1
|
Wu Y, Liu N, Zheng C, Li D, Li S, Wu J, Zhao S. Insights into the Complexity and Functionality of Plant Virus Protein Phosphorylation. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:598-610. [PMID: 38814574 DOI: 10.1094/mpmi-04-24-0034-cr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
Phosphorylation, the most extensive and pleiotropic form of protein posttranslation modification, is central to cellular signal transduction. Throughout the extensive co-evolution of plant hosts and viruses, modifications to phosphorylation have served multiple purposes. Such modifications highlight the evolutionary trajectories of viruses and their hosts, with pivotal roles in regulation and refinement of host-virus interactions. In plant hosts, protein phosphorylation orchestrates immune responses, enhancing the activities of defense-related proteins such as kinases and transcription factors, thereby strengthening pathogen resistance in plants. Moreover, phosphorylation influences the interactions between host and viral proteins, altering viral spread and replication within host plants. In the context of plant viruses, protein phosphorylation controls key aspects of the infection cycle, including viral protein functionality and the interplay between viruses and host plant cells, leading to effects on viral accumulation and dissemination within plant tissues. Explorations of the nuances of protein phosphorylation in plant hosts and their interactions with viruses are particularly important. This review provides a systematic summary of the biological roles of the proteins of plant viruses carrying diverse genomes in regulating infection and host responses through changes in the phosphorylation status. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
Collapse
Affiliation(s)
- Yuansheng Wu
- Vector-borne Virus Research Center, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Na Liu
- Vector-borne Virus Research Center, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Chengxu Zheng
- Vector-borne Virus Research Center, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Dongyuan Li
- Vector-borne Virus Research Center, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shanshan Li
- Vector-borne Virus Research Center, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jianguo Wu
- Vector-borne Virus Research Center, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shanshan Zhao
- Vector-borne Virus Research Center, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| |
Collapse
|
2
|
Pouresmaeil M, Dall'Ara M, Salvato M, Turri V, Ratti C. Cauliflower mosaic virus: Virus-host interactions and its uses in biotechnology and medicine. Virology 2023; 580:112-119. [PMID: 36812696 DOI: 10.1016/j.virol.2023.02.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/14/2023] [Accepted: 02/15/2023] [Indexed: 02/19/2023]
Abstract
Cauliflower mosaic virus (CaMV) was the first discovered plant virus with genomic DNA that uses reverse transcriptase for replication. The CaMV 35S promoter is a constitutive promoter and thus, an attractive driver of gene expression in plant biotechnology. It is used in most transgenic crops to activate foreign genes which have been artificially inserted into the host plant. In the last century, producing food for the world's population while preserving the environment and human health is the main topic of agriculture. The damage caused by viral diseases has a significant negative economic impact on agriculture, and disease control is based on two strategies: immunization and prevention to contain virus spread, so correct identification of plant viruses is important for disease management. Here, we discuss CaMV from different aspects: taxonomy, structure and genome, host plants and symptoms, transmission and pathogenicity, prevention, control and application in biotechnology as well as in medicine. Also, we calculated the CAI index for three ORFs IV, V, and VI of the CaMV virus in host plants, the results of which can be used in the discussion of gene transfer or antibody production to identify the CaMV.
Collapse
Affiliation(s)
- Mahin Pouresmaeil
- Department of Biotechnology, Faculty of Agriculture, Azarbijan Shahid Madani University, Tabriz, Iran.
| | - Mattia Dall'Ara
- Department of Agricultural and Food Sciences, School of Agriculture and Veterinary Medicine, University of Bologna, 40127, Bologna, Italy
| | - Maria Salvato
- University of Maryland, Department of Veterinary Medicine, College Park, MD, 20742, USA
| | - Valentina Turri
- Healthcare Direction, Istituto Scientifico Romagnolo per Lo Studio e La Cura Dei Tumori, IRCCS, 47014, Meldola, FC, Italy
| | - Claudio Ratti
- Department of Agricultural and Food Sciences, School of Agriculture and Veterinary Medicine, University of Bologna, 40127, Bologna, Italy
| |
Collapse
|
3
|
Wang G, Gao G, Yang X, Yang X, Ma P. Casein kinase CK2 structure and activities in plants. JOURNAL OF PLANT PHYSIOLOGY 2022; 276:153767. [PMID: 35841742 DOI: 10.1016/j.jplph.2022.153767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/10/2022] [Accepted: 07/10/2022] [Indexed: 06/15/2023]
Abstract
Casein kinase CK2 is a highly conserved serine/threonine protein kinase and exists in all eukaryotes. It has been demonstrated to be widely involved in the biological processes of plants. The CK2 holoenzyme is a heterotetramer consisting of two catalytic subunits (α and/or α') and two regulatory subunits (β). CK2 in plants is generally encoded by multiple genes, with monomeric and oligomeric forms present in the tissue. Various subunit genes of CK2 have been cloned and characterized from Arabidopsis thaliana, tobacco, maize, wheat, tomato, and other plants. This paper reviews the structural features of CK2, provides a clear classification of its physiological functions and mechanisms of action, and elaborates on the regulation of CK2 activity to provide a knowledge base for subsequent studies of CK2 in plants.
Collapse
Affiliation(s)
- Guanfeng Wang
- College of Life Sciences, Northwest A&F University, Yangling, 712100, China
| | - Geling Gao
- College of Life Sciences, Northwest A&F University, Yangling, 712100, China
| | - Xiangna Yang
- College of Life Sciences, Northwest A&F University, Yangling, 712100, China
| | - Xiangdong Yang
- Institute of Agricultural Biotechnology, Jilin Academy of Agricultural Sciences, Changchun, 130033, China.
| | - Pengda Ma
- College of Life Sciences, Northwest A&F University, Yangling, 712100, China.
| |
Collapse
|
4
|
Zhuang X, Guo X, Gu T, Xu X, Qin L, Xu K, He Z, Zhang K. Phosphorylation of plant virus proteins: Analysis methods and biological functions. Front Microbiol 2022; 13:935735. [PMID: 35958157 PMCID: PMC9360750 DOI: 10.3389/fmicb.2022.935735] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 06/28/2022] [Indexed: 11/13/2022] Open
Abstract
Phosphorylation is one of the most extensively investigated post-translational modifications that orchestrate a variety of cellular signal transduction processes. The phosphorylation of virus-encoded proteins plays an important regulatory role in the infection cycle of such viruses in plants. In recent years, molecular mechanisms underlying the phosphorylation of plant viral proteins have been widely studied. Based on recent publications, our study summarizes the phosphorylation analyses of plant viral proteins and categorizes their effects on biological functions according to the viral life cycle. This review provides a theoretical basis for elucidating the molecular mechanisms of viral infection. Furthermore, it deepens our understanding of the biological functions of phosphorylation in the interactions between plants and viruses.
Collapse
Affiliation(s)
- Xinjian Zhuang
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Xiao Guo
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Tianxiao Gu
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Xiaowei Xu
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Lang Qin
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Kai Xu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Zhen He
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Kun Zhang
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China,Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China,*Correspondence: Kun Zhang, ;
| |
Collapse
|
5
|
Hyodo K, Okuno T. Hijacking of host cellular components as proviral factors by plant-infecting viruses. Adv Virus Res 2020; 107:37-86. [PMID: 32711734 DOI: 10.1016/bs.aivir.2020.04.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Plant viruses are important pathogens that cause serious crop losses worldwide. They are obligate intracellular parasites that commandeer a wide array of proteins, as well as metabolic resources, from infected host cells. In the past two decades, our knowledge of plant-virus interactions at the molecular level has exploded, which provides insights into how plant-infecting viruses co-opt host cellular machineries to accomplish their infection. Here, we review recent advances in our understanding of how plant viruses divert cellular components from their original roles to proviral functions. One emerging theme is that plant viruses have versatile strategies that integrate a host factor that is normally engaged in plant defense against invading pathogens into a viral protein complex that facilitates viral infection. We also highlight viral manipulation of cellular key regulatory systems for successful virus infection: posttranslational protein modifications for fine control of viral and cellular protein dynamics; glycolysis and fermentation pathways to usurp host resources, and ion homeostasis to create a cellular environment that is beneficial for viral genome replication. A deeper understanding of viral-infection strategies will pave the way for the development of novel antiviral strategies.
Collapse
Affiliation(s)
- Kiwamu Hyodo
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, Japan.
| | - Tetsuro Okuno
- Department of Plant Life Science, Faculty of Agriculture, Ryukoku University, Otsu, Shiga, Japan
| |
Collapse
|
6
|
Hervás M, Navajas R, Chagoyen M, García JA, Martínez-Turiño S. Phosphorylation-Related Crosstalk Between Distant Regions of the Core Region of the Coat Protein Contributes to Virion Assembly of Plum Pox Virus. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:653-667. [PMID: 31859600 DOI: 10.1094/mpmi-10-19-0305-r] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Eukaryotic proteins are often targets of posttranslational modifications (PTMs). Capsid protein (CP) of plum pox virus (PPV), a member of genus Potyvirus, has been reported to be prone to phosphorylation in four serines at the N-terminal region. CP phosphorylation has been proposed to influence PPV infection by regulating CP accumulation in coordination with a second PTM, O-GlcNAcylation. In this study, a further proteomic characterization of PPV CP phosphorylation revealed additional phospho-targets, thus evidencing even greater complexity of the network of PTMs affecting this protein. In particular, two new phosphorylation targets, T254 and T313, at protein distal core, appear to be highly relevant for infection. Although abolishing phosphorylation at these positions does not have a severe effect on infectivity or viral accumulation, phospho-mimicking at either of these targets disrupts cell-to-cell movement. Strand-specific reverse transcription-quantitative PCR analysis and fractionation by centrifugation in a continuous sucrose gradient enabled us to conclude that such a deleterious effect is not related to failures in replication but is a consequence of inaccurate virion assembly. The analysis of spontaneous compensatory mutations at the CP core identified in a multiple phospho-mimicking mutant disclosed a functional dialogue between distant phospho-targets, which was further supported by an in silico PPV virion model, built on the watermelon mosaic virus atomic structure. Therefore, whereas joint and opposite action of O-GlcNAcylation and phosphorylation at the N-terminal disordered protrusion of CP appears to regulate protein stability, we propose that phosphorylations at the core region control assembly and disassembly of viral particles.
Collapse
Affiliation(s)
- Marta Hervás
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología (CNB-CSIC), Campus Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Rosana Navajas
- Proteomics Unit, CNB-CSIC, ProteoRed ISCIII, Madrid 28049, Spain
| | - Mónica Chagoyen
- Computational Systems Biology Group, CNB-CSIC, Madrid 28049, Spain
| | - Juan Antonio García
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología (CNB-CSIC), Campus Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Sandra Martínez-Turiño
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología (CNB-CSIC), Campus Universidad Autónoma de Madrid, Madrid 28049, Spain
| |
Collapse
|
7
|
Paudel DB, Sanfaçon H. Exploring the Diversity of Mechanisms Associated With Plant Tolerance to Virus Infection. FRONTIERS IN PLANT SCIENCE 2018; 9:1575. [PMID: 30450108 PMCID: PMC6224807 DOI: 10.3389/fpls.2018.01575] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/09/2018] [Indexed: 05/17/2023]
Abstract
Tolerance is defined as an interaction in which viruses accumulate to some degree without causing significant loss of vigor or fitness to their hosts. Tolerance can be described as a stable equilibrium between the virus and its host, an interaction in which each partner not only accommodate trade-offs for survival but also receive some benefits (e.g., protection of the plant against super-infection by virulent viruses; virus invasion of meristem tissues allowing vertical transmission). This equilibrium, which would be associated with little selective pressure for the emergence of severe viral strains, is common in wild ecosystems and has important implications for the management of viral diseases in the field. Plant viruses are obligatory intracellular parasites that divert the host cellular machinery to complete their infection cycle. Highjacking/modification of plant factors can affect plant vigor and fitness. In addition, the toxic effects of viral proteins and the deployment of plant defense responses contribute to the induction of symptoms ranging in severity from tissue discoloration to malformation or tissue necrosis. The impact of viral infection is also influenced by the virulence of the specific virus strain (or strains for mixed infections), the host genotype and environmental conditions. Although plant resistance mechanisms that restrict virus accumulation or movement have received much attention, molecular mechanisms associated with tolerance are less well-understood. We review the experimental evidence that supports the concept that tolerance can be achieved by reaching the proper balance between plant defense responses and virus counter-defenses. We also discuss plant translation repression mechanisms, plant protein degradation or modification pathways and viral self-attenuation strategies that regulate the accumulation or activity of viral proteins to mitigate their impact on the host. Finally, we discuss current progress and future opportunities toward the application of various tolerance mechanisms in the field.
Collapse
Affiliation(s)
- Dinesh Babu Paudel
- Department of Botany, The University of British Columbia, Vancouver, BC, Canada
| | - Hélène Sanfaçon
- Summerland Research and Development Centre, Agriculture and Agri-Food Canada, Summerland, BC, Canada
| |
Collapse
|
8
|
Martínez‐Turiño S, Pérez JDJ, Hervás M, Navajas R, Ciordia S, Udeshi ND, Shabanowitz J, Hunt DF, García JA. Phosphorylation coexists with O-GlcNAcylation in a plant virus protein and influences viral infection. MOLECULAR PLANT PATHOLOGY 2018; 19:1427-1443. [PMID: 29024291 PMCID: PMC5895533 DOI: 10.1111/mpp.12626] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 09/29/2017] [Accepted: 10/09/2017] [Indexed: 06/07/2023]
Abstract
Phosphorylation and O-GlcNAcylation are two widespread post-translational modifications (PTMs), often affecting the same eukaryotic target protein. Plum pox virus (PPV) is a member of the genus Potyvirus which infects a wide range of plant species. O-GlcNAcylation of the capsid protein (CP) of PPV has been studied extensively, and some evidence of CP phosphorylation has also been reported. Here, we use proteomics analyses to demonstrate that PPV CP is phosphorylated in vivo at the N-terminus and the beginning of the core region. In contrast with the 'yin-yang' mechanism that applies to some mammalian proteins, PPV CP phosphorylation affects residues different from those that are O-GlcNAcylated (serines Ser-25, Ser-81, Ser-101 and Ser-118). Our findings show that PPV CP can be concurrently phosphorylated and O-GlcNAcylated at nearby residues. However, an analysis using a differential proteomics strategy based on iTRAQ (isobaric tags for relative and absolute quantitation) showed a significant enhancement of phosphorylation at Ser-25 in virions recovered from O-GlcNAcylation-deficient plants, suggesting that crosstalk between O-GlcNAcylation and phosphorylation in PPV CP takes place. Although the preclusion of phosphorylation at the four identified phosphotarget sites only had a limited impact on viral infection, the mimicking of phosphorylation prevents PPV infection in Prunus persica and weakens infection in Nicotiana benthamiana and other herbaceous hosts, prompting the emergence of potentially compensatory second mutations. We postulate that the joint action of phosphorylation and O-GlcNAcylation in the N-proximal segment of CP allows a fine-tuning of protein stability, providing the amount of CP required in each step of viral infection.
Collapse
Affiliation(s)
- Sandra Martínez‐Turiño
- Department of Plant Molecular GeneticsCentro Nacional de Biotecnología (CNB‐CSIC), Campus Universidad Autónoma de MadridMadrid 28049Spain
| | - José De Jesús Pérez
- Department of Plant Molecular GeneticsCentro Nacional de Biotecnología (CNB‐CSIC), Campus Universidad Autónoma de MadridMadrid 28049Spain
- Present address:
División de Biología MolecularInstituto Potosino de Investigación Científica y Tecnológica A.C.Camino a la Presa San José 2055San Luis PotosíSLPMéxico
| | - Marta Hervás
- Department of Plant Molecular GeneticsCentro Nacional de Biotecnología (CNB‐CSIC), Campus Universidad Autónoma de MadridMadrid 28049Spain
| | - Rosana Navajas
- Proteomics UnitCentro Nacional de Biotecnología (CNB‐CSIC), ProteoRed ISCIIIMadrid 28049Spain
| | - Sergio Ciordia
- Proteomics UnitCentro Nacional de Biotecnología (CNB‐CSIC), ProteoRed ISCIIIMadrid 28049Spain
| | - Namrata D. Udeshi
- Department of ChemistryUniversity of VirginiaCharlottesvilleVA 22904USA
- Present address:
Proteomics Platform, The Broad Institute of MIT and Harvard, 7 Cambridge Center, Room 5033CambridgeMA 02142USA
| | | | - Donald F. Hunt
- Department of ChemistryUniversity of VirginiaCharlottesvilleVA 22904USA
| | - Juan Antonio García
- Department of Plant Molecular GeneticsCentro Nacional de Biotecnología (CNB‐CSIC), Campus Universidad Autónoma de MadridMadrid 28049Spain
| |
Collapse
|
9
|
Schoelz JE, Leisner S. Setting Up Shop: The Formation and Function of the Viral Factories of Cauliflower mosaic virus. FRONTIERS IN PLANT SCIENCE 2017; 8:1832. [PMID: 29163571 PMCID: PMC5670102 DOI: 10.3389/fpls.2017.01832] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/10/2017] [Indexed: 05/23/2023]
Abstract
Similar to cells, viruses often compartmentalize specific functions such as genome replication or particle assembly. Viral compartments may contain host organelle membranes or they may be mainly composed of viral proteins. These compartments are often termed: inclusion bodies (IBs), viroplasms or viral factories. The same virus may form more than one type of IB, each with different functions, as illustrated by the plant pararetrovirus, Cauliflower mosaic virus (CaMV). CaMV forms two distinct types of IBs in infected plant cells, those composed mainly of the viral proteins P2 (which are responsible for transmission of CaMV by insect vectors) and P6 (required for viral intra-and inter-cellular infection), respectively. P6 IBs are the major focus of this review. Much of our understanding of the formation and function of P6 IBs comes from the analyses of their major protein component, P6. Over time, the interactions and functions of P6 have been gradually elucidated. Coupled with new technologies, such as fluorescence microscopy with fluorophore-tagged viral proteins, these data complement earlier work and provide a clearer picture of P6 IB formation. As the activities and interactions of the viral proteins have gradually been determined, the functions of P6 IBs have become clearer. This review integrates the current state of knowledge on the formation and function of P6 IBs to produce a coherent model for the activities mediated by these sophisticated virus-manufacturing machines.
Collapse
Affiliation(s)
- James E. Schoelz
- Division of Plant Sciences, University of Missouri, Columbia, MO, United States
| | - Scott Leisner
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States
| |
Collapse
|
10
|
Zhong X, Wang ZQ, Xiao R, Cao L, Wang Y, Xie Y, Zhou X. Mimic Phosphorylation of a βC1 Protein Encoded by TYLCCNB Impairs Its Functions as a Viral Suppressor of RNA Silencing and a Symptom Determinant. J Virol 2017; 91:e00300-17. [PMID: 28539450 PMCID: PMC5533934 DOI: 10.1128/jvi.00300-17] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/17/2017] [Indexed: 01/03/2023] Open
Abstract
Phosphorylation of the βC1 protein encoded by the betasatellite of tomato yellow leaf curl China virus (TYLCCNB-βC1) by SNF1-related protein kinase 1 (SnRK1) plays a critical role in defense of host plants against geminivirus infection in Nicotiana benthamiana However, how phosphorylation of TYLCCNB-βC1 impacts its pathogenic functions during viral infection remains elusive. In this study, we identified two additional tyrosine residues in TYLCCNB-βC1 that are phosphorylated by SnRK1. The effects of TYLCCNB-βC1 phosphorylation on its functions as a viral suppressor of RNA silencing (VSR) and a symptom determinant were investigated via phosphorylation mimic mutants in N. benthamiana plants. Mutations that mimic phosphorylation of TYLCCNB-βC1 at tyrosine 5 and tyrosine 110 attenuated disease symptoms during viral infection. The phosphorylation mimics weakened the ability of TYLCCNB-βC1 to reverse transcriptional gene silencing and to suppress posttranscriptional gene silencing and abolished its interaction with N. benthamiana ASYMMETRIC LEAVES 1 in N. benthamiana leaves. The mimic phosphorylation of TYLCCNB-βC1 had no impact on its protein stability, subcellular localization, or self-association. Our data establish an inhibitory effect of phosphorylation of TYLCCNB-βC1 on its pathogenic functions as a VSR and a symptom determinant and provide a mechanistic explanation of how SnRK1 functions as a host defense factor.IMPORTANCE Tomato yellow leaf curl China virus (TYLCCNV), which causes a severe yellow leaf curl disease in China, is a monopartite geminivirus associated with the betasatellite (TYLCCNB). TYLCCNB encodes a single pathogenicity protein, βC1 (TYLCCNB-βC1), which functions as both a viral suppressor of RNA silencing (VSR) and a symptom determinant. Here, we show that mimicking phosphorylation of TYLCCNB-βC1 weakens its ability to reverse transcriptional gene silencing, to suppress posttranscriptional gene silencing, and to interact with N. benthamiana ASYMMETRIC LEAVES 1. To our knowledge, this is the first report establishing an inhibitory effect of phosphorylation of TYLCCNB-βC1 on its pathogenic functions as both a VSR and a symptom determinant and to provide a mechanistic explanation of how SNF1-related protein kinase 1 acts as a host defense factor. These findings expand the scope of phosphorylation-mediated defense mechanisms and contribute to further understanding of plant defense mechanisms against geminiviruses.
Collapse
Affiliation(s)
- Xueting Zhong
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Zhan Qi Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Ruyuan Xiao
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Linge Cao
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Yaqin Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Yan Xie
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Xueping Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| |
Collapse
|
11
|
Zhao X, Wang X, Dong K, Zhang Y, Hu Y, Zhang X, Chen Y, Wang X, Han C, Yu J, Li D. Phosphorylation of Beet black scorch virus coat protein by PKA is required for assembly and stability of virus particles. Sci Rep 2015; 5:11585. [PMID: 26108567 PMCID: PMC4479801 DOI: 10.1038/srep11585] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/20/2015] [Indexed: 12/22/2022] Open
Abstract
Plant virus coat proteins (CPs) play a fundamental role in protection of genomic RNAs, virion assembly, and viral movement. Although phosphorylation of several CPs during virus infection have been reported, little information is available about CP phosphorylation of the spherical RNA plant viruses. Here, we demonstrate that the CP of Beet black scorch virus (BBSV), a member of the genus Necrovirus, can be phosphorylated at threonine-41 (T41) by cAMP-dependent protein kinase (PKA)-like kinase in vivo and in vitro. Mutant viruses containing a T41A non-phosphorylatable alanine substitution, and a T41E glutamic acid substitution to mimic threonine phosphorylation were able to replicate but were unable to move systemically in Nicotiana benthamiana. Interestingly, the T41A and T41E mutants generated unstable 17 nm virus-like particles that failed to package viral genomic (g) RNA, compared with wild-type BBSV with 30 nm virions during viral infection in N. benthamiana. Further analyses showed that the T41 mutations had little effect on the gRNA-binding activity of the CP. Therefore, we propose a model whereby CP phosphorylation plays an essential role in long-distance movement of BBSV that involves formation of stable virions.
Collapse
Affiliation(s)
- Xiaofei Zhao
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xiaoling Wang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Kai Dong
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yongliang Zhang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yue Hu
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xin Zhang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yanmei Chen
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xianbing Wang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Chenggui Han
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Jialin Yu
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Dawei Li
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| |
Collapse
|
12
|
Hung CJ, Huang YW, Liou MR, Lee YC, Lin NS, Meng M, Tsai CH, Hu CC, Hsu YH. Phosphorylation of coat protein by protein kinase CK2 regulates cell-to-cell movement of Bamboo mosaic virus through modulating RNA binding. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:1211-25. [PMID: 25025779 DOI: 10.1094/mpmi-04-14-0112-r] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
In this study, we investigated the fine regulation of cell-to-cell movement of Bamboo mosaic virus (BaMV). We report that the coat protein (CP) of BaMV is phosphorylated in planta at position serine 241 (S241), in a process involving Nicotiana benthamiana casein kinase 2α (NbCK2α). BaMV CP and NbCK2α colocalize at the plasmodesmata, suggesting that phosphorylation of BaMV may be involved in its movement. S241 was mutated to examine the effects of temporal and spatial dysregulation of phosphorylation on i) the interactions between CP and viral RNA and ii) the regulation of cell-to-cell movement. Replacement of S241 with alanine did not affect RNA binding affinity but moderately impaired cell-to-cell movement. A negative charge at position 241 reduced the ability of CP to bind RNA and severely interfered with cell-to-cell movement. Deletion of residues 240 to 242 increased the affinity of CP to viral RNA and dramatically impaired cell-to-cell movement. A threonine at position 241 changed the binding preference of CP toward genomic RNA and inhibited cell-to-cell movement. Together, these results reveal a fine regulatory mechanism for the cell-to-cell movement of BaMV, which involves the modulation of RNA binding affinity through appropriate phosphorylation of CP by NbCK2α.
Collapse
|
13
|
Shen W, Dallas MB, Goshe MB, Hanley-Bowdoin L. SnRK1 phosphorylation of AL2 delays Cabbage leaf curl virus infection in Arabidopsis. J Virol 2014. [PMID: 24990996 DOI: 10.1128/jvi.00671-14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
UNLABELLED Geminivirus AL2/C2 proteins play key roles in establishing infection and causing disease in their plant hosts. They are involved in viral gene expression, counter host defenses by suppressing transcriptional gene silencing, and interfere with the host signaling involved in pathogen resistance. We report here that begomovirus and curtovirus AL2/C2 proteins interact strongly with host geminivirus Rep-interacting kinases (GRIKs), which are upstream activating kinases of the protein kinase SnRK1, a global regulator of energy and nutrient levels in plants. We used an in vitro kinase system to show that GRIK-activated SnRK1 phosphorylates recombinant AL2/C2 proteins from several begomoviruses and to map the SnRK1 phosphorylation site to serine-109 in the AL2 proteins of two New World begomoviruses: Cabbage Leaf Curl Virus (CaLCuV) and Tomato mottle virus. A CaLCuV AL2 S109D phosphomimic mutation did not alter viral DNA levels in protoplast replication assays. In contrast, the phosphomimic mutant was delayed for symptom development and viral DNA accumulation during infection of Arabidopsis thaliana, demonstrating that SnRK1 contributes to host defenses against CaLCuV. Our observation that serine-109 is not conserved in all AL2/C2 proteins that are SnRK1 substrates in vitro suggested that phosphorylation of viral proteins by plant kinases contributes to the evolution of geminivirus-host interactions. IMPORTANCE Geminiviruses are single-stranded DNA viruses that cause serious diseases in many crops. Dicot-infecting geminiviruses carry genes that encode multifunctional AL2/C2 proteins that are essential for infection. However, it is not clear how AL2/C2 proteins are regulated. Here, we show that the host protein kinase SnRK1, a central regulator of energy balance and nutrient metabolism in plants, phosphorylates serine-109 in AL2 proteins of three subgroups of New World begomoviruses, resulting in a delay in viral DNA accumulation and symptom appearance. Our results support SnRK1's antiviral role and reveal a novel mechanism underlying this function. Phylogenetic analysis suggested that AL2 S109 evolved as begomoviruses migrated from the Old World to the New World and may have provided a selective advantage as begomoviruses adapted to a different environment and different plant hosts. This study provides new insights into the interaction of viral pathogens with their plant hosts at the level of viral protein modification by the host.
Collapse
Affiliation(s)
- Wei Shen
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Mary Beth Dallas
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Michael B Goshe
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Linda Hanley-Bowdoin
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
| |
Collapse
|
14
|
SnRK1 phosphorylation of AL2 delays Cabbage leaf curl virus infection in Arabidopsis. J Virol 2014; 88:10598-612. [PMID: 24990996 DOI: 10.1128/jvi.00761-14] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED Geminivirus AL2/C2 proteins play key roles in establishing infection and causing disease in their plant hosts. They are involved in viral gene expression, counter host defenses by suppressing transcriptional gene silencing, and interfere with the host signaling involved in pathogen resistance. We report here that begomovirus and curtovirus AL2/C2 proteins interact strongly with host geminivirus Rep-interacting kinases (GRIKs), which are upstream activating kinases of the protein kinase SnRK1, a global regulator of energy and nutrient levels in plants. We used an in vitro kinase system to show that GRIK-activated SnRK1 phosphorylates recombinant AL2/C2 proteins from several begomoviruses and to map the SnRK1 phosphorylation site to serine-109 in the AL2 proteins of two New World begomoviruses: Cabbage Leaf Curl Virus (CaLCuV) and Tomato mottle virus. A CaLCuV AL2 S109D phosphomimic mutation did not alter viral DNA levels in protoplast replication assays. In contrast, the phosphomimic mutant was delayed for symptom development and viral DNA accumulation during infection of Arabidopsis thaliana, demonstrating that SnRK1 contributes to host defenses against CaLCuV. Our observation that serine-109 is not conserved in all AL2/C2 proteins that are SnRK1 substrates in vitro suggested that phosphorylation of viral proteins by plant kinases contributes to the evolution of geminivirus-host interactions. IMPORTANCE Geminiviruses are single-stranded DNA viruses that cause serious diseases in many crops. Dicot-infecting geminiviruses carry genes that encode multifunctional AL2/C2 proteins that are essential for infection. However, it is not clear how AL2/C2 proteins are regulated. Here, we show that the host protein kinase SnRK1, a central regulator of energy balance and nutrient metabolism in plants, phosphorylates serine-109 in AL2 proteins of three subgroups of New World begomoviruses, resulting in a delay in viral DNA accumulation and symptom appearance. Our results support SnRK1's antiviral role and reveal a novel mechanism underlying this function. Phylogenetic analysis suggested that AL2 S109 evolved as begomoviruses migrated from the Old World to the New World and may have provided a selective advantage as begomoviruses adapted to a different environment and different plant hosts. This study provides new insights into the interaction of viral pathogens with their plant hosts at the level of viral protein modification by the host.
Collapse
|
15
|
Petukhova NV, Gasanova TV, Ivanov PA, Atabekov JG. High-level systemic expression of conserved influenza epitope in plants on the surface of rod-shaped chimeric particles. Viruses 2014; 6:1789-800. [PMID: 24755563 PMCID: PMC4014720 DOI: 10.3390/v6041789] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 03/10/2014] [Accepted: 04/01/2014] [Indexed: 12/02/2022] Open
Abstract
Recombinant viruses based on the cDNA copy of the tobacco mosaic virus (TMV) genome carrying different versions of the conserved M2e epitope from influenza virus A cloned into the coat protein (CP) gene were obtained and partially characterized by our group previously; cysteines in the human consensus M2e sequence were changed to serine residues. This work intends to show some biological properties of these viruses following plant infections. Agroinfiltration experiments on Nicotiana benthamiana confirmed the efficient systemic expression of M2e peptides, and two point amino acid substitutions in recombinant CPs significantly influenced the symptoms and development of viral infections. Joint expression of RNA interference suppressor protein p19 from tomato bushy stunt virus (TBSV) did not affect the accumulation of CP-M2e-ser recombinant protein in non-inoculated leaves. RT-PCR analysis of RNA isolated from either infected leaves or purified TMV-M2e particles proved the genetic stability of TMV‑based viral vectors. Immunoelectron microscopy of crude plant extracts demonstrated that foreign epitopes are located on the surface of chimeric virions. The rod‑shaped geometry of plant-produced M2e epitopes is different from the icosahedral or helical filamentous arrangement of M2e antigens on the carrier virus-like particles (VLP) described earlier. Thereby, we created a simple and efficient system that employs agrobacteria and plant viral vectors in order to produce a candidate broad-spectrum flu vaccine.
Collapse
Affiliation(s)
- Natalia V Petukhova
- Department of Virology, Lomonosov Moscow State University, Moscow 119991, Russia.
| | - Tatiana V Gasanova
- Department of Virology, Lomonosov Moscow State University, Moscow 119991, Russia.
| | - Peter A Ivanov
- Department of Virology, Lomonosov Moscow State University, Moscow 119991, Russia.
| | - Joseph G Atabekov
- Department of Virology, Lomonosov Moscow State University, Moscow 119991, Russia.
| |
Collapse
|
16
|
Cheng SF, Tsai MS, Huang CL, Huang YP, Chen IH, Lin NS, Hsu YH, Tsai CH, Cheng CP. Ser/Thr kinase-like protein of Nicotiana benthamiana is involved in the cell-to-cell movement of Bamboo mosaic virus. PLoS One 2013; 8:e62907. [PMID: 23646157 PMCID: PMC3639906 DOI: 10.1371/journal.pone.0062907] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 03/28/2013] [Indexed: 01/08/2023] Open
Abstract
To investigate the plant genes affected by Bamboo mosaic virus (BaMV) infection, we applied a cDNA-amplified fragment length polymorphism technique to screen genes with differential expression. A serine/threonine kinase-like (NbSTKL) gene of Nicotiana benthamiana is upregulated after BaMV infection. NbSTKL contains the homologous domain of Ser/Thr kinase. Knocking down the expression of NbSTKL by virus-induced gene silencing reduced the accumulation of BaMV in the inoculated leaves but not in the protoplasts. The spread of GFP-expressing BaMV in the inoculated leaves is also impeded by a reduced expression of NbSTKL. These data imply that NbSTKL facilitates the cell-to-cell movement of BaMV. The subcellular localization of NbSTKL is mainly on the cell membrane, which has been confirmed by mutagenesis and fractionation experiments. Combined with the results showing that active site mutation of NbSTKL does not change its subcellular localization but significantly affects BaMV accumulation, we conclude that NbSTKL may regulate BaMV movement on the cell membrane by its kinase-like activity. Moreover, the transient expression of NbSTKL does not significantly affect the accumulation of Cucumber mosaic virus (CMV) and Potato virus X (PVX); thus, NbSTKL might be a specific protein facilitating BaMV movement.
Collapse
Affiliation(s)
- Shun-Fang Cheng
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Meng-Shan Tsai
- Department of Life Sciences, Tzu Chi University, Hualien, Taiwan
| | - Chia-Lin Huang
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Ying-Ping Huang
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - I-Hsuan Chen
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Na-Sheng Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Nankang Taipei, Taiwan
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Ching-Hsiu Tsai
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Chi-Ping Cheng
- Department of Life Sciences, Tzu Chi University, Hualien, Taiwan
| |
Collapse
|
17
|
Coat proteins, host factors and plant viral replication. Curr Opin Virol 2012; 2:712-8. [DOI: 10.1016/j.coviro.2012.10.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 09/28/2012] [Accepted: 10/01/2012] [Indexed: 11/24/2022]
|
18
|
Dissmeyer N, Schnittger A. Use of phospho-site substitutions to analyze the biological relevance of phosphorylation events in regulatory networks. Methods Mol Biol 2011; 779:93-138. [PMID: 21837563 DOI: 10.1007/978-1-61779-264-9_6] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Biological information is often transmitted by phosphorylation cascades. However, the biological relevance of specific phosphorylation events is often difficult to determine. An invaluable tool to study the effect of kinases and/or phosphatases is the use of phospho- and dephospho-mimetic substitutions in the respective target proteins. Here, we present a generally applicable procedure of how to design, set-up, and carry out phosphorylation modulation experiments and subsequent monitoring of protein activities, taking -cyclin-dependent kinases (CDKs) as a case study. CDKs are key regulators of cell cycle progression in all eukaryotic cells. Consequently, CDKs are controlled at many levels and phosphorylation of CDKs -themselves is used to regulate their kinase activity. We describe in detail complementation experiments of a mutant in CDKA;1, the major cell cycle kinase in Arabidopsis, with phosphorylation-site variants of CDKA;1. CDKA;1 versions were generated either by mimicking a phosphorylated amino acid by replacing the respective residue with a negatively charged amino acid, e.g., aspartate or glutamate, or by mutating it to a non-phoshorylatable amino acid, such as alanine, valine, or phenylalanine. The genetic complementation studies were accompanied by the isolation of these kinase variants from plant extract and subsequent kinase assays to determine changes in their activity levels. This work allowed us to judge the importance of -posttranslational regulation of CDKA;1 in plants and has shown that the molecular mechanistics of CDK function are apparently conserved across the kingdoms. However, the regulatory wiring of CDKs is -strikingly different between plants, animals, and yeast.
Collapse
Affiliation(s)
- Nico Dissmeyer
- Leibniz Institute of Plant Biochemistry (IPB), Independent Junior Research Group on Protein Recognition and Degradation, Halle (Saale), Germany.
| | | |
Collapse
|
19
|
Tissue-spanning redox gradient-dependent assembly of native human papillomavirus type 16 virions. J Virol 2009; 83:10515-26. [PMID: 19656879 DOI: 10.1128/jvi.00731-09] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Papillomavirus capsids are composed of 72 pentamers reinforced through inter- and intrapentameric disulfide bonds. Recent research suggests that virus-like particles and pseudovirions (PsV) can undergo a redox-dependent conformational change involving disulfide interactions. We present here evidence that native virions exploit a tissue-spanning redox gradient that facilitates assembly events in the context of the complete papillomavirus life cycle. DNA encapsidation and infectivity titers are redox dependent in that they can be temporally modulated via treatment of organotypic cultures with oxidized glutathione. These data provide evidence that papillomavirus assembly and maturation is redox-dependent, utilizing multiple steps within both suprabasal and cornified layers.
Collapse
|
20
|
Kleinow T, Nischang M, Beck A, Kratzer U, Tanwir F, Preiss W, Kepp G, Jeske H. Three C-terminal phosphorylation sites in the Abutilon mosaic virus movement protein affect symptom development and viral DNA accumulation. Virology 2009; 390:89-101. [PMID: 19464722 DOI: 10.1016/j.virol.2009.04.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 04/09/2009] [Accepted: 04/23/2009] [Indexed: 01/02/2023]
Abstract
The Abutilon mosaic virus (AbMV, Geminiviridae) DNA B component encodes a movement protein (MP), which facilitates viral transport within plants and affects pathogenicity. The presence of phosphorylated serine and threonine residues was confirmed for MP expressed in yeast and Nicotiana benthamiana by comparative Western blot analysis using phospho-amino acid- and MP-specific immunodetection. Mass spectrometry of yeast-derived MP identified three phosphorylation sites located in the C-terminal domain (Thr-221, Ser-223 and Ser-250). To assess their functional relevance in plants, several point mutations were generated in the MP gene of DNA B, which replace Thr-221, Ser-223 and Ser-250, either singly or in combinations, with either an uncharged alanine or a phosphorylation-mimicking aspartate residue. When co-inoculated with DNA A, all mutants were infectious. In systemically infected plants the symptoms and/or viral DNA accumulation were significantly altered for several of the mutants.
Collapse
Affiliation(s)
- Tatjana Kleinow
- Institute of Biology, Department of Molecular Biology and Plant Virology, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany.
| | | | | | | | | | | | | | | |
Collapse
|