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Atallah OO, Yassin SM, Verchot J. New Insights into Hop Latent Viroid Detection, Infectivity, Host Range, and Transmission. Viruses 2023; 16:30. [PMID: 38257731 PMCID: PMC10819085 DOI: 10.3390/v16010030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/21/2023] [Accepted: 12/21/2023] [Indexed: 01/24/2024] Open
Abstract
Hop latent viroid (HLVd), a subviral pathogen from the family Pospiviroidae, is a major threat to the global cannabis industry and is the causative agent for "dudding disease". Infected plants can often be asymptomatic for a period of growth and then develop symptoms such as malformed and yellowing leaves, as well as stunted growth. During flowering, HLVd-infected plants show reduced levels of valuable metabolites. This study was undertaken to expand our basic knowledge of HLVd infectivity, transmission, and host range. HLVd-specific primers were used for RT-PCR detection in plant samples and were able to detect HLVd in as little as 5 picograms of total RNA. A survey of hemp samples obtained from a diseased production system proved sole infection of HLVd (72%) with no coexistence of hop stunt viroid. HLVd was infectious through successive passage assays using a crude sap or total RNA extract derived from infected hemp. HLVd was also highly transmissible through hemp seeds at rates of 58 to 80%. Host range assays revealed new hosts for HLVd: tomato, cucumber, chrysanthemum, Nicotiana benthamiana, and Arabidopsis thaliana (Col-0). Sequence analysis of 77 isolates revealed only 3 parsimony-informative sites, while 10 sites were detected among all HLVd isolates available in the GenBank. The phylogenetic relationship among HLVd isolates allowed for inferring two major clades based on the genetic distance. Our findings facilitate further studies on host-viroid interaction and viroid management.
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Affiliation(s)
| | | | - Jeanmarie Verchot
- Department of Plant Pathology & Microbiology, Texas A&M University, College Station, TX 77843, USA; (O.O.A.); (S.M.Y.)
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Yu M, Arai N, Ochiai T, Ohyama T. Expression and function of an S1-type nuclease in the digestive fluid of a sundew, Drosera adelae. ANNALS OF BOTANY 2023; 131:335-346. [PMID: 36546767 PMCID: PMC9992940 DOI: 10.1093/aob/mcac150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 12/11/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND AIMS Carnivorous plants trap and digest insects and similar-sized animals. Many studies have examined enzymes in the digestive fluids of these plants and have gradually unveiled the origins and gene expression of these enzymes. However, only a few attempts have been made at characterization of nucleases. This study aimed to reveal gene expression and the structural, functional and evolutionary characteristics of an S1-type nuclease (DAN1) in the digestive fluid of an Australian sundew, Drosera adelae, whose trap organ shows unique gene expression and related epigenetic regulation. METHODS Organ-specificity in Dan1 expression was examined using glandular tentacles, laminas, roots and inflorescences, and real-time PCR. The methylation status of the Dan1 promoter in each organ was clarified by bisulphite sequencing. The structural characteristics of DAN1 were studied by a comparison of primary structures of S1-type nucleases of three carnivorous and seven non-carnivorous plants. DAN1 was prepared using a cell-free protein synthesis system. Requirements for metal ions, optimum pH and temperature, and substrate preference were examined using conventional methods. KEY RESULTS Dan1 is exclusively expressed in the glandular tentacles and its promoter is almost completely unmethylated in all organs. This is in contrast to the S-like RNase gene da-I of Dr. adelae, which shows similar organ-specific expression, but is controlled by a promoter that is specifically unmethylated in the glandular tentacles. Comparison of amino acid sequences of S1-type nucleases identifies seven and three positions where amino acid residues are conserved only among the carnivorous plants and only among the non-carnivorous plants, respectively. DAN1 prefers a substrate RNA over DNA in the presence of Zn2+, Mn2+ or Ca2+ at an optimum pH of 4.0. CONCLUSIONS Uptake of phosphates from prey is suggested to be the main function of DAN1, which is very different from the known functions of S1-type nucleases. Evolution has modified the structure and expression of Dan1 to specifically function in the digestive fluid.
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Affiliation(s)
- Meng Yu
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Naoki Arai
- Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama-shi, Kanagawa 221-8686, Japan
| | - Tadahiro Ochiai
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Takashi Ohyama
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
- Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
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Adkar-Purushothama CR, Sano T, Perreault JP. Hop Latent Viroid: A Hidden Threat to the Cannabis Industry. Viruses 2023; 15:681. [PMID: 36992390 PMCID: PMC10053334 DOI: 10.3390/v15030681] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 02/25/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023] Open
Abstract
Hop latent viroid (HLVd) is the biggest concern for cannabis and hop growers worldwide. Although most HLVd-infected plants remain asymptomatic, research on hops has demonstrated a decrease in both the α-bitter acid and terpene content of hop cones, which affects their economic value. The HLVd-associated "dudding" or "duds" disease of cannabis was first reported in 2019 in California. Since then, the disease has become widespread in cannabis-growing facilities across North America. Although severe yield loss associated with duds disease has been recorded, little scientific information is available to growers in order to contain HLVd. Consequently, this review aims to summarise all of the scientific information available on HLVd so as to be able to understand the effect of HLVd on yield loss, cannabinoid content, terpene profile, disease management and inform crop protection strategies.
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Affiliation(s)
| | - Teruo Sano
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki 036-8561, Japan
| | - Jean-Pierre Perreault
- RNA Group, Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, PQ J1E 4K8, Canada
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Matoušek J, Steger G. The Splicing Variant TFIIIA-7ZF of Viroid-Modulated Transcription Factor IIIA Causes Physiological Irregularities in Transgenic Tobacco and Transient Somatic Depression of "Degradome" Characteristic for Developing Pollen. Cells 2022; 11:784. [PMID: 35269406 PMCID: PMC8909551 DOI: 10.3390/cells11050784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/20/2022] [Accepted: 02/21/2022] [Indexed: 02/06/2023] Open
Abstract
Viroids are small, non-coding, pathogenic RNAs with a significant ability of adaptation to several basic cellular processes in plants. TFIIIA-7ZF, a splicing variant of transcription factor IIIA, is involved in replication of nuclear-replicating viroids by DNA-dependent polymerase II. We overexpressed NbTFIIIA-7ZF from Nicotiana benthamiana in tobacco (Nicotiana tabacum) where it caused morphological and physiological deviations like plant stunting, splitting of leaf petioles, pistils or apexes, irregular branching of shoots, formation of double-blade leaves, deformation of main stems, and modification of glandular trichomes. Plant aging and senescence was dramatically delayed in transgenic lines. Factors potentially involved in viroid degradation and elimination in pollen were transiently depressed in transgenic leaves. This depressed "degradome" in young plants involved NtTudor S-like nuclease, dicers, argonoute 5, and pollen extracellular nuclease I showing expression in tobacco anthers and leaves. Analysis of the "degradome" in tobacco leaves transformed with either of two hop viroids confirmed modifications of the "degradome" and TFIIIA expression. Thus, the regulatory network connected to TFIIIA-7ZF could be involved in plant pathogenesis as well as in viroid adaptation to avoid its degradation. These results support the hypothesis on a significant impact of limited TFIIIA-7ZF on viroid elimination in pollen.
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Affiliation(s)
- Jaroslav Matoušek
- Biology Centre of the Czech Academy of Sciences, Department of Molecular Genetics, Institute of Plant Molecular Biology, Branišovská 31, 37005 České Budějovice, Czech Republic;
| | - Gerhard Steger
- Institutfür Pysikalische Biologie, Heinrich Heine University Düsseldorf, 40204 Düsseldorf, Germany
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Steinbachová L, Matoušek J, Steger G, Matoušková H, Radišek S, Honys D. Transformation of Seed Non-Transmissible Hop Viroids in Nicotiana benthamiana Causes Distortions in Male Gametophyte Development. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10112398. [PMID: 34834761 PMCID: PMC8624972 DOI: 10.3390/plants10112398] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/22/2021] [Accepted: 11/03/2021] [Indexed: 05/27/2023]
Abstract
Viroids are small, non-coding, parasitic RNAs that promote developmental distortions in sensitive plants. We analyzed pollen of Nicotiana benthamiana after infection and/or ectopic transformation with cDNAs of citrus bark cracking viroid (CBCVd), apple fruit crinkle viroid (AFCVd) and potato spindle tuber viroid (PSTVd) variant AS1. These viroids were seed non-transmissible in N. benthamiana. All viroids propagated to high levels in immature anthers similar to leaves, while their levels were drastically reduced by approximately 3.6 × 103, 800 and 59 times in mature pollen of CBCVd, AFCVd and PSTVd infected N. benthamiana, respectively, in comparison to leaves. These results suggest similar elimination processes during male gametophyte development as in the Nicotiana tabacum we presented in our previous study. Mature pollen of N. benthamiana showed no apparent defects in infected plants although all three viroids induced strong pathological symptoms on leaves. While Nicotiana species have naturally bicellular mature pollen, we noted a rare occurrence of mature pollen with three nuclei in CBCVd-infected N. benthamiana. Changes in the expression of ribosomal marker proteins in AFCVd-infected pollen were detected, suggesting some changes in pollen metabolism. N. benthamiana transformed with 35S-driven viroid cDNAs showed strong symptoms including defects in pollen development. A large number of aborted pollen (34% and 62%) and a slight increase of young pollen grains (8% and 15%) were found in mature pollen of AFCVd and CBCVd transformants, respectively, in comparison to control plants (3.9% aborted pollen and 0.3% young pollen). Moreover, pollen grains with malformed nuclei or trinuclear pollen were found in CBCVd-transformed plants. Our results suggest that "forcing" overexpression of seed non-transmissible viroid led to strong pollen pathogenesis. Viroid adaptation to pollen metabolism can be assumed as an important factor for viroid transmissibility through pollen and seeds.
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Affiliation(s)
- Lenka Steinbachová
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02 Prague 6, Czech Republic;
| | - Jaroslav Matoušek
- Biology Centre of the Czech Academy of Sciences, Department of Molecular Genetics, Institute of Plant Molecular Biology, Branišovská 31, 37005 České Budějovice, Czech Republic; (J.M.); (H.M.)
| | - Gerhard Steger
- Institut für Physikalische Biologie, Heinrich Heine University Düsseldorf, D-40204 Düsseldorf, Germany;
| | - Helena Matoušková
- Biology Centre of the Czech Academy of Sciences, Department of Molecular Genetics, Institute of Plant Molecular Biology, Branišovská 31, 37005 České Budějovice, Czech Republic; (J.M.); (H.M.)
| | - Sebastjan Radišek
- Slovenian Institute of Hop Research and Brewing, Cesta Žalskega tabora 2, SI-3310 Žalec, Slovenia;
| | - David Honys
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02 Prague 6, Czech Republic;
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Bradamante G, Mittelsten Scheid O, Incarbone M. Under siege: virus control in plant meristems and progeny. THE PLANT CELL 2021; 33:2523-2537. [PMID: 34015140 PMCID: PMC8408453 DOI: 10.1093/plcell/koab140] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 05/14/2021] [Indexed: 05/29/2023]
Abstract
In the arms race between plants and viruses, two frontiers have been utilized for decades to combat viral infections in agriculture. First, many pathogenic viruses are excluded from plant meristems, which allows the regeneration of virus-free plant material by tissue culture. Second, vertical transmission of viruses to the host progeny is often inefficient, thereby reducing the danger of viral transmission through seeds. Numerous reports point to the existence of tightly linked meristematic and transgenerational antiviral barriers that remain poorly understood. In this review, we summarize the current understanding of the molecular mechanisms that exclude viruses from plant stem cells and progeny. We also discuss the evidence connecting viral invasion of meristematic cells and the ability of plants to recover from acute infections. Research spanning decades performed on a variety of virus/host combinations has made clear that, beside morphological barriers, RNA interference (RNAi) plays a crucial role in preventing-or allowing-meristem invasion and vertical transmission. How a virus interacts with plant RNAi pathways in the meristem has profound effects on its symptomatology, persistence, replication rates, and, ultimately, entry into the host progeny.
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Affiliation(s)
- Gabriele Bradamante
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Ortrun Mittelsten Scheid
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Marco Incarbone
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
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Shrestha A, Mishra AK, Matoušek J, Steinbachová L, Potěšil D, Nath VS, Awasthi P, Kocábek T, Jakse J, Drábková LZ, Zdráhal Z, Honys D, Steger G. Integrated Proteo-Transcriptomic Analyses Reveal Insights into Regulation of Pollen Development Stages and Dynamics of Cellular Response to Apple Fruit Crinkle Viroid (AFCVd)-Infection in Nicotiana tabacum. Int J Mol Sci 2020; 21:E8700. [PMID: 33218043 PMCID: PMC7698868 DOI: 10.3390/ijms21228700] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/15/2020] [Accepted: 11/17/2020] [Indexed: 02/06/2023] Open
Abstract
Tobacco (Nicotiana tabacum) pollen is a well-suited model for studying many fundamental biological processes owing to its well-defined and distinct development stages. It is also one of the major agents involved in the transmission of infectious viroids, which is the primary mechanism of viroid pathogenicity in plants. However, some viroids are non-transmissible and may be possibly degraded or eliminated during the gradual process of pollen development maturation. The molecular details behind the response of developing pollen against the apple fruit crinkle viroid (AFCVd) infection and viroid eradication is largely unknown. In this study, we performed an integrative analysis of the transcriptome and proteome profiles to disentangle the molecular cascade of events governing the three pollen development stages: early bicellular pollen (stage 3, S3), late bicellular pollen (stage 5, S5), and 6 h-pollen tube (PT6). The integrated analysis delivered the molecular portraits of the developing pollen against AFCVd infection, including mechanistic insights into the viroid eradication during the last steps of pollen development. The isobaric tags for label-free relative quantification (iTRAQ) with digital gene expression (DGE) experiments led us to reliably identify subsets of 5321, 5286, and 6923 proteins and 64,033, 60,597, and 46,640 expressed genes in S3, S5, and PT6, respectively. In these subsets, 2234, 2108 proteins and 9207 and 14,065 mRNAs were differentially expressed in pairwise comparisons of three stages S5 vs. S3 and PT6 vs. S5 of control pollen in tobacco. Correlation analysis between the abundance of differentially expressed mRNAs (DEGs) and differentially expressed proteins (DEPs) in pairwise comparisons of three stages of pollen revealed numerous discordant changes in mRNA/protein pairs. Only a modest correlation was observed, indicative of divergent transcription, and its regulation and importance of post-transcriptional events in the determination of the fate of early and late pollen development in tobacco. The functional and enrichment analysis of correlated DEGs/DEPs revealed the activation in pathways involved in carbohydrate metabolism, amino acid metabolism, lipid metabolism, and cofactor as well as vitamin metabolism, which points to the importance of these metabolic pathways in pollen development. Furthermore, the detailed picture of AFCVd-infected correlated DEGs/DEPs was obtained in pairwise comparisons of three stages of infected pollen. The AFCVd infection caused the modulation of several genes involved in protein degradation, nuclear transport, phytohormone signaling, defense response, and phosphorylation. Intriguingly, we also identified several factors including, DNA-dependent RNA-polymerase, ribosomal protein, Argonaute (AGO) proteins, nucleotide binding proteins, and RNA exonucleases, which may plausibly involve in viroid stabilization and eradication during the last steps of pollen development. The present study provides essential insights into the transcriptional and translational dynamics of tobacco pollen, which further strengthens our understanding of plant-viroid interactions and support for future mechanistic studies directed at delineating the functional role of candidate factors involved in viroid elimination.
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Affiliation(s)
- Ankita Shrestha
- Biology Centre, Czech Academy of Sciences, Department of Molecular Genetics, Institute of Plant Molecular Biology, Branišovská 31, 37005 České Budějovice, Czech Republic; (A.S.); (J.M.); (V.S.N.); (P.A.); (T.K.)
| | - Ajay Kumar Mishra
- Biology Centre, Czech Academy of Sciences, Department of Molecular Genetics, Institute of Plant Molecular Biology, Branišovská 31, 37005 České Budějovice, Czech Republic; (A.S.); (J.M.); (V.S.N.); (P.A.); (T.K.)
| | - Jaroslav Matoušek
- Biology Centre, Czech Academy of Sciences, Department of Molecular Genetics, Institute of Plant Molecular Biology, Branišovská 31, 37005 České Budějovice, Czech Republic; (A.S.); (J.M.); (V.S.N.); (P.A.); (T.K.)
| | - Lenka Steinbachová
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02 Prague 6-Lysolaje, Czech Republic; (L.S.); (L.Z.D.); (D.H.)
| | - David Potěšil
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic; (D.P.); (Z.Z.)
| | - Vishnu Sukumari Nath
- Biology Centre, Czech Academy of Sciences, Department of Molecular Genetics, Institute of Plant Molecular Biology, Branišovská 31, 37005 České Budějovice, Czech Republic; (A.S.); (J.M.); (V.S.N.); (P.A.); (T.K.)
| | - Praveen Awasthi
- Biology Centre, Czech Academy of Sciences, Department of Molecular Genetics, Institute of Plant Molecular Biology, Branišovská 31, 37005 České Budějovice, Czech Republic; (A.S.); (J.M.); (V.S.N.); (P.A.); (T.K.)
| | - Tomáš Kocábek
- Biology Centre, Czech Academy of Sciences, Department of Molecular Genetics, Institute of Plant Molecular Biology, Branišovská 31, 37005 České Budějovice, Czech Republic; (A.S.); (J.M.); (V.S.N.); (P.A.); (T.K.)
| | - Jernej Jakse
- Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia;
| | - Lenka Záveská Drábková
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02 Prague 6-Lysolaje, Czech Republic; (L.S.); (L.Z.D.); (D.H.)
| | - Zbyněk Zdráhal
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic; (D.P.); (Z.Z.)
| | - David Honys
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02 Prague 6-Lysolaje, Czech Republic; (L.S.); (L.Z.D.); (D.H.)
| | - Gerhard Steger
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, D-40204 Düsseldorf, Germany;
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Matoušek J, Steinbachová L, Drábková LZ, Kocábek T, Potěšil D, Mishra AK, Honys D, Steger G. Elimination of Viroids from Tobacco Pollen Involves a Decrease in Propagation Rate and an Increase of the Degradation Processes. Int J Mol Sci 2020; 21:E3029. [PMID: 32344786 PMCID: PMC7216239 DOI: 10.3390/ijms21083029] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/19/2020] [Accepted: 04/20/2020] [Indexed: 12/13/2022] Open
Abstract
Some viroids-single-stranded, non-coding, circular RNA parasites of plants-are not transmissible through pollen to seeds and to next generation. We analyzed the cause for the elimination of apple fruit crinkle viroid (AFCVd) and citrus bark cracking viroid (CBCVd) from male gametophyte cells of Nicotiana tabacum by RNA deep sequencing and molecular methods using infected and transformed tobacco pollen tissues at different developmental stages. AFCVd was not transferable from pollen to seeds in reciprocal pollinations, due to a complete viroid eradication during the last steps of pollen development and fertilization. In pollen, the viroid replication pathway proceeds with detectable replication intermediates, but is dramatically depressed in comparison to leaves. Specific and unspecific viroid degradation with some preference for (-) chains occurred in pollen, as detected by analysis of viroid-derived small RNAs, by quantification of viroid levels and by detection of viroid degradation products forming "comets" on Northern blots. The decrease of viroid levels during pollen development correlated with mRNA accumulation of several RNA-degrading factors, such as AGO5 nuclease, DICER-like and TUDOR S-like nuclease. In addition, the functional status of pollen, as a tissue with high ribosome content, could play a role during suppression of AFCVd replication involving transcription factors IIIA and ribosomal protein L5.
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Affiliation(s)
- Jaroslav Matoušek
- Biology Centre of the Czech Academy of Sciences, Department of Molecular Genetics, Institute of Plant Molecular Biology, Branišovská 31, 37005 České Budějovice, Czech Republic; (J.M.); (T.K.); (A.K.M.)
| | - Lenka Steinbachová
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02 Prague 6, Czech Republic; (L.S.); (L.Z.D.); (D.H.)
| | - Lenka Záveská Drábková
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02 Prague 6, Czech Republic; (L.S.); (L.Z.D.); (D.H.)
| | - Tomáš Kocábek
- Biology Centre of the Czech Academy of Sciences, Department of Molecular Genetics, Institute of Plant Molecular Biology, Branišovská 31, 37005 České Budějovice, Czech Republic; (J.M.); (T.K.); (A.K.M.)
| | - David Potěšil
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic;
| | - Ajay Kumar Mishra
- Biology Centre of the Czech Academy of Sciences, Department of Molecular Genetics, Institute of Plant Molecular Biology, Branišovská 31, 37005 České Budějovice, Czech Republic; (J.M.); (T.K.); (A.K.M.)
| | - David Honys
- Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02 Prague 6, Czech Republic; (L.S.); (L.Z.D.); (D.H.)
| | - Gerhard Steger
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, D-40204 Düsseldorf, Germany
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9
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Podzimek T, Přerovská T, Šantrůček J, Kovaľ T, Dohnálek J, Matoušek J, Lipovová P. N-glycosylation of tomato nuclease TBN1 produced in N. benthamiana and its effect on the enzyme activity. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 276:152-161. [PMID: 30348313 DOI: 10.1016/j.plantsci.2018.08.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 08/21/2018] [Accepted: 08/22/2018] [Indexed: 06/08/2023]
Abstract
A unique analysis of an enzyme activity versus structure modification of the tomato nuclease R-TBN1 is presented. R-TBN1, the non-specific nuclease belonging to the S1-P1 nuclease family, was recombinantly produced in N. benthamiana. The native structure is posttranslationally modified by N-glycosylation at three sites. In this work, it was found that this nuclease is modified by high-mannose type N-glycosylation with a certain degree of macro- and microheterogeneity. To monitor the role of N-glycosylation in its activity, hypo- and hyperglycosylated nuclease mutants, R-TBN1 digested by α-mannosidase, and R-TBN1 deglycosylated by PNGase F were prepared. Deglycosylated R-TBN1 and mutant N94D/N112D were virtually inactive. Compared to R-TBN1 wt, both N94D and N112D mutants showed about 60% and 10% of the activity, respectively, while the N186D, D36S, and D36S/E104 N mutants were equally or even more active than R-TBN1 wt. The partial demannosylation of R-TBN1 did not affect the nuclease activity; moreover, a little shift in substrate specificity was observed. The results show two facts: 1) which sites must be occupied by a glycan for the proper folding and stability and 2) how N. benthamiana glycosylates the foreign nuclease. At the same time, the modifications can be interesting in designing the nuclease activity or specificity through its glycosylation.
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Affiliation(s)
- Tomáš Podzimek
- University of Chemical Technology Prague, Technická 3, Prague 6, 166 28, Czech Republic.
| | - Tereza Přerovská
- University of Chemical Technology Prague, Technická 3, Prague 6, 166 28, Czech Republic
| | - Jiří Šantrůček
- University of Chemical Technology Prague, Technická 3, Prague 6, 166 28, Czech Republic
| | - Tomáš Kovaľ
- Institute of Biotechnology of the Czech Academy of Sciences, v. v. i., Biocev, Průmyslová 595, 252 50, Vestec, Czech Republic
| | - Jan Dohnálek
- Institute of Biotechnology of the Czech Academy of Sciences, v. v. i., Biocev, Průmyslová 595, 252 50, Vestec, Czech Republic
| | - Jaroslav Matoušek
- Biology Centre, ASCR v.v.i., Institute of Plant Molecular Biology, Branišovská 32, 370 05, České Budějovice, Czech Republic
| | - Petra Lipovová
- University of Chemical Technology Prague, Technická 3, Prague 6, 166 28, Czech Republic
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10
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Yanagisawa H, Matsushita Y. Differences in dynamics of horizontal transmission of Tomato planta macho viroid and Potato spindle tuber viroid after pollination with viroid-infected pollen. Virology 2018; 516:258-264. [PMID: 29425768 DOI: 10.1016/j.virol.2018.01.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 01/26/2018] [Accepted: 01/27/2018] [Indexed: 11/17/2022]
Abstract
For viroids, pollen transmission is an important transmission pathway to progeny seeds and new hosts. In the current study, we found that Tomato planta macho viroid (TPMVd)-but not Potato spindle tuber viroid (PSTVd)-was horizontally transmitted by pollen from petunia plants. Using tissue-printing hybridization to track the changes in viroid distribution after pollination, we noted that TPMVd was present in petunia stigma, styles, and eventually ovaries, whereas PSTVd was detected in the stigma and upper style but not the ovary. These findings suggest that horizontal transmission of viroids depends on the infection of the lower style and ovary during the elongation of pollen tubes after pollination. Additionally, TPMVd was transmitted horizontally, leading to systematic infection, when we used TPMVd-infected petunia pollen to pollinate the flowers of healthy tomato plants. Fertilization typically does not occur after heterologous pollination and thus likely is not required to accomplish horizontal transmission of viroids.
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Affiliation(s)
- Hironobu Yanagisawa
- Central Region Agricultural Research Center, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8666, Japan; The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate 020-8550, Japan.
| | - Yosuke Matsushita
- Institute of Vegetable and Floriculture Science, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8519, Japan.
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Koval T, Dohnálek J. Characteristics and application of S1–P1 nucleases in biotechnology and medicine. Biotechnol Adv 2018; 36:603-612. [DOI: 10.1016/j.biotechadv.2017.12.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 12/08/2017] [Accepted: 12/13/2017] [Indexed: 12/18/2022]
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Adkar-Purushothama CR, Brosseau C, Giguère T, Sano T, Moffett P, Perreault JP. Small RNA Derived from the Virulence Modulating Region of the Potato spindle tuber viroid Silences callose synthase Genes of Tomato Plants. THE PLANT CELL 2015; 27:2178-94. [PMID: 26290537 PMCID: PMC4568511 DOI: 10.1105/tpc.15.00523] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 07/23/2015] [Accepted: 07/31/2015] [Indexed: 05/20/2023]
Abstract
The tomato (Solanum lycopersicum) callose synthase genes CalS11-like and CalS12-like encode proteins that are essential for the formation of callose, a major component of pollen mother cell walls; these enzymes also function in callose formation during pathogen infection. This article describes the targeting of these callose synthase mRNAs by a small RNA derived from the virulence modulating region of two Potato spindle tuber viroid variants. More specifically, viroid infection of tomato plants resulted in the suppression of the target mRNAs up to 1.5-fold, depending on the viroid variant used and the gene targeted. The targeting of these mRNAs by RNA silencing was validated by artificial microRNA experiments in a transient expression system and by RNA ligase-mediated rapid amplification of cDNA ends. Viroid mutants incapable of targeting callose synthase mRNAs failed to induce typical infection phenotypes, whereas a chimeric viroid obtained by swapping the virulence modulating regions of a mild and a severe variant of Potato spindle tuber viroid greatly affected the accumulation of viroids and the severity of disease symptoms. These data provide evidence of the silencing of multiple genes by a single small RNA derived from a viroid.
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Affiliation(s)
- Charith Raj Adkar-Purushothama
- RNA Group/Groupe ARN, Département de Biochimie, Faculté de Médecine des Sciences de la Santé, Pavillon de Recherche Appliquée au Cancer, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada
| | - Chantal Brosseau
- Centre SÈVE, Département de Biologie, Université de Sherbrooke, Quebec J1K 2R1, Canada
| | - Tamara Giguère
- RNA Group/Groupe ARN, Département de Biochimie, Faculté de Médecine des Sciences de la Santé, Pavillon de Recherche Appliquée au Cancer, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada
| | - Teruo Sano
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki 036-8561, Japan
| | - Peter Moffett
- Centre SÈVE, Département de Biologie, Université de Sherbrooke, Quebec J1K 2R1, Canada
| | - Jean-Pierre Perreault
- RNA Group/Groupe ARN, Département de Biochimie, Faculté de Médecine des Sciences de la Santé, Pavillon de Recherche Appliquée au Cancer, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada
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Viroids, the simplest RNA replicons: How they manipulate their hosts for being propagated and how their hosts react for containing the infection. Virus Res 2015; 209:136-45. [PMID: 25738582 DOI: 10.1016/j.virusres.2015.02.027] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/23/2015] [Accepted: 02/23/2015] [Indexed: 12/31/2022]
Abstract
The discovery of viroids about 45 years ago heralded a revolution in Biology: small RNAs comprising around 350 nt were found to be able to replicate autonomously-and to incite diseases in certain plants-without encoding proteins, fundamental properties discriminating these infectious agents from viruses. The initial focus on the pathological effects usually accompanying infection by viroids soon shifted to their molecular features-they are circular molecules that fold upon themselves adopting compact secondary conformations-and then to how they manipulate their hosts to be propagated. Replication of viroids-in the nucleus or chloroplasts through a rolling-circle mechanism involving polymerization, cleavage and circularization of RNA strands-dealt three surprises: (i) certain RNA polymerases are redirected to accept RNA instead of their DNA templates, (ii) cleavage in chloroplastic viroids is not mediated by host enzymes but by hammerhead ribozymes, and (iii) circularization in nuclear viroids is catalyzed by a DNA ligase redirected to act upon RNA substrates. These enzymes (and ribozymes) are most probably assisted by host proteins, including transcription factors and RNA chaperones. Movement of viroids, first intracellularly and then to adjacent cells and distal plant parts, has turned out to be a tightly regulated process in which specific RNA structural motifs play a crucial role. More recently, the advent of RNA silencing has brought new views on how viroids may cause disease and on how their hosts react to contain the infection; additionally, viroid infection may be restricted by other mechanisms. Representing the lowest step on the biological size scale, viroids have also attracted considerable interest to get a tentative picture of the essential characteristics of the primitive replicons that populated the postulated RNA world.
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Minoia S, Navarro B, Delgado S, Di Serio F, Flores R. Viroid RNA turnover: characterization of the subgenomic RNAs of potato spindle tuber viroid accumulating in infected tissues provides insights into decay pathways operating in vivo. Nucleic Acids Res 2015; 43:2313-25. [PMID: 25662219 PMCID: PMC4344493 DOI: 10.1093/nar/gkv034] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
While biogenesis of viroid RNAs is well-known, how they decay is restricted to data involving host RNA silencing. Here we report an alternative degradation pathway operating on potato spindle tuber viroid (PSTVd), the type species of nuclear-replicating viroids (family Pospiviroidae). Northern-blot hybridizations with full- and partial-length probes revealed a set of PSTVd (+) subgenomic (sg)RNAs in early-infected eggplant, some partially overlapping and reaching levels comparable to those of the genomic circular and linear forms. Part of the PSTVd (+) sgRNAs were also observed in Nicotiana benthamiana (specifically in the nuclei) and tomato, wherein they have been overlooked due to their low accumulation. Primer extensions of representative (+) sgRNAs failed to detect a common 5′ terminus, excluding that they could result from aborted transcription initiated at one specific site. Supporting this view, 5′- and 3′-RACE indicated that the (+) sgRNAs have 5′-OH and 3′-P termini most likely generated by RNase-mediated endonucleolytic cleavage of longer precursors. These approaches also unveiled PSTVd (−) sgRNAs with features similar to their (+) counterparts. Our results provide a mechanistic insight on how viroid decay may proceed in vivo during replication, and suggest that synthesis and decay of PSTVd strands might be coupled as in mRNA.
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Affiliation(s)
- Sofia Minoia
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Beatriz Navarro
- Istituto per la Protezione Sostenibile delle Piante, UOS Bari, Consiglio Nazionale delle Ricerche, Bari, Italy
| | - Sonia Delgado
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Francesco Di Serio
- Istituto per la Protezione Sostenibile delle Piante, UOS Bari, Consiglio Nazionale delle Ricerche, Bari, Italy
| | - Ricardo Flores
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain
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Kovalskaya N, Hammond RW. Molecular biology of viroid-host interactions and disease control strategies. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 228:48-60. [PMID: 25438785 DOI: 10.1016/j.plantsci.2014.05.006] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/26/2014] [Accepted: 05/14/2014] [Indexed: 06/04/2023]
Abstract
Viroids are single-stranded, covalently closed, circular, highly structured noncoding RNAs that cause disease in several economically important crop plants. They replicate autonomously and move systemically in host plants with the aid of the host machinery. In addition to symptomatic infections, viroids also cause latent infections where there is no visual evidence of infection in the host; however, transfer to a susceptible host can result in devastating disease. While there are non-hosts for viroids, no naturally occurring durable resistance has been observed in most host species. Current effective control methods for viroid diseases include detection and eradication, and cultural controls. In addition, heat or cold therapy combined with meristem tip culture has been shown to be effective for elimination of viroids for some viroid-host combinations. An understanding of viroid-host interactions, host susceptibility, and non-host resistance could provide guidance for the design of viroid-resistant plants. Efforts to engineer viroid resistance into host species have been underway for several years, and include the use of antisense RNA, antisense RNA plus ribozymes, a dsRNase, and siRNAs, among others. The results of those efforts and the challenges associated with creating viroid resistant plants are summarized in this review.
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Affiliation(s)
- Natalia Kovalskaya
- USDA ARS BARC Molecular Plant Pathology Laboratory, Beltsville, MD 20705, USA
| | - Rosemarie W Hammond
- USDA ARS BARC Molecular Plant Pathology Laboratory, Beltsville, MD 20705, USA.
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Koval' T, Lipovová P, Podzimek T, Matoušek J, Dušková J, Skálová T, Stěpánková A, Hašek J, Dohnálek J. Plant multifunctional nuclease TBN1 with unexpected phospholipase activity: structural study and reaction-mechanism analysis. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:213-26. [PMID: 23385457 DOI: 10.1107/s0907444912043697] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 10/22/2012] [Indexed: 11/11/2022]
Abstract
Type I plant nucleases play an important role in apoptotic processes and cell senescence. Recently, they have also been indicated to be potent anticancer agents in in vivo studies. The first structure of tomato nuclease I (TBN1) has been determined, its oligomerization and activity profiles have been analyzed and its unexpected activity towards phospholipids has been discovered, and conclusions are drawn regarding its catalytic mechanism. The structure-solution process required X-ray diffraction data from two crystal forms. The first form was used for phase determination; the second form was used for model building and refinement. TBN1 is mainly α-helical and is stabilized by four disulfide bridges. Three observed oligosaccharides are crucial for its stability and solubility. The active site is localized at the bottom of the positively charged groove and contains a zinc cluster that is essential for enzymatic activity. An equilibrium between monomers, dimers and higher oligomers of TBN1 was observed in solution. Principles of the reaction mechanism of the phosphodiesterase activity are suggested, with central roles for the zinc cluster, the nucleobase-binding pocket (Phe-site) and Asp70, Arg73 and Asn167. Based on the distribution of surface residues, possible binding sites for dsDNA and other nucleic acids with secondary structure were identified. The phospholipase activity of TBN1, which is reported for the first time for a nuclease, significantly broadens the substrate promiscuity of the enzyme, and the resulting release of diacylglycerol, which is an important second messenger, can be related to the role of TBN1 in apoptosis.
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Affiliation(s)
- Tomáš Koval'
- Institute of Macromolecular Chemistry, AS CR, v.v.i., Heyrovskeho nam. 2, 162 06 Praha 6, Czech Republic.
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Podzimek T, Matoušek J, Lipovová P, Poučková P, Spiwok V, Santrůček J. Biochemical properties of three plant nucleases with anticancer potential. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2011; 180:343-51. [PMID: 21421379 DOI: 10.1016/j.plantsci.2010.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 09/15/2010] [Accepted: 10/08/2010] [Indexed: 05/30/2023]
Abstract
Biochemical and structural properties of three recombinant (R), highly homologous, plant bifunctional nucleases from tomato (R-TBN1), hop (R-HBN1) and Arabis brassica (R-ABN1) were determined. These nucleases cleave single- and double-stranded substrates, as well as both RNA and DNA with nearly the same efficiency. In addition, they are able to cleave several artificial substrates and highly stable viroid RNA. They also possess 3'-nucleotidase activity; therefore, they can be classified as nuclease I family members. Interestingly, poly(G) is resistant to cleavage and moreover it inhibits dsDNase, ssDNase and RNase activity of the studied nucleases. All three nucleases exhibit zinc-dependence and a strong stimulatory effect of Zn²+ for dsDNA cleavage. 3-D models, predicted on the basis of experimental structure of P1 nuclease, show nine amino acid residues responsible for interactions with zinc atoms, located in the same positions as in P1 nuclease. It was also shown that R-TBN1, R-HBN1, and R-ABN1 are all N-glycosylated. Oligosaccharidic chains constitute about 16% of their MW. In addition, an anticancer potential of the R-ABN1 is compared in this work with previously tested R-TBN1, and R-HBN1. R-ABN1 injected intravenously showed 70% inhibitory effect on growth of human prostate carcinoma in athymic mice.
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Affiliation(s)
- Tomáš Podzimek
- Institute of Chemical Technology Prague, Technická 3, 166 28 Prague, Czech Republic; Biology Centre, ASCR v.v.i., Institute of Plant Molecular Biology, Branišovská 32, 37005 České Budějovice, Czech Republic.
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Koval' T, Lipovová P, Podzimek T, Matoušek J, Dušková J, Skálová T, Stěpánková A, Hašek J, Dohnálek J. Crystallization of recombinant bifunctional nuclease TBN1 from tomato. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:124-8. [PMID: 21206042 PMCID: PMC3079990 DOI: 10.1107/s1744309110048177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 11/18/2010] [Indexed: 11/10/2022]
Abstract
The endonuclease TBN1 from Solanum lycopersicum (tomato) was expressed in Nicotiana benthamiana leaves and purified with suitable quality and in suitable quantities for crystallization experiments. Two crystal forms (orthorhombic and rhombohedral) were obtained and X-ray diffraction experiments were performed. The presence of natively bound Zn2+ ions was confirmed by X-ray fluorescence and by an absorption-edge scan. X-ray diffraction data were collected from the orthorhombic (resolution of 5.2 Å) and rhombohedral (best resolution of 3.2 Å) crystal forms. SAD, MAD and MR methods were applied for solution of the phase problem, with partial success. TBN1 contains three Zn2+ ions in a similar spatial arrangement to that observed in nuclease P1 from Penicillium citrinum.
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Affiliation(s)
- Tomáš Koval'
- Institute of Physics AS CR, v.v.i., Na Slovance 2, 182 21 Praha 8, Czech Republic.
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Abstract
Viroids are single-stranded, circular, and noncoding RNAs that infect plants. They replicate in the nucleus or chloroplast and then traffic cell-to-cell through plasmodesmata and long distance through the phloem to establish systemic infection. They also cause diseases in certain hosts. All functions are mediated directly by the viroid RNA genome or genome-derived RNAs. I summarize recent advances in the understanding of viroid structures and cellular factors enabling these functions, emphasizing conceptual developments, major knowledge gaps, and future directions. Newly emerging experimental systems and research tools are discussed that are expected to enable significant progress in a number of key areas. I highlight examples of groundbreaking contributions of viroid research to the development of new biological principles and offer perspectives on using viroid models to continue advancing some frontiers of life science.
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Affiliation(s)
- Biao Ding
- Department of Plant Cellular and Molecular Biology and Plant Biotechnology Center, The Ohio State University, Columbus, Ohio 43210, USA.
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