, China; Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA.
| | - Raul Zavaliev
- Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA
| | - Xinnian Dong
- Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA
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65
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Withers J, Dong X. Post-translational regulation of plant immunity. CURRENT OPINION IN PLANT BIOLOGY 2017; 38:124-132. [PMID: 28538164 PMCID: PMC5644497 DOI: 10.1016/j.pbi.2017.05.004] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 05/03/2017] [Accepted: 05/09/2017] [Indexed: 05/20/2023]
Abstract
Plants have evolved multi-layered molecular defense strategies to protect against pathogens. Plant immune signaling largely relies on post-translational modifications (PTMs) to induce rapid alterations of signaling pathways to achieve a response that is appropriate to the type of pathogen and infection pressure. In host cells, dynamic PTMs have emerged as powerful regulatory mechanisms that cells use to adjust their immune response. PTM is also a virulence strategy used by pathogens to subvert host immunity through the activities of effector proteins secreted into the host cell. Recent studies focusing on deciphering post-translational mechanisms underlying plant immunity have offered an in-depth view of how PTMs facilitate efficient immune responses and have provided a more dynamic and holistic view of plant immunity.
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Affiliation(s)
- John Withers
- Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA.
| | - Xinnian Dong
- Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA
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66
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Sabol P, Kulich I, Žárský V. RIN4 recruits the exocyst subunit EXO70B1 to the plasma membrane. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3253-3265. [PMID: 28338727 PMCID: PMC5853926 DOI: 10.1093/jxb/erx007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 01/09/2017] [Indexed: 05/22/2023]
Abstract
The exocyst is a conserved vesicle-tethering complex with principal roles in cell polarity and morphogenesis. Several studies point to its involvement in polarized secretion during microbial pathogen defense. In this context, we have found an interaction between the Arabidopsis EXO70B1 exocyst subunit, a protein which was previously associated with both the defense response and autophagy, and RPM1 INTERACTING PROTEIN 4 (RIN4), the best studied member of the NOI protein family and a known regulator of plant defense pathways. Interestingly, fragments of RIN4 mimicking the cleavage caused by the Pseudomonas syringae effector protease, AvrRpt2, fail to interact strongly with EXO70B1. We observed that transiently expressed RIN4, but not the plasma membrane (PM) protein aquaporin PIP2, recruits EXO70B1 to the PM. Unlike EXO70B1, RIN4 does not recruit the core exocyst subunit SEC6 to the PM under these conditions. Furthermore, the AvrRpt2 effector protease delivered by P. syringae is able to release both RIN4 and EXO70B1 to the cytoplasm. We present a model for how RIN4 might regulate the localization and putative function of EXO70B1 and speculate on the role the AvrRpt2 protease might have in the regulation of this defense response.
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Affiliation(s)
- Peter Sabol
- Charles University in Prague, Viničná, Prague, Czech Republic
| | - Ivan Kulich
- Charles University in Prague, Viničná, Prague, Czech Republic
- Correspondence:
| | - Viktor Žárský
- Charles University in Prague, Viničná, Prague, Czech Republic
- Institute of Experimental Botany, Rozvojová, Prague, Czech Republic
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67
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Synek L, Vukašinović N, Kulich I, Hála M, Aldorfová K, Fendrych M, Žárský V. EXO70C2 Is a Key Regulatory Factor for Optimal Tip Growth of Pollen. PLANT PHYSIOLOGY 2017; 174:223-240. [PMID: 28356503 PMCID: PMC5411130 DOI: 10.1104/pp.16.01282] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 03/25/2017] [Indexed: 05/21/2023]
Abstract
The exocyst, a eukaryotic tethering complex, coregulates targeted exocytosis as an effector of small GTPases in polarized cell growth. In land plants, several exocyst subunits are encoded by double or triple paralogs, culminating in tens of EXO70 paralogs. Out of 23 Arabidopsis thaliana EXO70 isoforms, we analyzed seven isoforms expressed in pollen. Genetic and microscopic analyses of single mutants in EXO70A2, EXO70C1, EXO70C2, EXO70F1, EXO70H3, EXO70H5, and EXO70H6 genes revealed that only a loss-of-function EXO70C2 allele resulted in a significant male-specific transmission defect (segregation 40%:51%:9%) due to aberrant pollen tube growth. Mutant pollen tubes grown in vitro exhibited an enhanced growth rate and a decreased thickness of the tip cell wall, causing tip bursts. However, exo70C2 pollen tubes could frequently recover and restart their speedy elongation, resulting in a repetitive stop-and-go growth dynamics. A pollen-specific depletion of the closest paralog, EXO70C1, using artificial microRNA in the exo70C2 mutant background, resulted in a complete pollen-specific transmission defect, suggesting redundant functions of EXO70C1 and EXO70C2. Both EXO70C1 and EXO70C2, GFP tagged and expressed under the control of their native promoters, localized in the cytoplasm of pollen grains, pollen tubes, and also root trichoblast cells. The expression of EXO70C2-GFP complemented the aberrant growth of exo70C2 pollen tubes. The absent EXO70C2 interactions with core exocyst subunits in the yeast two-hybrid assay, cytoplasmic localization, and genetic effect suggest an unconventional EXO70 function possibly as a regulator of exocytosis outside the exocyst complex. In conclusion, EXO70C2 is a novel factor contributing to the regulation of optimal tip growth of Arabidopsis pollen tubes.
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Affiliation(s)
- Lukáš Synek
- Institute of Experimental Botany, Czech Academy of Sciences, 16502 Prague 6, Czech Republic (L.S., N.V., M.H., K.A., M.F., V.Ž.); and
- Department of Experimental Botany, Faculty of Science, Charles University, 12844 Prague 2, Czech Republic (I.K., M.H., K.A., V.Ž.)
| | - Nemanja Vukašinović
- Institute of Experimental Botany, Czech Academy of Sciences, 16502 Prague 6, Czech Republic (L.S., N.V., M.H., K.A., M.F., V.Ž.); and
- Department of Experimental Botany, Faculty of Science, Charles University, 12844 Prague 2, Czech Republic (I.K., M.H., K.A., V.Ž.)
| | - Ivan Kulich
- Institute of Experimental Botany, Czech Academy of Sciences, 16502 Prague 6, Czech Republic (L.S., N.V., M.H., K.A., M.F., V.Ž.); and
- Department of Experimental Botany, Faculty of Science, Charles University, 12844 Prague 2, Czech Republic (I.K., M.H., K.A., V.Ž.)
| | - Michal Hála
- Institute of Experimental Botany, Czech Academy of Sciences, 16502 Prague 6, Czech Republic (L.S., N.V., M.H., K.A., M.F., V.Ž.); and
- Department of Experimental Botany, Faculty of Science, Charles University, 12844 Prague 2, Czech Republic (I.K., M.H., K.A., V.Ž.)
| | - Klára Aldorfová
- Institute of Experimental Botany, Czech Academy of Sciences, 16502 Prague 6, Czech Republic (L.S., N.V., M.H., K.A., M.F., V.Ž.); and
- Department of Experimental Botany, Faculty of Science, Charles University, 12844 Prague 2, Czech Republic (I.K., M.H., K.A., V.Ž.)
| | - Matyáš Fendrych
- Institute of Experimental Botany, Czech Academy of Sciences, 16502 Prague 6, Czech Republic (L.S., N.V., M.H., K.A., M.F., V.Ž.); and
- Department of Experimental Botany, Faculty of Science, Charles University, 12844 Prague 2, Czech Republic (I.K., M.H., K.A., V.Ž.)
| | - Viktor Žárský
- Institute of Experimental Botany, Czech Academy of Sciences, 16502 Prague 6, Czech Republic (L.S., N.V., M.H., K.A., M.F., V.Ž.); and
- Department of Experimental Botany, Faculty of Science, Charles University, 12844 Prague 2, Czech Republic (I.K., M.H., K.A., V.Ž.)
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Liu N, Hake K, Wang W, Zhao T, Romeis T, Tang D. CALCIUM-DEPENDENT PROTEIN KINASE5 Associates with the Truncated NLR Protein TIR-NBS2 to Contribute to exo70B1-Mediated Immunity. THE PLANT CELL 2017; 29:746-759. [PMID: 28351987 PMCID: PMC5435426 DOI: 10.1105/tpc.16.00822] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/03/2017] [Accepted: 03/24/2017] [Indexed: 05/19/2023]
Abstract
Calcium-dependent protein kinases (CPKs) function as calcium sensors and play important roles in plant immunity. Loss of function of the exocyst complex subunit EXO70B1 leads to autoimmunity caused by activation of TN2, a truncated Toll/interleukin-1 receptor-nucleotide binding sequence protein. Here we show, based on a screen for suppressors of exo70B1, that exo70B1-activated autoimmune responses require CPK5 However, the CPK5 homologs CPK4, CPK6, and CPK11, which were previously reported to function redundantly with CPK5 in effector-triggered immunity, did not contribute to exo70B1-associated phenotypes, indicating that CPK5 plays a unique role in plant immunity. Overexpressing CPK5 results in TN2-dependent autoimmunity and enhanced disease resistance, reminiscent of the exo70B1 phenotypes. Ectopic expression of CPK5 in the exo70B1 mutant led to constitutive CPK5 protein kinase activity, which was not detectable in tn2 mutants. Furthermore, TN2 interacts with the CPK5 N-terminal variable and kinase domains, stabilizing CPK5 kinase activity in vitro. This work uncovers a direct functional link between an atypical immune receptor and a crucial component of early immune signaling: increased immunity in exo70B1 depends on TN2 and CPK5 and, in a positive feedback loop, TN2 keeps CPK5 enzymatically active beyond the initiating stimulus.
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Affiliation(s)
- Na Liu
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Katharina Hake
- Department of Plant Biochemistry, Dahlem Centre of Plant Sciences, Freie Universität Berlin, 14195 Berlin, Germany
| | - Wei Wang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ting Zhao
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Tina Romeis
- Department of Plant Biochemistry, Dahlem Centre of Plant Sciences, Freie Universität Berlin, 14195 Berlin, Germany
| | - Dingzhong Tang
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
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69
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Pompa A, De Marchis F, Pallotta MT, Benitez-Alfonso Y, Jones A, Schipper K, Moreau K, Žárský V, Di Sansebastiano GP, Bellucci M. Unconventional Transport Routes of Soluble and Membrane Proteins and Their Role in Developmental Biology. Int J Mol Sci 2017; 18:ijms18040703. [PMID: 28346345 PMCID: PMC5412289 DOI: 10.3390/ijms18040703] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/22/2017] [Accepted: 03/23/2017] [Indexed: 12/30/2022] Open
Abstract
Many proteins and cargoes in eukaryotic cells are secreted through the conventional secretory pathway that brings proteins and membranes from the endoplasmic reticulum to the plasma membrane, passing through various cell compartments, and then the extracellular space. The recent identification of an increasing number of leaderless secreted proteins bypassing the Golgi apparatus unveiled the existence of alternative protein secretion pathways. Moreover, other unconventional routes for secretion of soluble or transmembrane proteins with initial endoplasmic reticulum localization were identified. Furthermore, other proteins normally functioning in conventional membrane traffic or in the biogenesis of unique plant/fungi organelles or in plasmodesmata transport seem to be involved in unconventional secretory pathways. These alternative pathways are functionally related to biotic stress and development, and are becoming more and more important in cell biology studies in yeast, mammalian cells and in plants. The city of Lecce hosted specialists working on mammals, plants and microorganisms for the inaugural meeting on “Unconventional Protein and Membrane Traffic” (UPMT) during 4–7 October 2016. The main aim of the meeting was to include the highest number of topics, summarized in this report, related to the unconventional transport routes of protein and membranes.
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Affiliation(s)
- Andrea Pompa
- Institute of Biosciences and Bioresources-Research Division of Perugia, National Research Council (CNR), via della Madonna Alta 130, 06128 Perugia, Italy.
| | - Francesca De Marchis
- Institute of Biosciences and Bioresources-Research Division of Perugia, National Research Council (CNR), via della Madonna Alta 130, 06128 Perugia, Italy.
| | | | | | - Alexandra Jones
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK.
| | - Kerstin Schipper
- Institute for Microbiology, Heinrich Heine University Düsseldorf, Düsseldorf 40225, Germany.
| | - Kevin Moreau
- Clinical Biochemistry, Institute of Metabolic Science, University of Cambridge, Cambridge CB2 1TN, UK.
| | - Viktor Žárský
- Department of Experimental Plant Biology, Faculty of Science, Charles University, 12844, Prague 2, Czech Republic.
- Institute of Experimental Botany, v.v.i., the Czech Academy of Sciences, 16502, Prague 6, Czech Republic.
| | - Gian Pietro Di Sansebastiano
- Department of Biological and Environmental Sciences and Technologies (DISTEBA), University of Salento, S.P. 6, 73100 Lecce, Italy.
| | - Michele Bellucci
- Institute of Biosciences and Bioresources-Research Division of Perugia, National Research Council (CNR), via della Madonna Alta 130, 06128 Perugia, Italy.
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Sekereš J, Pejchar P, Šantrůček J, Vukašinović N, Žárský V, Potocký M. Analysis of Exocyst Subunit EXO70 Family Reveals Distinct Membrane Polar Domains in Tobacco Pollen Tubes. PLANT PHYSIOLOGY 2017; 173:1659-1675. [PMID: 28082718 PMCID: PMC5338673 DOI: 10.1104/pp.16.01709] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 01/10/2017] [Indexed: 05/05/2023]
Abstract
The vesicle-tethering complex exocyst is one of the crucial cell polarity regulators. The EXO70 subunit is required for the targeting of the complex and is represented by many isoforms in angiosperm plant cells. This diversity could be partly responsible for the establishment and maintenance of membrane domains with different composition. To address this hypothesis, we employed the growing pollen tube, a well-established cell polarity model system, and performed large-scale expression, localization, and functional analysis of tobacco (Nicotiana tabacum) EXO70 isoforms. Various isoforms localized to different regions of the pollen tube plasma membrane, apical vesicle-rich inverted cone region, nucleus, and cytoplasm. The overexpression of major pollen-expressed EXO70 isoforms resulted in growth arrest and characteristic phenotypic deviations of tip swelling and apical invaginations. NtEXO70A1a and NtEXO70B1 occupied two distinct and mutually exclusive plasma membrane domains. Both isoforms partly colocalized with the exocyst subunit NtSEC3a at the plasma membrane, possibly forming different exocyst complex subpopulations. NtEXO70A1a localized to the small area previously characterized as the site of exocytosis in the tobacco pollen tube, while NtEXO70B1 surprisingly colocalized with the zone of clathrin-mediated endocytosis. Both NtEXO70A1a and NtEXO70B1 colocalized to different degrees with markers for the anionic signaling phospholipids phosphatidylinositol 4,5-bisphosphate and phosphatidic acid. In contrast, members of the EXO70 C class, which are specifically expressed in tip-growing cells, exhibited exocytosis-related functional effects in pollen tubes despite the absence of apparent plasma membrane localization. Taken together, our data support the existence of multiple membrane-trafficking domains regulated by different EXO70-containing exocyst complexes within a single cell.
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Affiliation(s)
- Juraj Sekereš
- Institute of Experimental Botany, Czech Academy of Sciences, Prague 6, Czech Republic (J.S., P.P., N.V., V.Ž., M.P.)
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, Czech Republic (J.S., V.Ž.); and
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague 6, Czech Republic (J.Š.)
| | - Přemysl Pejchar
- Institute of Experimental Botany, Czech Academy of Sciences, Prague 6, Czech Republic (J.S., P.P., N.V., V.Ž., M.P.)
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, Czech Republic (J.S., V.Ž.); and
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague 6, Czech Republic (J.Š.)
| | - Jiří Šantrůček
- Institute of Experimental Botany, Czech Academy of Sciences, Prague 6, Czech Republic (J.S., P.P., N.V., V.Ž., M.P.)
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, Czech Republic (J.S., V.Ž.); and
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague 6, Czech Republic (J.Š.)
| | - Nemanja Vukašinović
- Institute of Experimental Botany, Czech Academy of Sciences, Prague 6, Czech Republic (J.S., P.P., N.V., V.Ž., M.P.)
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, Czech Republic (J.S., V.Ž.); and
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague 6, Czech Republic (J.Š.)
| | - Viktor Žárský
- Institute of Experimental Botany, Czech Academy of Sciences, Prague 6, Czech Republic (J.S., P.P., N.V., V.Ž., M.P.)
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, Czech Republic (J.S., V.Ž.); and
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague 6, Czech Republic (J.Š.)
| | - Martin Potocký
- Institute of Experimental Botany, Czech Academy of Sciences, Prague 6, Czech Republic (J.S., P.P., N.V., V.Ž., M.P.);
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, Czech Republic (J.S., V.Ž.); and
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague 6, Czech Republic (J.Š.)
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Seo DH, Ahn MY, Park KY, Kim EY, Kim WT. The N-Terminal UND Motif of the Arabidopsis U-Box E3 Ligase PUB18 Is Critical for the Negative Regulation of ABA-Mediated Stomatal Movement and Determines Its Ubiquitination Specificity for Exocyst Subunit Exo70B1. THE PLANT CELL 2016; 28:2952-2973. [PMID: 27956469 PMCID: PMC5240735 DOI: 10.1105/tpc.16.00347] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 11/18/2016] [Accepted: 12/09/2016] [Indexed: 05/20/2023]
Abstract
The Arabidopsis thaliana U-box E3 ligases PUB18/PUB19 and PUB22/PUB23 are negative regulators of drought stress responses. PUB18/PUB19 regulate the drought stress response in an abscisic acid (ABA)-dependent manner, whereas PUB22/PUB23 regulate this response in an ABA-independent manner. A major structural difference between PUB18/PUB19 and PUB22/PUB23 is the presence of the UND (U-box N-terminal domain). Here, we focused on elucidating the molecular mechanism that mediates the functional difference between PUB18 and PUB22 and found that the UNDPUB18 was critically involved in the negative regulation of ABA-mediated stomatal movements. Exo70B1, a subunit of the exocyst complex, was identified as a target of PUB18, whereas Exo70B2 was a substrate of PUB22. However, the ∆UND-PUB18 derivative failed to ubiquitinate Exo70B1, but ubiquitinated Exo70B2. By contrast, the UNDPUB18-PUB22 chimeric protein ubiquitinated Exo70B1 instead of Exo70B2, suggesting that the ubiquitination specificities of PUB18 and PUB22 to Exo70B1 and Exo70B2, respectively, are dependent on the presence or absence of the UNDPUB18 motif. The ABA-insensitive phenotypes of the pub18 pub19 exo70b1 triple mutant were reminiscent of those of exo70b1 rather than pub18 pub19, indicating that Exo70B1 functions downstream of PUB18. Overall, our results suggest that the UNDPUB18 motif is crucial for the negative regulation of ABA-dependent stomatal movement and for determination of its ubiquitination specificity to Exo70B1.
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Affiliation(s)
- Dong Hye Seo
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Min Yong Ahn
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Ki Youl Park
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Eun Yu Kim
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Woo Taek Kim
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
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Bloch D, Pleskot R, Pejchar P, Potocký M, Trpkošová P, Cwiklik L, Vukašinović N, Sternberg H, Yalovsky S, Žárský V. Exocyst SEC3 and Phosphoinositides Define Sites of Exocytosis in Pollen Tube Initiation and Growth. PLANT PHYSIOLOGY 2016; 172:980-1002. [PMID: 27516531 PMCID: PMC5047084 DOI: 10.1104/pp.16.00690] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 08/08/2016] [Indexed: 05/16/2023]
Abstract
Polarized exocytosis is critical for pollen tube growth, but its localization and function are still under debate. The exocyst vesicle-tethering complex functions in polarized exocytosis. Here, we show that a sec3a exocyst subunit null mutant cannot be transmitted through the male gametophyte due to a defect in pollen tube growth. The green fluorescent protein (GFP)-SEC3a fusion protein is functional and accumulates at or proximal to the pollen tube tip plasma membrane. Partial complementation of sec3a resulted in the development of pollen with multiple tips, indicating that SEC3 is required to determine the site of pollen germination pore formation. Time-lapse imaging demonstrated that SEC3a and SEC8 were highly dynamic and that SEC3a localization on the apical plasma membrane predicts the direction of growth. At the tip, polar SEC3a domains coincided with cell wall deposition. Labeling of GFP-SEC3a-expressing pollen with the endocytic marker FM4-64 revealed the presence of subdomains on the apical membrane characterized by extensive exocytosis. In steady-state growing tobacco (Nicotiana tabacum) pollen tubes, SEC3a displayed amino-terminal Pleckstrin homology-like domain (SEC3a-N)-dependent subapical membrane localization. In agreement, SEC3a-N interacted with phosphoinositides in vitro and colocalized with a phosphatidylinositol 4,5-bisphosphate (PIP2) marker in pollen tubes. Correspondingly, molecular dynamics simulations indicated that SEC3a-N associates with the membrane by interacting with PIP2 However, the interaction with PIP2 is not required for polar localization and the function of SEC3a in Arabidopsis (Arabidopsis thaliana). Taken together, our findings indicate that SEC3a is a critical determinant of polar exocytosis during tip growth and suggest differential regulation of the exocytotic machinery depending on pollen tube growth modes.
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Affiliation(s)
- Daria Bloch
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Roman Pleskot
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Přemysl Pejchar
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Martin Potocký
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Pavlína Trpkošová
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Lukasz Cwiklik
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Nemanja Vukašinović
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Hasana Sternberg
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Shaul Yalovsky
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Viktor Žárský
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
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73
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Golubov A, Byeon B, Woycicki R, Laing C, Gannon V, Kovalchuk I. Transcriptomic profiling of Arabidopsis thaliana plants exposed to the human pathogen Escherichia coli O157-H7. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2016. [DOI: 10.1016/j.bcab.2016.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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74
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Tan X, Feng Y, Liu Y, Bao Y. Mutations in exocyst complex subunit SEC6 gene impaired polar auxin transport and PIN protein recycling in Arabidopsis primary root. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 250:97-104. [PMID: 27457987 DOI: 10.1016/j.plantsci.2016.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/04/2016] [Accepted: 06/01/2016] [Indexed: 06/06/2023]
Abstract
Polar auxin transport, which is critical for land plant pattern formation and directional growth, is largely depended on asymmetric distribution of PIN proteins at the plasma membrane (PM). Endocytosis and recycling processes play important roles in regulating PIN protein distribution and abundance at the PM. Two subunits (SEC8, EXO70A1) of exocyst, an octameric vesicle-tethering complex, have been reported to be involved in PIN protein recycling in Arabidopsis. However, the function of exocyst complex in PIN protein recycling and polar auxin transport remains incompletely understood. In this study, we utilized two SEC6 down-regulation mutants (PRsec6-1 and PRsec6-2) to investigate the role of exocyst subunit SEC6 in the primary root development, polar auxin transport and PIN proteins recycling. We found that in PRsec6 mutants: 1. Primary root growth was retarded, and lateral root initiation were compromised. 2. Primary roots were sensitive to exogenous auxin 1-napthalene acetic acid (NAA) but not 2,4-dichlorophenoxy (2.4-D). 3. Recycling of PIN1 and PIN2 proteins from the Brefeldin A (BFA) compartment to the PM was delayed. 4. Vesicles accumulated in the primary root tip cells, especially accumulated in the cytosol closed to the PM. These results further demonstrated that the exocyst complex plays an important role in PIN protein recycling and polar auxin transport in Arabidopsis primary root.
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Affiliation(s)
- Xiaoyun Tan
- College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Yihong Feng
- College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Yulong Liu
- College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Yiqun Bao
- College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, PR China.
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75
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Wang Z, Li P, Yang Y, Chi Y, Fan B, Chen Z. Expression and Functional Analysis of a Novel Group of Legume-specific WRKY and Exo70 Protein Variants from Soybean. Sci Rep 2016; 6:32090. [PMID: 27572297 PMCID: PMC5004194 DOI: 10.1038/srep32090] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 08/02/2016] [Indexed: 12/22/2022] Open
Abstract
Legumes fix atmospheric nitrogen through symbiosis with microorganisms and contain special traits in nitrogen assimilation and associated processes. Recently, we have reported a novel WRKY-related protein (GmWRP1) and a new clade of Exo70 proteins (GmExo70J) from soybean with homologs found only in legumes. GmWRP1 and some of the GmExo70J proteins are localized to Golgi apparatus through a novel N-terminal transmembrane domain. Here, we report further analysis of expression and functions of the novel GmWRP1 and GmExo70J genes. Promoter-GUS analysis in Arabidopsis revealed distinct tissue-specific expression patterns of the GmExo70J genes not only in vegetative but also in reproductive organs including mature tissues, where expression of previously characterized Exo70 genes is usually absent. Furthermore, expression of some GmExo70J genes including GmExo70J1, GmExo70J6 and GmExo70J7 increases greatly in floral organ-supporting receptacles during the development and maturation of siliques, indicating a possible role in seed development. More importantly, suppression of GmWRP1, GmExo70J7, GmExo70J8 and GmExo70J9 expression in soybean using virus- or artificial microRNA-mediated gene silencing resulted in accelerated leaf senescence and reduced nodule formation. These results strongly suggest that legume-specific GmWRP1 and GmExo70J proteins play important roles not only in legume symbiosis but also in other processes critical for legume growth and development.
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Affiliation(s)
- Ze Wang
- Department of Horticulture, Zijingang Campus, 866 Yuhangtang Road, Zhejiang University, Hangzhou, 310058, China
| | - Panfeng Li
- Department of Horticulture, Zijingang Campus, 866 Yuhangtang Road, Zhejiang University, Hangzhou, 310058, China
| | - Yan Yang
- Department of Horticulture, Zijingang Campus, 866 Yuhangtang Road, Zhejiang University, Hangzhou, 310058, China
| | - Yingjun Chi
- Department of Horticulture, Zijingang Campus, 866 Yuhangtang Road, Zhejiang University, Hangzhou, 310058, China
| | - Baofang Fan
- Department of Botany and Plant Pathology, 915 W. State Street, Purdue University, West Lafayette, IN 47907, USA
| | - Zhixiang Chen
- Department of Horticulture, Zijingang Campus, 866 Yuhangtang Road, Zhejiang University, Hangzhou, 310058, China
- Department of Botany and Plant Pathology, 915 W. State Street, Purdue University, West Lafayette, IN 47907, USA
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76
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Toruño TY, Stergiopoulos I, Coaker G. Plant-Pathogen Effectors: Cellular Probes Interfering with Plant Defenses in Spatial and Temporal Manners. ANNUAL REVIEW OF PHYTOPATHOLOGY 2016; 54:419-41. [PMID: 27359369 PMCID: PMC5283857 DOI: 10.1146/annurev-phyto-080615-100204] [Citation(s) in RCA: 385] [Impact Index Per Article: 48.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Plants possess large arsenals of immune receptors capable of recognizing all pathogen classes. To cause disease, pathogenic organisms must be able to overcome physical barriers, suppress or evade immune perception, and derive nutrients from host tissues. Consequently, to facilitate some of these processes, pathogens secrete effector proteins that promote colonization. This review covers recent advances in the field of effector biology, focusing on conserved cellular processes targeted by effectors from diverse pathogens. The ability of effectors to facilitate pathogen entry into the host interior, suppress plant immune perception, and alter host physiology for pathogen benefit is discussed. Pathogens also deploy effectors in a spatial and temporal manner, depending on infection stage. Recent advances have also enhanced our understanding of effectors acting in specific plant organs and tissues. Effectors are excellent cellular probes that facilitate insight into biological processes as well as key points of vulnerability in plant immune signaling networks.
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Affiliation(s)
- Tania Y Toruño
- Department of Plant Pathology, University of California, Davis, California; , ,
| | | | - Gitta Coaker
- Department of Plant Pathology, University of California, Davis, California; , ,
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77
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Contributions of host cellular trafficking and organization to the outcomes of plant-pathogen interactions. Semin Cell Dev Biol 2016; 56:163-173. [DOI: 10.1016/j.semcdb.2016.05.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 05/16/2016] [Accepted: 05/20/2016] [Indexed: 11/23/2022]
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78
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Vukašinović N, Žárský V. Tethering Complexes in the Arabidopsis Endomembrane System. Front Cell Dev Biol 2016; 4:46. [PMID: 27243010 PMCID: PMC4871884 DOI: 10.3389/fcell.2016.00046] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/02/2016] [Indexed: 12/30/2022] Open
Abstract
Targeting of endomembrane transport containers is of the utmost importance for proper land plant growth and development. Given the immobility of plant cells, localized membrane vesicle secretion and recycling are amongst the main processes guiding proper cell, tissue and whole plant morphogenesis. Cell wall biogenesis and modification are dependent on vectorial membrane traffic, not only during normal development, but also in stress responses and in plant defense against pathogens and/or symbiosis. It is surprising how little we know about these processes in plants, from small GTPase regulation to the tethering complexes that act as their effectors. Tethering factors are single proteins or protein complexes mediating first contact between the target membrane and arriving membrane vesicles. In this review we focus on the tethering complexes of the best-studied plant model—Arabidopsis thaliana. Genome-based predictions indicate the presence of all major tethering complexes in plants that are known from a hypothetical last eukaryotic common ancestor (LECA). The evolutionary multiplication of paralogs of plant tethering complex subunits has produced the massively expanded EXO70 family, indicating a subfunctionalization of the terminal exocytosis machinery in land plants. Interpretation of loss of function (LOF) mutant phenotypes has to consider that related, yet clearly functionally-specific complexes often share some common core subunits. It is therefore impossible to conclude with clarity which version of the complex is responsible for the phenotypic deviations observed. Experimental interest in the analysis of plant tethering complexes is growing and we hope to contribute with this review by attracting even more attention to this fascinating field of plant cell biology.
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Affiliation(s)
- Nemanja Vukašinović
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University Prague, Czech Republic
| | - Viktor Žárský
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University Prague, Czech Republic
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79
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Abstract
Abstract
A large number of pathogenic microorganisms cause rice diseases that lead to enormous yield losses worldwide. Such losses are important because rice is a staple food for more than half of the world's population. Over the past two decades, the extensive study of the molecular interactions between rice and the fungal pathogen Magnaporthe oryzae and between rice and the bacterial pathogen Xanthomonas oryzae pv. oryzae has made rice a model for investigating plant–microbe interactions of monocotyledons. Impressive progress has been recently achieved in understanding the molecular basis of rice pathogen-associated molecular pattern-immunity and effector-triggered immunity. Here, we briefly summarize these recent advances, emphasizing the diverse functions of the structurally conserved fungal effectors, the regulatory mechanisms of the immune receptor complexes, and the novel strategies for breeding disease resistance. We also discuss future research challenges.
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Affiliation(s)
- Wende Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Guo-Liang Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Department of Plant Pathology, Ohio State University, Columbus, OH 43210, USA
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80
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Martin-Urdiroz M, Deeks MJ, Horton CG, Dawe HR, Jourdain I. The Exocyst Complex in Health and Disease. Front Cell Dev Biol 2016; 4:24. [PMID: 27148529 PMCID: PMC4828438 DOI: 10.3389/fcell.2016.00024] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 03/11/2016] [Indexed: 01/23/2023] Open
Abstract
Exocytosis involves the fusion of intracellular secretory vesicles with the plasma membrane, thereby delivering integral membrane proteins to the cell surface and releasing material into the extracellular space. Importantly, exocytosis also provides a source of lipid moieties for membrane extension. The tethering of the secretory vesicle before docking and fusion with the plasma membrane is mediated by the exocyst complex, an evolutionary conserved octameric complex of proteins. Recent findings indicate that the exocyst complex also takes part in other intra-cellular processes besides secretion. These various functions seem to converge toward defining a direction of membrane growth in a range of systems from fungi to plants and from neurons to cilia. In this review we summarize the current knowledge of exocyst function in cell polarity, signaling and cell-cell communication and discuss implications for plant and animal health and disease.
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Affiliation(s)
| | - Michael J Deeks
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Connor G Horton
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Helen R Dawe
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Isabelle Jourdain
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
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81
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Kim SJ, Brandizzi F. The plant secretory pathway for the trafficking of cell wall polysaccharides and glycoproteins. Glycobiology 2016; 26:940-949. [PMID: 27072815 DOI: 10.1093/glycob/cww044] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 04/03/2016] [Indexed: 01/22/2023] Open
Abstract
Plant endomembranes are required for the biosynthesis and secretion of complex cell wall matrix polysaccharides, glycoproteins and proteoglycans. To define the biochemical roadmap that guides the synthesis and deposition of these cell wall components it is first necessary to outline the localization of the biosynthetic and modifying enzymes involved, as well as the distribution of the intermediate and final constituents of the cell wall. Thus far, a comprehensive understanding of cell wall matrix components has been hampered by the multiplicity of trafficking routes in the secretory pathway, and the diverse biosynthetic roles of the endomembrane organelles, which may exhibit tissue and development specific features. However, the recent identification of protein complexes producing matrix polysaccharides, and those supporting the synthesis and distribution of a grass-specific hemicellulose are advancing our understanding of the functional contribution of the plant secretory pathway in cell wall biosynthesis. In this review, we provide an overview of the plant membrane trafficking routes and report on recent exciting accomplishments in the understanding of the mechanisms underlying secretion with focus on cell wall synthesis in plants.
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Affiliation(s)
- Sang-Jin Kim
- Great Lakes Bioenergy Research Center Michigan State University-DOE Plant Research Laboratory
| | - Federica Brandizzi
- Great Lakes Bioenergy Research Center Michigan State University-DOE Plant Research Laboratory Department of Plant Biology, Michigan State University, East Lansing, MI, USA
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82
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Kumar K, Srivastava V, Purayannur S, Kaladhar VC, Cheruvu PJ, Verma PK. WRKY domain-encoding genes of a crop legume chickpea (Cicer arietinum): comparative analysis with Medicago truncatula WRKY family and characterization of group-III gene(s). DNA Res 2016; 23:225-39. [PMID: 27060167 PMCID: PMC4909309 DOI: 10.1093/dnares/dsw010] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 02/20/2016] [Indexed: 11/16/2022] Open
Abstract
The WRKY genes have been identified as important transcriptional modulators predominantly during the environmental stresses, but they also play critical role at various stages of plant life cycle. We report the identification of WRKY domain (WD)-encoding genes from galegoid clade legumes chickpea (Cicer arietinum L.) and barrel medic (Medicago truncatula). In total, 78 and 98 WD-encoding genes were found in chickpea and barrel medic, respectively. Comparative analysis suggests the presence of both conserved and unique WRKYs, and expansion of WRKY family in M. truncatula primarily by tandem duplication. Exclusively found in galegoid legumes, CaWRKY16 and its orthologues encode for a novel protein having a transmembrane and partial Exo70 domains flanking a group-III WD. Genomic region of galegoids, having CaWRKY16, is more dynamic when compared with millettioids. In onion cells, fused CaWRKY16-EYFP showed punctate fluorescent signals in cytoplasm. The chickpea WRKY group-III genes were further characterized for their transcript level modulation during pathogenic stress and treatments of abscisic acid, jasmonic acid, and salicylic acid (SA) by real-time PCR. Differential regulation of genes was observed during Ascochyta rabiei infection and SA treatment. Characterization of A. rabiei and SA inducible gene CaWRKY50 showed that it localizes to plant nucleus, binds to W-box, and have a C-terminal transactivation domain. Overexpression of CaWRKY50 in tobacco plants resulted in early flowering and senescence. The in-depth comparative account presented here for two legume WRKY genes will be of great utility in hastening functional characterization of crop legume WRKYs and will also help in characterization of Exo70Js.
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Affiliation(s)
- Kamal Kumar
- Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Vikas Srivastava
- Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Savithri Purayannur
- Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - V Chandra Kaladhar
- School of Life Sciences, Central University of Gujarat, Gandhinagar 382030, Gujarat, India
| | - Purnima Jaiswal Cheruvu
- Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Praveen Kumar Verma
- Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
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83
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Robinson DG, Ding Y, Jiang L. Unconventional protein secretion in plants: a critical assessment. PROTOPLASMA 2016; 253:31-43. [PMID: 26410830 DOI: 10.1007/s00709-015-0887-1] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 09/18/2015] [Indexed: 05/27/2023]
Abstract
Unconventional protein secretion (UPS) is a collective term for mechanisms by which cytosolic proteins that lack a signal peptide ("leaderless secretory proteins" (LSPs)) can gain access to the cell exterior. Numerous examples of UPS have been well documented in animal and yeast cells. In contrast, our understanding of the mechanism(s) and function of UPS in plants is very limited. This review evaluates the available literature on this subject. The apparent large numbers of LSPs in the plant secretome suggest that UPS also occurs in plants but is not a proof. Although the direct transport of LSPs across the plant plasma membrane (PM) has not yet been described, it is possible that as in other eukaryotes, exosomes may be released from plant cells through fusion of multivesicular bodies (MVBs) with the PM. In this way, LSPs, but also small RNAs (sRNAs), that are passively taken up from the cytosol into the intraluminal vesicles of MVBs, could reach the apoplast. Another possible mechanism is the recently discovered exocyst-positive organelle (EXPO), a double-membrane-bound compartment, distinct from autophagosomes, which appears to sequester LSPs.
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Affiliation(s)
- David G Robinson
- Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, D-69120, Heidelberg, Germany.
| | - Yu Ding
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Liwen Jiang
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
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84
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Disruption of OsEXO70A1 Causes Irregular Vascular Bundles and Perturbs Mineral Nutrient Assimilation in Rice. Sci Rep 2015; 5:18609. [PMID: 26691393 PMCID: PMC4686888 DOI: 10.1038/srep18609] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/23/2015] [Indexed: 11/08/2022] Open
Abstract
Normal uptake, transportation, and assimilation of primary nutrients are essential to plant growth. Tracheary elements (TEs) are tissues responsible for the transport of water and minerals and characterized by patterned secondary cell wall (SCW) thickening. Exocysts are involved in the regulation of SCW deposition by mediating the targeted transport of materials and enzymes to specific membrane areas. EXO70s are highly duplicated in plants and provide exocysts with functional specificity. In this study, we report the isolation of a rice mutant rapid leaf senescence2 (rls2) that exhibits dwarfism, ferruginous spotted necrotic leaves, decreased hydraulic transport, and disordered primary nutrient assimilation. Histological analysis of rls2-1 mutants has indicated impaired cell expansion, collapsed vascular tissues, and irregular SCW deposition. Map-based cloning has revealed that RLS2 encodes OsEXO70A1, which is one of the 47 members of EXO70s in rice. RLS2 was widely expressed and spatially restricted in vascular bundles. Subcellular localization analysis demonstrated that RLS2 was present on both membrane and nuclear regions. Expression analysis revealed that mutations in rls2 triggers transcriptional fluctuation of orthologous EXO70 genes and affects genes involved in primary nutrient absorption and transport. In brief, our study revealed that RLS2 is required for normal vascular bundle differentiation and primary nutrient assimilation.
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85
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Safavian D, Zayed Y, Indriolo E, Chapman L, Ahmed A, Goring DR. RNA Silencing of Exocyst Genes in the Stigma Impairs the Acceptance of Compatible Pollen in Arabidopsis. PLANT PHYSIOLOGY 2015; 169:2526-38. [PMID: 26443677 PMCID: PMC4677879 DOI: 10.1104/pp.15.00635] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 10/06/2015] [Indexed: 05/19/2023]
Abstract
Initial pollen-pistil interactions in the Brassicaceae are regulated by rapid communication between pollen grains and stigmatic papillae and are fundamentally important, as they are the first step toward successful fertilization. The goal of this study was to examine the requirement of exocyst subunits, which function in docking secretory vesicles to sites of polarized secretion, in the context of pollen-pistil interactions. One of the exocyst subunit genes, EXO70A1, was previously identified as an essential factor in the stigma for the acceptance of compatible pollen in Arabidopsis (Arabidopsis thaliana) and Brassica napus. We hypothesized that EXO70A1, along with other exocyst subunits, functions in the Brassicaceae dry stigma to deliver cargo-bearing secretory vesicles to the stigmatic papillar plasma membrane, under the pollen attachment site, for pollen hydration and pollen tube entry. Here, we investigated the functions of exocyst complex genes encoding the remaining seven subunits, SECRETORY3 (SEC3), SEC5, SEC6, SEC8, SEC10, SEC15, and EXO84, in Arabidopsis stigmas following compatible pollinations. Stigma-specific RNA-silencing constructs were used to suppress the expression of each exocyst subunit individually. The early postpollination stages of pollen grain adhesion, pollen hydration, pollen tube penetration, seed set, and overall fertility were analyzed in the transgenic lines to evaluate the requirement of each exocyst subunit. Our findings provide comprehensive evidence that all eight exocyst subunits are necessary in the stigma for the acceptance of compatible pollen. Thus, this work implicates a fully functional exocyst complex as a component of the compatible pollen response pathway to promote pollen acceptance.
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Affiliation(s)
- Darya Safavian
- Department of Cell and Systems Biology and Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, Canada M5S 3B2
| | - Yara Zayed
- Department of Cell and Systems Biology and Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, Canada M5S 3B2
| | - Emily Indriolo
- Department of Cell and Systems Biology and Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, Canada M5S 3B2
| | - Laura Chapman
- Department of Cell and Systems Biology and Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, Canada M5S 3B2
| | - Abdalla Ahmed
- Department of Cell and Systems Biology and Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, Canada M5S 3B2
| | - Daphne R Goring
- Department of Cell and Systems Biology and Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, Canada M5S 3B2
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86
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Endosidin2 targets conserved exocyst complex subunit EXO70 to inhibit exocytosis. Proc Natl Acad Sci U S A 2015; 113:E41-50. [PMID: 26607451 DOI: 10.1073/pnas.1521248112] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The exocyst complex regulates the last steps of exocytosis, which is essential to organisms across kingdoms. In humans, its dysfunction is correlated with several significant diseases, such as diabetes and cancer progression. Investigation of the dynamic regulation of the evolutionarily conserved exocyst-related processes using mutants in genetically tractable organisms such as Arabidopsis thaliana is limited by the lethality or the severity of phenotypes. We discovered that the small molecule Endosidin2 (ES2) binds to the EXO70 (exocyst component of 70 kDa) subunit of the exocyst complex, resulting in inhibition of exocytosis and endosomal recycling in both plant and human cells and enhancement of plant vacuolar trafficking. An EXO70 protein with a C-terminal truncation results in dominant ES2 resistance, uncovering possible distinct regulatory roles for the N terminus of the protein. This study not only provides a valuable tool in studying exocytosis regulation but also offers a potentially new target for drugs aimed at addressing human disease.
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87
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Du Y, Mpina MH, Birch PRJ, Bouwmeester K, Govers F. Phytophthora infestans RXLR Effector AVR1 Interacts with Exocyst Component Sec5 to Manipulate Plant Immunity. PLANT PHYSIOLOGY 2015; 169:1975-90. [PMID: 26336092 PMCID: PMC4634092 DOI: 10.1104/pp.15.01169] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 08/30/2015] [Indexed: 05/24/2023]
Abstract
Phytophthora infestans secretes numerous RXLR effectors that modulate host defense and thereby pave the way for successful invasion. Here, we show that the RXLR effector AVR1 is a virulence factor that promotes colonization and suppresses callose deposition, a hallmark of basal defense. To identify host targets of AVR1, we performed yeast two-hybrid screens and selected Sec5 as a candidate. Sec5 is a subunit of the exocyst, a protein complex that is involved in vesicle trafficking. AVR1-like (A-L), a close homolog of AVR1, also acts as a virulence factor, but unlike AVR1, A-L does not suppress CRINKLER2 (CRN2)-induced cell death or interact with Sec5. Compared with AVR1, A-L is shorter and lacks the carboxyl-terminal tail, the T-region that is crucial for CRN2-induced cell death suppression and Sec5 interaction. In planta analyses revealed that AVR1 and Sec5 are in close proximity, and coimmunoprecipitation confirmed the interaction. Sec5 is required for secretion of the pathogenesis-related protein PR-1 and callose deposition and also plays a role in CRN2-induced cell death. Our findings show that P. infestans manipulates an exocyst subunit and thereby potentially disturbs vesicle trafficking, a cellular process that is important for basal defense. This is a novel strategy that oomycete pathogens exploit to modulate host defense.
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Affiliation(s)
- Yu Du
- Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, The Netherlands (Y.D., M.H.M., K.B., F.G.);Division of Plant Sciences, College of Life Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, United Kingdom (P.R.J.B.); andPlant-Microbe Interactions, Department of Biology, Faculty of Science, Utrecht University, 3584 CH, Utrecht, The Netherlands (K.B.)
| | - Mohamed H Mpina
- Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, The Netherlands (Y.D., M.H.M., K.B., F.G.);Division of Plant Sciences, College of Life Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, United Kingdom (P.R.J.B.); andPlant-Microbe Interactions, Department of Biology, Faculty of Science, Utrecht University, 3584 CH, Utrecht, The Netherlands (K.B.)
| | - Paul R J Birch
- Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, The Netherlands (Y.D., M.H.M., K.B., F.G.);Division of Plant Sciences, College of Life Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, United Kingdom (P.R.J.B.); andPlant-Microbe Interactions, Department of Biology, Faculty of Science, Utrecht University, 3584 CH, Utrecht, The Netherlands (K.B.)
| | - Klaas Bouwmeester
- Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, The Netherlands (Y.D., M.H.M., K.B., F.G.);Division of Plant Sciences, College of Life Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, United Kingdom (P.R.J.B.); andPlant-Microbe Interactions, Department of Biology, Faculty of Science, Utrecht University, 3584 CH, Utrecht, The Netherlands (K.B.)
| | - Francine Govers
- Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, The Netherlands (Y.D., M.H.M., K.B., F.G.);Division of Plant Sciences, College of Life Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, United Kingdom (P.R.J.B.); andPlant-Microbe Interactions, Department of Biology, Faculty of Science, Utrecht University, 3584 CH, Utrecht, The Netherlands (K.B.)
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88
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Fujisaki K, Abe Y, Ito A, Saitoh H, Yoshida K, Kanzaki H, Kanzaki E, Utsushi H, Yamashita T, Kamoun S, Terauchi R. Rice Exo70 interacts with a fungal effector, AVR-Pii, and is required for AVR-Pii-triggered immunity. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 83:875-87. [PMID: 26186703 DOI: 10.1111/tpj.12934] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 06/26/2015] [Accepted: 06/26/2015] [Indexed: 05/03/2023]
Abstract
Vesicle trafficking including the exocytosis pathway is intimately associated with host immunity against pathogens. However, we still have insufficient knowledge about how it contributes to immunity, and how pathogen factors affect it. In this study, we explore host factors that interact with the Magnaporthe oryzae effector AVR-Pii. Gel filtration chromatography and co-immunoprecipitation assays identified a 150 kDa complex of proteins in the soluble fraction comprising AVR-Pii and OsExo70-F2 and OsExo70-F3, two rice Exo70 proteins presumably involved in exocytosis. Simultaneous knockdown of OsExo70-F2 and F3 totally abrogated Pii immune receptor-dependent resistance, but had no effect on Pia- and Pik-dependent resistance. Knockdown levels of OsExo70-F3 but not OsExo70-F2 correlated with reduction of Pii function, suggesting that OsExo70-F3 is specifically involved in Pii-dependent resistance. Under our current experimental conditions, over-expression of AVR-Pii or knockdown of OsExo70-F2 and -F3 genes in rice did not affect the virulence of compatible isolates of M. oryzae. AVR-Pii interaction with OsExo70-F3 appears to play a crucial role in immunity triggered by Pii, suggesting a role for OsExo70 as a decoy or helper in Pii/AVR-Pii interactions.
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Affiliation(s)
- Koki Fujisaki
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
| | - Yoshiko Abe
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
| | - Akiko Ito
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
| | | | - Kentaro Yoshida
- Organization of Advanced Science and Technology, Kobe University, Kobe, Hyogo, Japan
| | | | - Eiko Kanzaki
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
| | - Hiroe Utsushi
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
| | | | - Sophien Kamoun
- The Sainsbury Laboratory, Norwich Research Park, Norwich, UK
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89
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Feussner I, Polle A. What the transcriptome does not tell - proteomics and metabolomics are closer to the plants' patho-phenotype. CURRENT OPINION IN PLANT BIOLOGY 2015; 26:26-31. [PMID: 26051215 DOI: 10.1016/j.pbi.2015.05.023] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 05/18/2015] [Accepted: 05/18/2015] [Indexed: 05/18/2023]
Abstract
The proteome and metabolome of the plant provide a wealth of additional information on plant-microbe interactions since they not only represent additional levels of regulation, but often they harbor the end products of regulatory processes. Proteomics has contributed to our understanding of plant-microbe research by increasing the spatial resolution of the analysis within the infected tissue, because components of the basal immunity were uncovered in the apoplast. Metabolomics has developed into a powerful approach to discover the role of small molecules during plant-microbe interactions in non-model plants since it does not depend on the availability of genome or transcriptome data. Moreover, novel molecules involved in systemic acquired resistance and the precursors for the formation of molecules that provide physical barriers to prevent spreading of pathogens were identified.
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Affiliation(s)
- Ivo Feussner
- Georg-August-University, Albrecht-von-Haller-Institute for Plant Sciences, Department of Plant Biochemistry, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.
| | - Andrea Polle
- Georg-August University, Büsgen-Institute, Department for Forest Botany and Tree Physiology, Büsgenweg 2, 37077 Göttingen, Germany
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90
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Zhang X, Pumplin N, Ivanov S, Harrison MJ. EXO70I Is Required for Development of a Sub-domain of the Periarbuscular Membrane during Arbuscular Mycorrhizal Symbiosis. Curr Biol 2015; 25:2189-95. [PMID: 26234213 DOI: 10.1016/j.cub.2015.06.075] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 04/02/2015] [Accepted: 06/30/2015] [Indexed: 12/17/2022]
Abstract
In eukaryotic cells, polarized secretion mediated by exocytotic fusion of membrane vesicles with the plasma membrane is essential for spatially restricted expansion of the plasma membrane and for the delivery of molecules to specific locations at the membrane and/or cell surface. The EXOCYST complex is central to this process, and in yeast, regulation of the EXO70 subunit influences exocytosis and cargo specificity. In contrast to yeast and mammalian cells, plants have upwards of 23 EXO70 genes with largely unknown roles. During arbuscular mycorrhizal (AM) symbiosis, deposition of the plant periarbuscular membrane (PAM) around the fungal arbuscule creates an intracellular membrane interface between the symbionts. The PAM has two major membrane sub-domains, and symbiosis-specific transporter proteins are localized in the branch domain. Currently, the mechanisms and cellular machinery involved in biogenesis of the PAM are largely unknown. Here, we identify an EXO70I protein present exclusively in plants forming AM symbiosis. Medicago truncatula exo70i mutants are unable to support normal arbuscule development, and incorporation of two PAM-resident ABC transporters, STR and STR2, is limited. During arbuscule branching, EXO70I is located in spatially restricted zones adjacent to the PAM around the arbuscule hyphal tips where it interacts with Vapyrin, a plant-specific protein required for arbuscule development. We conclude that EXO70I provides a specific exocytotic capacity necessary for development of the main functional sub-domain of the PAM. Furthermore, in contrast to other eukaryotes, plant EXO70s have evolved distinct specificities and interaction partners to fulfill their specialized secretory requirements.
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Affiliation(s)
- Xinchun Zhang
- Boyce Thompson Institute for Plant Research, 533 Tower Road, Ithaca, NY 14853, USA
| | - Nathan Pumplin
- Boyce Thompson Institute for Plant Research, 533 Tower Road, Ithaca, NY 14853, USA; Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA
| | - Sergey Ivanov
- Boyce Thompson Institute for Plant Research, 533 Tower Road, Ithaca, NY 14853, USA
| | - Maria J Harrison
- Boyce Thompson Institute for Plant Research, 533 Tower Road, Ithaca, NY 14853, USA.
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91
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Chaudhari P, Ahmed B, Joly DL, Germain H. Effector biology during biotrophic invasion of plant cells. Virulence 2015; 5:703-9. [PMID: 25513771 PMCID: PMC4189876 DOI: 10.4161/viru.29652] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Several obligate biotrophic phytopathogens, namely oomycetes and fungi, invade and feed on living plant cells through specialized structures known as haustoria. Deploying an arsenal of secreted proteins called effectors, these pathogens balance their parasitic propagation by subverting plant immunity without sacrificing host cells. Such secreted proteins, which are thought to be delivered by haustoria, conceivably reprogram host cells and instigate structural modifications, in addition to the modulation of various cellular processes. As effectors represent tools to assist disease resistance breeding, this short review provides a bird’s eye view on the relationship between the virulence function of effectors and their subcellular localization in host cells.
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Affiliation(s)
- Prateek Chaudhari
- a Groupe de Recherche en Biologie Végétale; Département de Chimie, Biochimie et Physique; Université du Québec à Trois-Rivières; Trois-Rivières, QC Canada
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92
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Chi Y, Yang Y, Li G, Wang F, Fan B, Chen Z. Identification and characterization of a novel group of legume-specific, Golgi apparatus-localized WRKY and Exo70 proteins from soybean. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:3055-70. [PMID: 25805717 PMCID: PMC4449531 DOI: 10.1093/jxb/erv104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Many plant genes belong to families that arise from extensive proliferation and diversification allowing the evolution of functionally new proteins. Here we report the characterization of a group of proteins evolved from WRKY and exocyst complex subunit Exo70 proteins through fusion with a novel transmembrane (TM) domain in soybean (Glycine max). From the soybean genome, we identified a novel WRKY-related protein (GmWRP1) that contains a WRKY domain with no binding activity for W-box sequences. GFP fusion revealed that GmWRP1 was targeted to the Golgi apparatus through its N-terminal TM domain. Similar Golgi-targeting TM domains were also identified in members of a new subfamily of Exo70J proteins involved in vesicle trafficking. The novel TM domains are structurally most similar to the endosomal cytochrome b561 from birds and close homologues of GmWRP1 and GmEx070J proteins with the novel TM domain have only been identified in legumes. Transient expression of some GmExo70J proteins or the Golgi-targeting TM domain in tobacco altered the subcellular structures labelled by a fluorescent Golgi marker. GmWRP1 transcripts were detected at high levels in roots, flowers, pods, and seeds, and the expression levels of GmWRP1 and GmExo70J genes were elevated with increased age in leaves. The legume-specific, Golgi apparatus-localized GmWRP1 and GmExo70J proteins are probably involved in Golgi-mediated vesicle trafficking of biological molecules that are uniquely important to legumes.
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Affiliation(s)
- Yingjun Chi
- Department of Horticulture, Zijingang Campus, 866 Yuhangtang Road, Zhejiang University, Hangzhou, 310058, China
| | - Yan Yang
- Department of Horticulture, Zijingang Campus, 866 Yuhangtang Road, Zhejiang University, Hangzhou, 310058, China
| | - Guiping Li
- Department of Horticulture, Zijingang Campus, 866 Yuhangtang Road, Zhejiang University, Hangzhou, 310058, China
| | - Fei Wang
- Department of Botany and Plant Pathology, 915W. State Street, Purdue University, West Lafayette, IN 47907, USA
| | - Baofang Fan
- Department of Botany and Plant Pathology, 915W. State Street, Purdue University, West Lafayette, IN 47907, USA
| | - Zhixiang Chen
- Department of Horticulture, Zijingang Campus, 866 Yuhangtang Road, Zhejiang University, Hangzhou, 310058, China Department of Botany and Plant Pathology, 915W. State Street, Purdue University, West Lafayette, IN 47907, USA
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93
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Kulich I, Vojtíková Z, Glanc M, Ortmannová J, Rasmann S, Žárský V. Cell wall maturation of Arabidopsis trichomes is dependent on exocyst subunit EXO70H4 and involves callose deposition. PLANT PHYSIOLOGY 2015; 168:120-31. [PMID: 25767057 PMCID: PMC4424025 DOI: 10.1104/pp.15.00112] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Accepted: 03/10/2015] [Indexed: 05/22/2023]
Abstract
Arabidopsis (Arabidopsis thaliana) leaf trichomes are single-cell structures with a well-studied development, but little is understood about their function. Developmental studies focused mainly on the early shaping stages, and little attention has been paid to the maturation stage. We focused on the EXO70H4 exocyst subunit, one of the most up-regulated genes in the mature trichome. We uncovered EXO70H4-dependent development of the secondary cell wall layer, highly autofluorescent and callose rich, deposited only in the upper part of the trichome. The boundary is formed between the apical and the basal parts of mature trichome by a callose ring that is also deposited in an EXO70H4-dependent manner. We call this structure the Ortmannian ring (OR). Both the secondary cell wall layer and the OR are absent in the exo70H4 mutants. Ecophysiological aspects of the trichome cell wall thickening include interference with antiherbivore defense and heavy metal accumulation. Ultraviolet B light induces EXO70H4 transcription in a CONSTITUTIVE PHOTOMORPHOGENIC1-dependent way, resulting in stimulation of trichome cell wall thickening and the OR biogenesis. EXO70H4-dependent trichome cell wall hardening is a unique phenomenon, which may be conserved among a variety of the land plants. Our analyses support a concept that Arabidopsis trichome is an excellent model to study molecular mechanisms of secondary cell wall deposition.
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Affiliation(s)
- Ivan Kulich
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, 12844 Prague, Czech Republic (I.K., Z.V., M.G., J.O., V.Z.);Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 16502 Prague, Czech Republic (J.O., V.Z.); andDepartment of Ecology and Evolution, University of Lausanne, CH-1015 Lausanne, Switzerland (S.R.)
| | - Zdeňka Vojtíková
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, 12844 Prague, Czech Republic (I.K., Z.V., M.G., J.O., V.Z.);Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 16502 Prague, Czech Republic (J.O., V.Z.); andDepartment of Ecology and Evolution, University of Lausanne, CH-1015 Lausanne, Switzerland (S.R.)
| | - Matouš Glanc
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, 12844 Prague, Czech Republic (I.K., Z.V., M.G., J.O., V.Z.);Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 16502 Prague, Czech Republic (J.O., V.Z.); andDepartment of Ecology and Evolution, University of Lausanne, CH-1015 Lausanne, Switzerland (S.R.)
| | - Jitka Ortmannová
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, 12844 Prague, Czech Republic (I.K., Z.V., M.G., J.O., V.Z.);Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 16502 Prague, Czech Republic (J.O., V.Z.); andDepartment of Ecology and Evolution, University of Lausanne, CH-1015 Lausanne, Switzerland (S.R.)
| | - Sergio Rasmann
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, 12844 Prague, Czech Republic (I.K., Z.V., M.G., J.O., V.Z.);Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 16502 Prague, Czech Republic (J.O., V.Z.); andDepartment of Ecology and Evolution, University of Lausanne, CH-1015 Lausanne, Switzerland (S.R.)
| | - Viktor Žárský
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, 12844 Prague, Czech Republic (I.K., Z.V., M.G., J.O., V.Z.);Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 16502 Prague, Czech Republic (J.O., V.Z.); andDepartment of Ecology and Evolution, University of Lausanne, CH-1015 Lausanne, Switzerland (S.R.)
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94
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DeBlasio SL, Johnson R, Sweeney MM, Karasev A, Gray SM, MacCoss MJ, Cilia M. Potato leafroll virus structural proteins manipulate overlapping, yet distinct protein interaction networks during infection. Proteomics 2015; 15:2098-112. [PMID: 25787689 DOI: 10.1002/pmic.201400594] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 02/08/2015] [Accepted: 03/16/2015] [Indexed: 01/20/2023]
Abstract
Potato leafroll virus (PLRV) produces a readthrough protein (RTP) via translational readthrough of the coat protein amber stop codon. The RTP functions as a structural component of the virion and as a nonincorporated protein in concert with numerous insect and plant proteins to regulate virus movement/transmission and tissue tropism. Affinity purification coupled to quantitative MS was used to generate protein interaction networks for a PLRV mutant that is unable to produce the read through domain (RTD) and compared to the known wild-type PLRV protein interaction network. By quantifying differences in the protein interaction networks, we identified four distinct classes of PLRV-plant interactions: those plant and nonstructural viral proteins interacting with assembled coat protein (category I); plant proteins in complex with both coat protein and RTD (category II); plant proteins in complex with the RTD (category III); and plant proteins that had higher affinity for virions lacking the RTD (category IV). Proteins identified as interacting with the RTD are potential candidates for regulating viral processes that are mediated by the RTP such as phloem retention and systemic movement and can potentially be useful targets for the development of strategies to prevent infection and/or viral transmission of Luteoviridae species that infect important crop species.
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Affiliation(s)
- Stacy L DeBlasio
- Boyce Thompson Institute for Plant Research, Ithaca, NY, USA.,USDA-Agricultural Research Service, Ithaca, NY, USA
| | - Richard Johnson
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | | | - Alexander Karasev
- Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow, ID, USA
| | - Stewart M Gray
- USDA-Agricultural Research Service, Ithaca, NY, USA.,Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY, USA
| | - Michael J MacCoss
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Michelle Cilia
- Boyce Thompson Institute for Plant Research, Ithaca, NY, USA.,USDA-Agricultural Research Service, Ithaca, NY, USA.,Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY, USA
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95
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Park HC, Lee S, Park B, Choi W, Kim C, Lee S, Chung WS, Lee SY, Sabir J, Bressan RA, Bohnert HJ, Mengiste T, Yun DJ. Pathogen associated molecular pattern (PAMP)-triggered immunity is compromised under C-limited growth. Mol Cells 2015; 38:40-50. [PMID: 25387755 PMCID: PMC4314131 DOI: 10.14348/molcells.2015.2165] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 09/24/2013] [Accepted: 10/14/2014] [Indexed: 11/27/2022] Open
Abstract
In the interaction between plants and pathogens, carbon (C) resources provide energy and C skeletons to maintain, among many functions, the plant immune system. However, variations in C availability on pathogen associated molecular pattern (PAMP) triggered immunity (PTI) have not been systematically examined. Here, three types of starch mutants with enhanced susceptibility to Pseudomonas syringae pv. tomato DC3000 hrcC were examined for PTI. In a dark period-dependent manner, the mutants showed compromised induction of a PTI marker, and callose accumulation in response to the bacterial PAMP flagellin, flg22. In combination with weakened PTI responses in wild type by inhibition of the TCA cycle, the experiments determined the necessity of C-derived energy in establishing PTI. Global gene expression analyses identified flg22 responsive genes displaying C supply-dependent patterns. Nutrient recycling-related genes were regulated similarly by C-limitation and flg22, indicating re-arrangements of expression programs to redirect resources that establish or strengthen PTI. Ethylene and NAC transcription factors appear to play roles in these processes. Under C-limitation, PTI appears compromised based on suppression of genes required for continued biosynthetic capacity and defenses through flg22. Our results provide a foundation for the intuitive perception of the interplay between plant nutrition status and pathogen defense.
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Affiliation(s)
- Hyeong Cheol Park
- Division of Applied Life Science (BK21 Plus Program) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701,
Korea
- Bureau of Ecological Conservation Reseach, National Institute of Ecology, Seocheon 325-813,
Korea
| | - Shinyoung Lee
- Division of Applied Life Science (BK21 Plus Program) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701,
Korea
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907,
USA
| | - Bokyung Park
- Division of Applied Life Science (BK21 Plus Program) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701,
Korea
| | - Wonkyun Choi
- Division of Applied Life Science (BK21 Plus Program) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701,
Korea
- Bureau of Ecological Conservation Reseach, National Institute of Ecology, Seocheon 325-813,
Korea
| | - Chanmin Kim
- Division of Applied Life Science (BK21 Plus Program) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701,
Korea
| | - Sanghun Lee
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907,
USA
| | - Woo Sik Chung
- Division of Applied Life Science (BK21 Plus Program) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701,
Korea
| | - Sang Yeol Lee
- Division of Applied Life Science (BK21 Plus Program) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701,
Korea
| | - Jamal Sabir
- College of Science, King Abdulaziz University, Jeddah 21589,
Kingdom of Saudi Arabia
| | - Ray A. Bressan
- Division of Applied Life Science (BK21 Plus Program) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701,
Korea
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907,
USA
- College of Science, King Abdulaziz University, Jeddah 21589,
Kingdom of Saudi Arabia
| | - Hans J. Bohnert
- Division of Applied Life Science (BK21 Plus Program) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701,
Korea
- College of Science, King Abdulaziz University, Jeddah 21589,
Kingdom of Saudi Arabia
- Departments of Plant Biology and of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801,
USA
| | - Tesfaye Mengiste
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907,
USA
| | - Dae-Jin Yun
- Division of Applied Life Science (BK21 Plus Program) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701,
Korea
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96
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Zhao T, Rui L, Li J, Nishimura MT, Vogel JP, Liu N, Liu S, Zhao Y, Dangl JL, Tang D. A truncated NLR protein, TIR-NBS2, is required for activated defense responses in the exo70B1 mutant. PLoS Genet 2015; 11:e1004945. [PMID: 25617755 PMCID: PMC4305288 DOI: 10.1371/journal.pgen.1004945] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 12/09/2014] [Indexed: 11/18/2022] Open
Abstract
During exocytosis, the evolutionarily conserved exocyst complex tethers Golgi-derived vesicles to the target plasma membrane, a critical function for secretory pathways. Here we show that exo70B1 loss-of-function mutants express activated defense responses upon infection and express enhanced resistance to fungal, oomycete and bacterial pathogens. In a screen for mutants that suppress exo70B1 resistance, we identified nine alleles of TIR-NBS2 (TN2), suggesting that loss-of-function of EXO70B1 leads to activation of this nucleotide binding domain and leucine-rich repeat-containing (NLR)-like disease resistance protein. This NLR-like protein is atypical because it lacks the LRR domain common in typical NLR receptors. In addition, we show that TN2 interacts with EXO70B1 in yeast and in planta. Our study thus provides a link between the exocyst complex and the function of a 'TIR-NBS only' immune receptor like protein. Our data are consistent with a speculative model wherein pathogen effectors could evolve to target EXO70B1 to manipulate plant secretion machinery. TN2 could monitor EXO70B1 integrity as part of an immune receptor complex.
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Affiliation(s)
- Ting Zhao
- The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Lu Rui
- The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- Graduate School of Chinese Academy of Sciences, Beijing, China
| | - Juan Li
- The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Marc T. Nishimura
- Howard Hughes Medical Institute and Department of Biology, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - John P. Vogel
- Western Regional Research Center, United States Department of Agriculture, Agricultural Research Service, Albany, California, United States of America
| | - Na Liu
- The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- Graduate School of Chinese Academy of Sciences, Beijing, China
| | - Simu Liu
- The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- Graduate School of Chinese Academy of Sciences, Beijing, China
| | - Yaofei Zhao
- The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- Graduate School of Chinese Academy of Sciences, Beijing, China
| | - Jeffery L. Dangl
- Howard Hughes Medical Institute and Department of Biology, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Dingzhong Tang
- The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- * E-mail:
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97
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Cole RA, McInally SA, Fowler JE. Developmentally distinct activities of the exocyst enable rapid cell elongation and determine meristem size during primary root growth in Arabidopsis. BMC PLANT BIOLOGY 2014; 14:386. [PMID: 25551204 PMCID: PMC4302519 DOI: 10.1186/s12870-014-0386-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 12/15/2014] [Indexed: 05/20/2023]
Abstract
BACKGROUND Exocytosis is integral to root growth: trafficking components of systems that control growth (e.g., PIN auxin transport proteins) to the plasma membrane, and secreting materials that expand the cell wall to the apoplast. Spatiotemporal regulation of exocytosis in eukaryotes often involves the exocyst, an octameric complex that tethers selected secretory vesicles to specific sites on the plasma membrane and facilitates their exocytosis. We evaluated Arabidopsis lines with mutations in four exocyst components (SEC5, SEC8, EXO70A1 and EXO84B) to explore exocyst function in primary root growth. RESULTS The mutants have root growth rates that are 82% to 11% of wild-type. Even in lines with the most severe defects, the organization of the quiescent center and tissue layers at the root tips appears similar to wild-type, although meristematic, transition, and elongation zones are shorter. Reduced cell production rates in the mutants are due to the shorter meristems, but not to lengthened cell cycles. Additionally, mutants demonstrate reduced anisotropic cell expansion in the elongation zone, but not the meristematic zone, resulting in shorter mature cells that are similar in shape to wild-type. As expected, hypersensitivity to brefeldin A links the mutant root growth defect to altered vesicular trafficking. Several experimental approaches (e.g., dose-response measurements, localization of signaling components) failed to identify aberrant auxin or brassinosteroid signaling as a primary driver for reduced root growth in exocyst mutants. CONCLUSIONS The exocyst participates in two spatially distinct developmental processes, apparently by mechanisms not directly linked to auxin or brassinosteroid signaling pathways, to help establish root meristem size, and to facilitate rapid cell expansion in the elongation zone.
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Affiliation(s)
- Rex A Cole
- Botany and Plant Pathology, Oregon State University, 2082 Cordley Hall, Corvallis, 97331 OR USA
| | - Samantha A McInally
- Botany and Plant Pathology, Oregon State University, 2082 Cordley Hall, Corvallis, 97331 OR USA
| | - John E Fowler
- Botany and Plant Pathology, Oregon State University, 2082 Cordley Hall, Corvallis, 97331 OR USA
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98
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Dörmann P, Kim H, Ott T, Schulze-Lefert P, Trujillo M, Wewer V, Hückelhoven R. Cell-autonomous defense, re-organization and trafficking of membranes in plant-microbe interactions. THE NEW PHYTOLOGIST 2014; 204:815-22. [PMID: 25168837 DOI: 10.1111/nph.12978] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 07/16/2014] [Indexed: 05/07/2023]
Abstract
Plant cells dynamically change their architecture and molecular composition following encounters with beneficial or parasitic microbes, a process referred to as host cell reprogramming. Cell-autonomous defense reactions are typically polarized to the plant cell periphery underneath microbial contact sites, including de novo cell wall biosynthesis. Alternatively, host cell reprogramming converges in the biogenesis of membrane-enveloped compartments for accommodation of beneficial bacteria or invasive infection structures of filamentous microbes. Recent advances have revealed that, in response to microbial encounters, plasma membrane symmetry is broken, membrane tethering and SNARE complexes are recruited, lipid composition changes and plasma membrane-to-cytoskeleton signaling is activated, either for pre-invasive defense or for microbial entry. We provide a critical appraisal on recent studies with a focus on how plant cells re-structure membranes and the associated cytoskeleton in interactions with microbial pathogens, nitrogen-fixing rhizobia and mycorrhiza fungi.
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Affiliation(s)
- Peter Dörmann
- Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, D-53115, Bonn, Germany
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99
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Safavian D, Jamshed M, Sankaranarayanan S, Indriolo E, Samuel MA, Goring DR. High humidity partially rescues the Arabidopsis thaliana exo70A1 stigmatic defect for accepting compatible pollen. PLANT REPRODUCTION 2014; 27:121-7. [PMID: 24973977 DOI: 10.1007/s00497-014-0245-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 06/22/2014] [Indexed: 05/21/2023]
Abstract
We have previously proposed that Exo70A1 is required in the Brassicaceae stigma to control the early stages of pollen hydration and pollen tube penetration through the stigmatic surface, following compatible pollination. However, recent work has raised questions regarding Arabidopsis thaliana Exo70A1's expression in the stigma and its role in stigma receptivity to compatible pollen. Here, we verified the expression of Exo70A1 in stigmas from three Brassicaceae species and carefully re-examined Exo70A1's function in the stigmatic papillae. With previous studies showing that high relative humidity can rescue some pollination defects, essentially bypassing the control of pollen hydration by the Brassicaceae dry stigma, the effect of high humidity was investigated on pollinations with the Arabidopsis exo70A1-1 mutant. Pollinations under low relative humidity resulted in a complete failure of wild-type compatible pollen acceptance by the exo70A1-1 mutant stigma as we had previously seen. However, high relative humidity resulted in a partial rescue of the exo70A1-1 stigmatic papillar defect resulting is some wild-type compatible pollen acceptance and seed set. Thus, these results reaffirmed Exo70A1's proposed role in the stigma regulating compatible pollen hydration and pollen tube entry and demonstrate that high relative humidity can partially bypass these functions.
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Affiliation(s)
- Darya Safavian
- Department of Cell and Systems Biology, University of Toronto, Toronto, M5S 3B2, Canada
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100
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Pizarro L, Norambuena L. Regulation of protein trafficking: posttranslational mechanisms and the unexplored transcriptional control. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 225:24-33. [PMID: 25017156 DOI: 10.1016/j.plantsci.2014.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/30/2014] [Accepted: 05/02/2014] [Indexed: 05/29/2023]
Abstract
Endomembrane protein trafficking assures protein location through the endocytic and secretory routes. Trafficking pathways are diverse, depending on the proteins being trafficked, the final destination as well as their itinerary. Trafficking pathways are operated by machineries composed of a set of coordinately acting factors that transport proteins between compartments. Different machineries participate in each protein trafficking pathway, providing specificity and accuracy. Changes in the activity and abundance of trafficking proteins regulate protein flux. The preponderance of one pathway over another regulates protein location and relocation. Cellular requirements change during different processes and in response to stimuli; modulation of trafficking mechanisms must relocate proteins or alternatively increase/decrease the targeting rate of certain proteins. Conventionally, protein trafficking modulation has been explained as posttranslational modification of components of the relevant trafficking machinery. However, trafficking components are also transcriptionally regulated and several reports support that this regulation can modulate protein trafficking as well. This transcriptional modulation has an impact on plant physiology, and is a critical and fundamental mechanism. This scenario suggests a determinant mechanism that must be considered in the endomembrane protein trafficking research field.
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Affiliation(s)
- Lorena Pizarro
- Plant Molecular Biology Laboratory, Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile
| | - Lorena Norambuena
- Plant Molecular Biology Laboratory, Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile.
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