Dag-Ragnar Blystad
Research Professor
Authors
Jana Fránová Jaroslava Pribylová Rostislav Zemek Jiunn Luh Tan Zhibo Hamborg Dag-Ragnar Blystad Ondrej Lenz Igor KoloniukAbstract
No abstract has been registered
Authors
Jana Fránová Jaroslava Pribylová Rostislav Zemek Jiunn Luh Tan Zhibo Hamborg Dag-Ragnar Blystad Ondrej Lenz Igor KoloniukAbstract
No abstract has been registered
Authors
Igor Koloniuk Jana Fránová Jaroslava Pribylová Tatiana Sarkisova Josef Špak Jiunn Luh Tan Rostislav Zemek Radek Cmejla Martina Rejlová Lucie Valentová Jiri Sedlák Jan Holub Jan Skalik Dag-Ragnar Blystad Bijaya Sapkota Zhibo HamborgAbstract
Raspberry plants, valued for their fruits, are vulnerable to a range of viruses that adversely affect their yield and quality. Utilizing high-throughput sequencing (HTS), we identified a novel virus, tentatively named raspberry enamovirus 1 (RaEV1), in three distinct raspberry plants. This study provides a comprehensive characterization of RaEV1, focusing on its genomic structure, phylogeny, and possible transmission routes. Analysis of nearly complete genomes from 14 RaEV1 isolates highlighted regions of variance, particularly marked by indel events. The evidence from phylogenetic and sequence analyses supports the classification of RaEV1 as a distinct species within the Enamovirus genus. Among the 289 plant and 168 invertebrate samples analyzed, RaEV1 was detected in 10.4% and 0.4%, respectively. Most detections occurred in plants that were also infected with other common raspberry viruses. The virus was present in both commercial and wild raspberries, indicating the potential of wild plants to act as viral reservoirs. Experiments involving aphids as potential vectors demonstrated their ability to acquire RaEV1 but not to successfully transmit it to plants.
Authors
Bjørn Arild Hatteland May Bente Brurberg Rosemarie Tedeschi Wolfgang Jarausch Barbara Jarausch Dag-Ragnar BlystadAbstract
No abstract has been registered
Abstract
The estimated global production of raspberry from year 2016 to 2020 averaged 846,515 tons. The most common cultivated Rubus spp. is European red raspberry (Rubus idaeus L. subsp. idaeus). Often cultivated for its high nutritional value, the red raspberry (Rubus idaeus) is susceptible to multiple viruses that lead to yield loss. These viruses are transmitted through different mechanisms, of which one is invertebrate vectors. Aphids and nematodes are known to be vectors of specific raspberry viruses. However, there are still other potential raspberry virus vectors that are not well-studied. This review aimed to provide an overview of studies related to this topic. All the known invertebrates feeding on raspberry were summarized. Eight species of aphids and seven species of plant-parasitic nematodes were the only proven raspberry virus vectors. In addition, the eriophyid mite, Phyllocoptes gracilis, has been suggested as the natural vector of raspberry leaf blotch virus based on the current available evidence. Interactions between vector and non-vector herbivore may promote the spread of raspberry viruses. As a conclusion, there are still multiple aspects of this topic that require further studies to get a better understanding of the interactions among the viral pathogens, invertebrate vectors, and non-vectors in the raspberry agroecosystem. Eventually, this will assist in development of better pest management strategies.
Authors
Jiunn Luh Tan Nina Trandem Rostislav Zemek Zhibo Hamborg Bijaya Sapotka Dag-Ragnar Blystad Jana FránováAbstract
No abstract has been registered
Authors
Jens H. Kuhn Scott Adkins Bernard R. Agwanda Rim Al Kubrusli Sergey V. Alkhovsky Gaya K. Amarasinghe Tatjana Avšič-Županc María A. Ayllón Justin Bahl Anne Balkema-Buschmann Matthew J. Ballinger Christopher F. Basler Sina Bavari Martin Beer Nicolas Bejerman Andrew J. Bennett Dennis A. Bente Éric Bergeron Brian H. Bird Carol D. Blair Kim R. Blasdell Dag-Ragnar Blystad Jamie Bojko Wayne B. Borth Steven Bradfute Rachel Breyta Thomas Briese Paul A. Brown Judith K. Brown Ursula J. Buchholz Michael J. Buchmeier Alexander Bukreyev Felicity Burt Carmen Büttner Charles H. Calisher Mengji Cao Inmaculada Casas Kartik Chandran Rémi N. Charrel Qi Cheng Yuya Chiaki Marco Chiapello Il-Ryong Choi Marina Ciuffo J. Christopher S. Clegg Ian Crozier Elena Dal Bó Juan Carlos de la Torre Xavier de Lamballerie Rik L. de Swart Humberto Debat Nolwenn M. Dheilly Emiliano Di Cicco Nicholas Di Paola Francesco Di Serio Ralf G. Dietzgen Michele Digiaro Olga Dolnik Michael A. Drebot J. Felix Drexler William G. Dundon W. paul Duprex Ralf Dürrwald John M. Dye Andrew J. Easton Hideki Ebihara Toufic Elbeaino Koray Ergünay Hugh W. Ferguson Anthony R. Fooks Marco Forgia Pierre B.H. Formenty Jana Fránová Juliana Freitas-Astúa Jingjing Fu Stephanie Fürl Selma Gago-Zachert George Fú Gāo María Laura García Adolfo García-Sastre Aura R. Garrison Thomas Gaskin Jean-Paul J. Gonzalez Anthony Griffiths Tony L. Goldberg Martin H. Groschup Stephan Günther Roy A. Hall John Hammond Tong Han Jussi Hepojoki Roger Hewson Jiang Hong Ni Hong Seiji Hongo Masayuki Horie John S. Hu Tao Hu Holly R. Hughes Florian Hüttner Timothy H. Hyndman M. Ilyas Risto Jalkanen Dàohóng Jiāng Gilda B. Jonson Sandra Junglen Fujio Kadono Karia H. Kaukinen Michael Kawate Boris Klempa Jonas Klingström Gary Kobinger Igor Koloniuk Hideki Kondo Eugene V. Koonin Mart Krupovic Kenji Kubota Gael Kurath Lies Laenen Amy J. Lambert Stanley L. Langevin Benhur Lee Elliot J. Lefkowitz Eric M. Leroy Shaorong Li Longhui Li Jianrong Li Huazhen Liu Igor S. Lukashevich Piet Maes William Marciel de Souza Marco Marklewitz Sergio H. Marshall Shin-Yi L. Marzano Sebastien Massart John W. McCauley Michael Melzer Nicole Mielke-Ehret Kristina M. Miller Tobi J. Ming Ali Mirazimi Gideon J. Mordecai Hans-Peter Mühlbach Elke Mühlberger Rayapati Naidu Tomohide Natsuaki José A. Navarro Sergey V. Netesov Gabriele Neumann Norbert Nowotny Márcio R. T. Nunes Alejandro Olmedo-Velarde Gustavo Palacios Vicente Pallás Bernadett Pályi Anna Papa Sofia Paraskevopoulou Adam C. Park Colin R. Parrish David A. Patterson Alex Pauvolid-Corrêa Janusz T. Pawęska Susan Payne Carlotta Peracchio Daniel R. Pérez Thomas S. Postler Liying Qi Sheli R. Radoshitzky Renato O. Resende Carina A. Reyes Bertus K. Rima Gabriel Robles Luna Víctor Romanowski Paul Rota Dennis Rubbenstroth Luisa Rubino Jonathan Runstadler Sead Sabanadzovic Amadou Alpha Sall Maria S. Salvato Rosemary Sang Takahide Sasaya Angela D. Schulze Martin Schwemmle Mang Shi Xiǎohóng Shí Zhènglì Shí Yoshifumi Shimomoto Yukio Shirako Stuart G. Siddell Peter Simmonds Manuela Sironi Guy Smagghe Sophie J. Smither Jin-Won Song Kirsten Spann Jessica R. Spengler Mark D. Stenglein David M. Stone Jari Sugano Curtis A. Suttle Amy Tabata Ayato Takada Shigeharu Takeuchi David P. Tchouassi Amy Teffer Robert B. Tesh Natalie J. Thornburg Yasuhiro Tomitaka Keizō Tomonaga Noël Tordo Baldwyn Torto Jonathan S. Towner Shinya Tsuda Changchun Tu Massimo Turina Ioannis E. Tzanetakis Janice Uchida Tomio Usugi Anna Maria Vaira Marta Vallino Bernadette van den Hoogen Arvind Varsani Nikos Vasilakis Martin Verbeek Susanne von Bargen Jiro Wada Victoria Wahl Peter J. Walker Lin-Fa Wang Guoping Wang Yanxiang Wang Yaqin Wang Muhammad Waqas Tàiyún Wèi Shaohua Wen Anna E. Whitfield John V. Williams Yuri I. Wolf Jiangxiang Wu Lei Xu Hironobu Yanagisawa Caixia Yang Zuokun Yang F. Murilo Zerbini Lifeng Zhai Yong-Zhen Zhang Song Zhang Jinguo Zhang Zhe Zhang Xueping ZhouAbstract
In March 2021, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by four families (Aliusviridae, Crepuscuviridae, Myriaviridae, and Natareviridae), three subfamilies (Alpharhabdovirinae, Betarhabdovirinae, and Gammarhabdovirinae), 42 genera, and 200 species. Thirty-nine species were renamed and/or moved and seven species were abolished. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.
Authors
Jens H. Kuhn Scott Adkins Bernard R. Agwanda Rim Al Kubrusli Sergey V. Alkhovsky Gaya K. Amarasinghe Tatjana Avšič-Županc María A. Ayllón Justin Bahl Anne Balkema-Buschmann Matthew J. Ballinger Christopher F. Basler Sina Bavari Martin Beer Nicolas Bejerman Andrew J. Bennett Dennis A. Bente Éric Bergeron Brian H. Bird Carol D. Blair Kim R. Blasdell Dag-Ragnar Blystad Jamie Bojko Wayne B. Borth Steven Bradfute Rachel Breyta Thomas Briese Paul A. Brown Judith K. Brown Ursula J. Buchholz Michael J. Buchmeier Alexander Bukreyev Felicity Burt Carmen Büttner Charles H. Calisher Mengji Cao Inmaculada Casas Kartik Chandran Rémi N. Charrel Qi Cheng Yuya Chiaki Marco Chiapello Il-Ryong Choi Marina Ciuffo J. Christopher S. Clegg Ian Crozier Elena Dal Bó Juan Carlos de la Torre Xavier de Lamballerie Rik L. de Swart Humberto Debat Nolwenn M. Dheilly Emiliano Di Cicco Nicholas Di Paola Francesco Di Serio Ralf G. Dietzgen Michele Digiaro Olga Dolnik Michael A. Drebot J. Felix Drexler William G. Dundon W. Paul Duprex Ralf Dürrwald John M. Dye Andrew J. Easton Hideki Ebihara Toufic Elbeaino Koray Ergünay Hugh W. Ferguson Anthony R. Fooks Marco Forgia Pierre B. H. Formenty Jana Fránová Juliana Freitas-Astúa Jingjing Fu Stephanie Fürl Selma Gago-Zachert George Fú Gāo María Laura García Adolfo García-Sastre Aura R. Garrison Thomas Gaskin Jean-Paul J. Gonzalez Anthony Griffiths Tony L. Goldberg Martin H. Groschup Stephan Günther Roy A. Hall John Hammond Tong Han Jussi Hepojoki Roger Hewson Jiang Hong Ni Hong Seiji Hongo Masayuki Horie John S. Hu Tao Hu Holly R. Hughes Florian Hüttner Timothy H. Hyndman M. Ilyas Risto Jalkanen Dàohóng Jiāng Gilda B. Jonson Sandra Junglen Fujio Kadono Karia H. Kaukinen Michael Kawate Boris Klempa Jonas Klingström Gary Kobinger Igor Koloniuk Hideki Kondō Eugene V. Koonin Mart Krupovic Kenji Kubota Gael Kurath Lies Laenen Amy J. Lambert Stanley L. Langevin Benhur Lee Elliot J. Lefkowitz Eric M. Leroy Shaorong Li Longhui Li Jiànróng Lǐ Huazhen Liu Igor S. Lukashevich Piet Maes William Marciel de Souza Marco Marklewitz Sergio H. Marshall Shin-Yi L. Marzano Sebastien Massart John W. McCauley Michael Melzer Nicole Mielke-Ehret Kristina M. Miller Tobi J. Ming Ali Mirazimi Gideon J. Mordecai Hans-Peter Mühlbach Elke Mühlberger Rayapati Naidu Tomohide Natsuaki José A. Navarro Sergey V. Netesov Gabriele Neumann Norbert Nowotny Márcio R. T. Nunes Alejandro Olmedo-Velarde Gustavo Palacios Vicente Pallás Bernadett Pályi Anna Papa Sofia Paraskevopoulou Adam C. Park Colin R. Parrish David A. Patterson Alex Pauvolid-Corrêa Janusz T. Pawęska Susan Payne Carlotta Peracchio Daniel R. Pérez Thomas S. Postler Liying Qi Sheli R. Radoshitzky Renato O. Resende Carina A. Reyes Bertus K. Rima Gabriel Robles Luna Víctor Romanowski Paul Rota Dennis Rubbenstroth Luisa Rubino Jonathan A. Runstadler Sead Sabanadzovic Amadou Alpha Sall Maria S. Salvato Rosemary Sang Takahide Sasaya Angela D. Schulze Martin Schwemmle Mang Shi Xiǎohóng Shí Zhènglì Shí Yoshifumi Shimomoto Yukio Shirako Stuart G. Siddell Peter Simmonds Manuela Sironi Guy Smagghe Sophie Smither Jin-Won Song Kirsten Spann Jessica R. Spengler Mark D. Stenglein David M. Stone Jari Sugano Curtis A. Suttle Amy Tabata Ayato Takada Shigeharu Takeuchi David P. Tchouassi Amy Teffer Robert B. Tesh Natalie J. Thornburg Yasuhiro Tomitaka Keizō Tomonaga Noël Tordo Baldwyn Torto Jonathan S. Towner Shinya Tsuda Changchun Tu Massimo Turina Ioannis E. Tzanetakis Janice Uchida Tomio Usugi Anna Maria Vaira Marta Vallino Bernadette van den Hoogen Arvind Varsani Nikos Vasilakis Martin Verbeek Susanne von Bargen Jiro Wada Victoria Wahl Peter J. Walker Lin-Fa Wang Guoping Wang Yanxiang Wang Yaqin Wang Muhammad Waqas Tàiyún Wèi Shaohua Wen Anna E. Whitfield John V. Williams Yuri I. Wolf Jiangxiang Wu Lei Xu Hironobu Yanagisawa Caixia Yang Zuokun Yang F. Murilo Zerbini Lifeng Zhai Yong-Zhen Zhang Song Zhang Jinguo Zhang Zhe Zhang Xueping ZhouAbstract
No abstract has been registered
Abstract
Plant virus eradication is a prerequisite for the use of virus-free propagules for sustainable crop production. In contrast, virus preservation is required for all types of applied and basic research of viruses. Shoot tip cryopreservation can act as a double-edged strategy, facilitating either virus eradication or virus preservation in cryoderived plants. Here, we tested the efficacies of shoot tip cryopreservation for virus eradication and preservation in shallot (Allium cepa var. aggregatum). In vitro stock shallot shoots infected with onion yellow dwarf virus (OYDV) and shallot latent virus were thermotreated for 0, 2, and 4 weeks at a constant temperature of 36℃ before shoot tip cryopreservation. Results showed that viruses were preserved in recovered shoots when thermotherapy was not applied. Although thermotherapy lowered the regrowth levels of cryotreated shoot tips, the efficiency of virus eradication increased from 5% to 54%. Immunolocalization of OYDV and histological observation of cryotreated shoot tips showed the high frequency of virus preservation was due to the viral invasion of cells close to the apical meristem and the high proportion of cells surviving. Four weeks of thermotherapy drastically decreased the distribution of OYDV, as well as the percentage of surviving cells within the shoot tips, thereby promoting virus eradication. Virus-free plants obtained from combining thermotherapy with cryotherapy showed significantly improved vegetative growth and bulb production. The present study reports how thermotherapy can act as a trigger to facilitate either the safe preservation of Allium viruses or the production of virus-free shallot plants.
Authors
Min-Rui Wang Wenlu Bi Mukund R. Shukla Li Ren Zhibo Hamborg Dag-Ragnar Blystad Praveen K. Saxena Qiao-Chun WangAbstract
Cryopreservation is considered an ideal strategy for the long-term preservation of plant genetic resources. Significant progress was achieved over the past several decades, resulting in the successful cryopreservation of the genetic resources of diverse plant species. Cryopreservation procedures often employ in vitro culture techniques and require the precise control of several steps, such as the excision of explants, preculture, osmo- and cryoprotection, dehydration, freeze-thaw cycle, unloading, and post-culture for the recovery of plants. These processes create a stressful environment and cause reactive oxygen species (ROS)-induced oxidative stress, which is detrimental to the growth and regeneration of tissues and plants from cryopreserved tissues. ROS-induced oxidative stresses were documented to induce (epi)genetic and somatic variations. Therefore, the development of true-to-type regenerants of the source germplasm is of primary concern in the application of plant cryopreservation technology. The present article provides a comprehensive assessment of epigenetic and genetic integrity, metabolic stability, and field performance of cryopreserved plants developed in the past decade. Potential areas and the directions of future research in plant cryopreservation are also proposed.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Min-Rui Wang Zhibo Hamborg Rune Slimestad Abdelhameed Elameen Dag-Ragnar Blystad Sissel Haugslien Gry Skjeseth Qiao‑Chun WangAbstract
Shallot (Allium cepa var. aggregatum), a small bulb onion, is widely grown in the world. We previously reported a droplet-vitrification for cryopreservation of in vitro-grown shoot tips of shallot genotype ‘10603’. The present study further evaluated rooting, vegetative growth, bulb production and contents of biochemical compounds, as well as genetic stability in cryo-derived plants. The results showed no significant differences in rooting, vegetative growth, bulb production and contents of soluble sugars and flavonols between the cryo- and in vitro-derived plants. Analyses of ISSR and AFLP markers did not detect any polymorphic bands in the cryo-derived plants. These results indicate rooting and vegetative growth ability, biochemical compounds and genetic stability were maintained in cryo-derived plants. The present study provides experimental evidences that support the use of cryopreservation method for long-term preservation of genetic resources of shallots and other Allium species.
Authors
Susanne von Bargen Rim Al Kubrusli Thomas Gaskin Stephanie Fürl Florian Hüttner Dag-Ragnar Blystad David G. Karlin Risto Jalkanen Carmen BüttnerAbstract
Since Emaraviruses have been discovered in 2007 several new species were detected in a range of host plants. Five genome segments of a novel Emaravirus from mosaic‐diseased Eurasian aspen (Populus tremula) have been completely determined. The monocistronic, segmented ssRNA genome of the virus shows a genome organisation typical for Emaraviruses encoding the viral RNA‐dependent RNA polymerase (RdRP, 268.2 kDa) on RNA1 (7.1 kb), a glycoprotein precursor (GPP, 73.5 kDa) on RNA2 (2.3 kb), the viral nucleocapsid protein (N, 35.6 kDa) on RNA3 (1.6 kb), and a putative movement protein (MP, 41.0 kDa) on RNA4 (1.6 kb). The fifth identified genome segment (RNA5, 1.3 kb) encodes a protein of unknown function (P28, 28.1 kDa). We discovered that it is distantly related to proteins encoded by Emaraviruses, such as P4 of European mountain ash ringspot‐associated virus. All proteins from this group contain a central hydrophobic region with a conserved secondary structure and a hydrophobic amino acid stretch, bordered by two highly conserved positions, thus clearly representing a new group of homologues of Emaraviruses. The virus identified in Eurasian aspen is closely associated with observed leaf symptoms, such as mottle, yellow blotching, variegation and chloroses along veins. All five viral RNAs were regularly detectable by RT‐PCR in mosaic‐diseased P. tremula in Norway, Finland and Sweden (Fennoscandia). Observed symptoms and testing of mosaic‐diseased Eurasian aspen by virus‐specific RT‐PCR targeting RNA3 and RNA4 confirmed a wide geographic distribution of the virus in Fennoscandia. We could demonstrate that the mosaic‐disease is graft‐transmissible and confirmed that the virus is the causal agent by detection in symptomatic, graft‐inoculated seedlings used as rootstocks as well as in the virus‐infected scions used for graft‐inoculation. Owing to these characteristics, the virus represents a novel species within the genus Emaravirus and was tentatively denominated aspen mosaic‐associated virus.
Abstract
The present study described a combining thermotherapy with meristem culture for improved eradication of onion yellow dwarf virus (OYDV) and shallot latent virus (SLV) from co‐infected in vitro‐cultured shallot shoots. In vitro‐cultured shoots infected with OYDV and SLV were thermo‐treated at a constant temperature of 36°C for 0, 2 and 4 weeks, and then meristems (0.5 mm) containing 1–2 leaf primordia were excised and cultured for shoot regrowth. Meristem culture without thermotherapy produced much higher levels of survival (100%) and shoot regrowth (55%) than those (62% survival and 32% shoot regrowth) produced by the procedure combining 4 weeks of thermotherapy with meristem culture. However, much higher virus‐free frequencies (70% for OYSV, 80% for SLV and 50% for both viruses) were obtained in the latter than those (10% for OYSV, 15% for SLV and 10% for both viruses) obtained in the former. Histological and subcellular studies showed that thermotherapy imposed stress or damage to the cells of meristems, thus resulting in reduced meristem survival and shoot regrowth. Studies on virus location revealed considerable alternations of virus distribution patterns in the thermo‐treated meristems. The results of histological and subcellular studies and analysis of virus distribution pattern added valuable experimental data in the combining thermotherapy with meristem culture for virus eradication. These data provided explanations as to why combining thermotherapy with meristem culture improved the eradication of OYDV and SLV from the virus‐infected in vitro shallot shoots.
Authors
Min-Rui Wang Zhibo Hamborg Sissel Haugslien Astrid Sivertsen Morten Rasmussen Qiaochun Wang Dag-Ragnar BlystadAbstract
Shallot (Allium cepa var. aggregatum) is an important vegetable crop belonging to the genus Allium. The present study attempted to develop an efficient droplet-vitrification cryopreservation method for shallot ‘10603’ shoot tips. In vitro stock shoots were maintained on Murashige and Skoog (1962) medium (MS) supplemented with 30 g L-1 sucrose, 0.5 mg L-1 BAP, 0.1 mg L-1 NAA and 8 g L-1 agar (pH=5.8). Shoot tips (2.0-3.0 mm in length) were excised from 4-week-old stock shoots and stepwise precultured with increased sucrose concentrations from 0.3 to 0.5 M, each concentration for 1 day. The precultured shoot tips were then loaded for 20 min with a solution composed of 2 M glycerol and 0.5 M sucrose, before exposure to PVS3 for 3 h at room temperature. Dehydrated shoot tips were transferred onto aluminum foils (2×0.8 cm), prior to direct immersion into liquid nitrogen (LN) for cryostorage. For thawing, frozen aluminum foils were moved from LN and immediately transferred into unloading solution composed of liquid MS containing 1.2 M sucrose. After incubation at room temperature for 20 min, shoot tips were post-cultured on solidified MS medium containing 0.3 M sucrose for 2 days and then transferred onto a recovery medium for shoot regrowth. With this procedure, 94% shoot tips survived, and 58% shoot tips regenerated into shoots following cryopreservation.
Authors
Min-Rui Wang Zhibo Hamborg Jiří Zámečník Alois Bilavčík Dag-Ragnar Blystad Sissel Haugslien Qiao-Chun WangAbstract
The present study described a droplet-vitrification cryopreservation for shoot tips of shallot (Allium cepa var. aggregatum), a small bulb onion. Shoot tips taken from in vitro stock shoots were precultured with 0.3 M and 0.5 M of sucrose, with 1 day for each concentration. Precultured shoot tips were treated with a loading solution containing 2 M glycerol and 0.6 M sucrose for 20 min and then exposed to plant vitrification solution 3 (PVS3) at 24 °C for 3 h of dehydration. Following exposure to PVS3, shoot tips were moved onto 5.0 μl PVS3 droplets on aluminum foil strips, followed by direct immersion into liquid nitrogen for 1 h. Frozen shoot tips were thawed by incubation in liquid MS medium containing 1.2 m sucrose for 20 min at room temperature, and then post-thaw cultured for shoot regrowth. Exposure of the shoot tips to PVS3 produced shoot regrowth (58%). Differential scanning calorimetry (DSC) detected 1.8% of freezable water in the shoot tips that had been dehydrated by PVS2, and no freezable water in those by PVS3 treatment. Exposure to PVS3 provided a broader safe temperature range (− 196 °C to − 88 °C), compared to that (− 196 °C to − 116 °C) of PVS2, for cryopreserved samples. Histological observations found that PVS3 dehydration allowed many cells in the apical dome and in the leaf primordia to survive following freezing in LN, while PVS2 dehydration resulted in much fewer surviving cells in the apical dome. The droplet-vitrification cryopreservation produced 56%, 72% and 32% shoot regrowth in cryopreserved shoot tips taken from in vitro shoots, adventitious buds regenerated from stem discs and field-grown bulbs, respectively. Advantages and disadvantages of the use of different source explants for cryopreservation were discussed. The droplet-vitrification cryopreservation produced 45% and 70% shoot regrowth in the additional two shallot genotypes ‘Kverve’ and ‘Lunteviga’. The results obtained in this study provide technical supports for setting-up cryo-bankings of genetic resources of shallots and other Allium species.
Abstract
Potato (Solanum tuberosum L.) is one of the most important crops grown in Norway, and virus-free plants are required for commercial potato production and for preservation of potato germplasm. The present study evaluates three in vitro therapies – meristem culture, cryotherapy, and chemotherapy combined with thermotherapy – to eliminate viruses from eight historically valuable potato cultivars belonging to the Norwegian potato germplasm. Potato virus Y, potato virus M, potato virus X and potato virus S were present in eight selected old potato cultivars due to long-term conservation in open field. Double-antibody sandwich enzyme-linked immunological assay (DAS-ELISA) and biological indicators were the standard tests used to confirm virus infection in our study. Six virus-free plants from four potato cultivars were obtained after meristem culture, and no virus-free potato cultivars were obtained after cryotherapy. Virus-free frequency for eight different potato cultivars after combining chemotherapy with thermotherapy varied from 36.4% to 100%, with single virus elimination rates of between 74.2% and 92.9%. Chemotherapy compared with thermotherapy was the most effective of the three in vitro therapies used in this study. Highly sensitive small RNA high-throughput sequencing (HTS) was used to evaluate the virus status of potato virus-free materials after virus eradication, and no virus was found, which was consistent with the results of DAS-ELISA and biological indicators. Small RNA HTS has been reported for the first time to evaluate the virus status after virus elimination and to control virus-free potato nuclear stocks.
Abstract
No abstract has been registered
Authors
Merike Sõmera Anders Kvarnheden Cécile Desbiez Dag-Ragnar Blystad Pille Sooväli Jiban Kumar Kundu Mark Gantsovski Jim Nygren Hervé Lecoq Eric Verdin Carl Jonas Jorge Spetz Lucie Tamisier Erkki Truve Sebastien MassartAbstract
High-throughput sequencing technologies were used to identify plant viruses in cereal samples surveyed from 2012 to 2017. Fifteen genome sequences of a tenuivirus infecting wheat, oats, and spelt in Estonia, Norway, and Sweden were identified and characterized by their distances to other tenuivirus sequences. Like most tenuiviruses, the genome of this tenuivirus contains four genomic segments. The isolates found from different countries shared at least 92% nucleotide sequence identity at the genome level. The planthopper Javesella pellucida was identified as a vector of the virus. Laboratory transmission tests using this vector indicated that wheat, oats, barley, rye, and triticale, but none of the tested pasture grass species (Alopecurus pratensis, Dactylis glomerata, Festuca rubra, Lolium multiflorum, Phleum pratense, and Poa pratensis), are susceptible. Taking into account the vector and host range data, the tenuivirus we have found most probably represents European wheat striate mosaic virus first identified about 60 years ago. Interestingly, whereas we were not able to infect any of the tested cereal species mechanically, Nicotiana benthamiana was infected via mechanical inoculation in laboratory conditions, displaying symptoms of yellow spots and vein clearing evolving into necrosis, eventually leading to plant death. Surprisingly, one of the virus genome segments (RNA2) encoding both a putative host systemic movement enhancer protein and a putative vector transmission factor was not detected in N. benthamiana after several passages even though systemic infection was observed, raising fundamental questions about the role of this segment in the systemic spread in several hosts.
Abstract
No abstract has been registered
Authors
Zhibo Hamborg Minrui Wang Sissel Haugslien Astrid Sivertsen Morten Rasmussen Qiaochun* Wang Dag-Ragnar BlystadAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
Virus diseases have been a great threat to production of economically important crops. In practice, the use of virus-free planting material is an effective strategy to control viral diseases. Cryotherapy, developed based on cryopreservation, is a novel plant biotechnology tool for virus eradication. Comparing to the traditional meristem culture for virus elimination, cryotherapy resulted in high efficiency of pathogen eradication. In general, cryotherapy includes seven major steps: (1) introduction of infected plant materials into in vitro cultures, (2) shoot tip excision, (3) tolerance induction of explants to dehydration and subsequent freezing in liquid nitrogen (LN), (4) a short-time treatment of explants in LN, (5) warming and post-culture for regeneration, (6) re-establishment of regenerated plants in greenhouse conditions, and (7) virus indexing.
Abstract
Viral diseases (a biotic stress) and salinity (an abiotic stress) have been/are the two major constraints for sustainable development of the world’s agricultural production including potato. Crops grown in field are often exposed simultaneously to abiotic and biotic stress, and responses of plants to co-stress by two or more factors may differ from those to each of the multiple stresses. Using in vitro cultures, we demonstrated that virus infection (singly and in combination) or salt, and co-stress by virus infection (singly and in combination) and salt significantly reduced growth and microtuber production, and caused severely oxidative cell damage determined by levels of O2·− and methane dicarboxylic aldehyde, and H2O2 localization in situ. Alterations in physiological metabolism by increasing total soluble sugar and free proline, and by decreasing chlorophyll content are responses of potato plantlets to virus infection (singly and in combination) or salt stress and co-stress by virus infection (singly and in combination) and salt. Oxidative cell damage and reduced chlorophyll content caused by virus and/or salt are believed to be responsible for the reduced growth, eventually resulting in decreased tuber yield. Results reported here would help us to better understand possible mechanism of reduced tuber yield by virus infection and/or salt stress.
Abstract
High-throughput sequencing for plant virus diagnosis in Norway
Authors
Jing-Wei Li Min-Rui Wang Hai-Yan Chen Lei Zhao Zhen-Hua Cui Zhibo Hamborg Dag-Ragnar Blystad Qiao-Chun WangAbstract
Availability of and easy access to diverse plant viruses and viroids is a prerequisite in applied and basic studies related to viruses and viroids. Long-term preservation of viruses and viroids is difficult. A protocol was described for long-term preservation of potato leafroll virus (PLRV), potato virus S (PVS), and potato spindle tuber viroid (PSTVd) in cryopreserved shoot tips of potato cv. Zihuabai. Shoot regrowth levels following cryopreservation were higher in 1.5 mm-shoot tips (58–60%) than in 0.5-mm-ones (30–38%). All shoots recovered from 0.5-mm-shoot tips were PVS- and PSTVd-preserved, but none of them were PLRVpreserved. Cryopreservation of 1.5-mm-shoot tips resulted in 35% and 100% of PLRV- and PVS- and PSTVd-preserved shoots. Studies on cell survival patterns and virus localization provided explanations to the varying PLRV-preservation frequencies produced by cryopreservation of the two sizes of shoot tips. Although micropropagation efficiencies were low after 12 weeks of subculture following cryopreservation, similar efficiencies were obtained after 16 weeks of subculture in pathogen-preserved shoots recovered from cryopreservation, compared with the diseased in vitro stock shoots (the control). Pathogen concentrations in the three pathogens-preserved shoots analyzed by qRT-PCR were similar to those in micropropagated shoots. The three pathogens cryopreserved in shoot tips were readily transmitted by grafting and mechanical inoculation to potato plants. PLRV, PVS, and PSTVd represent a diverse range of plant viruses and viroid in terms of taxonomy and infectious ability. Therefore, shoot tip cryopreservation opens a new avenue for long-term preservation of the virus and viroid.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Zhibo Hamborg YeonKyeong Lee Carl Jonas Jorge Spetz Jihong Liu Clarke Astrid Sivertsen Gry Skjeseth Sissel Haugslien Qiaochun* Wang Dag-Ragnar BlystadAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Zhibo Hamborg YeonKyeong Lee Astrid Sivertsen Gry Skjeseth Sissel Haugslien Jihong Liu Clarke Qiao-Chun Wang Dag-Ragnar BlystadAbstract
No abstract has been registered
Abstract
Replication of all positive-sense single-stranded RNA viruses occurs in specific structures in close association with cellular membranes. Targeting of the viral replication complex (RC) to the site of replication is mediated by the interaction of viral-encoded proteins and host factors. Electron microscope studies have shown that Poinsettia mosaic virus (PnMV, family Tymoviridae) infection is associated with the presence of vesicular structures in the chloroplasts, which indicates that the replication of PnMV might occur in association with chloroplast-derived membranes. Using computer assisted homology search, we have identified that the coat protein (CP) of PnMV shows similarity to membrane bound proteins and contains a conserved amino acid sequence motif found in members of the Alb3/Oxa1/YidC protein family. This protein family is involved in the insertion of proteins into intracellular membranes. In this study we carried out localization studies combined with confocal laser microscopy to identify the cellular localization of the PnMV CP. Transient expression of red fluorescent protein (RFP)-tagged PnMV CP in Nicotiana benthamiana protoplast was shown to localize in the chloroplast.
Abstract
No abstract has been registered
Authors
Zhibo Hamborg Gry Skjeseth Abdelhameed Elameen Sissel Haugslien Astrid Sivertsen Jihong Liu Clarke Qiao-Chun Wang Dag-Ragnar BlystadAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Dag-Ragnar Blystad René van der Vlugt Ana Alfaro-Fernández María del Carmen Córdoba Gábor Bese Dimitrinka Hristova Henryk Pospieszny Nataša Mehle Maja Ravnikar Laura Tomassoli Christina Varveri Steen Lykke NielsenAbstract
No abstract has been registered
Authors
Zhibo Hamborg YeonKyeong Lee Carl Jonas Jorge Spetz Jihong Liu Clarke Qiaochun Wang Dag-Ragnar BlystadAbstract
No abstract has been registered
Authors
Ashraful Islam Jihong Liu Clarke Dag-Ragnar Blystad Hans Ragnar Gislerød Sissel Torre Jorunn Elisabeth OlsenAbstract
No abstract has been registered
Authors
Zhibo Hamborg Sissel Haugslien Jihong Liu Clarke Carl Jonas Jorge Spetz Dag-Ragnar Blystad Qing Wang YeonKyeong Lee Astrid H Sivertsen Gry SkjesethAbstract
Chrysanthemum stunt viroid (CSVd) was first reported in US in the 1940s and is widespread in the world wherever chrysanthemum is grown. Cryotherapy of shoot tips, a new biotechnology developed in the recent years, is a novel application of plant cryopreservation techniques that allows pathogen eradication at a high frequency. Existing studies have proven that this technique can efficiently eradicate pathogens such as virus, phytoplasma and bacterium. However, up to now, there has been no report on viroid eradication. In the present study, we attempted to establish a droplet vitrification cryotherapy method for Argyranthemum and to apply it to eradicate CSVd. Results obtained so far demonstrated that cryotherapy of shoot tips alone failed to eradicate CSVd from the infected shoot tips of Argyranthemum maderense ‘Yellow Empire’. Using in situ hybridization of CSVd and histological analysis, we found that CSVd can invade meristematic cells and at the same time, these cells were able to survive following cryotherapy. These findings explained why cryotherapy of shoot tips alone could not be efficient enough to eradicate CSVd from the diseased materials. Further studies combining cold treatment with cryotherapy are under investigation for CSVd eradication.
Authors
M Ashraful Islam Danuse Tarkowska Jihong Liu Clarke Dag-Ragnar Blystad Hans Ragnar Gislerød Sissel Torre Jorunn Elisabeth OlsenAbstract
No abstract has been registered
Authors
Michael Roleda Maria Herrero Celine Rebours Erik Lysøe Christian Guido Bruckner Marte Meland Merete Dees Dag-Ragnar Blystad Stig A. Borgvang Åsbjørn Karlsen Arne Hermansen Margarita Novoa-GarridoAbstract
No abstract has been registered
Authors
Michael Roleda Maria Herrero Celine Rebours Erik Lysøe Christian Guido Bruckner Marte Meland Merete Dees Dag-Ragnar Blystad Stig A. Borgvang Åsbjørn Karlsen Arne Hermansen Margarita Novoa-GarridoAbstract
No abstract has been registered
Authors
Biao Wang Jing-Wei Li Zhibo Hamborg Ren-Rui Wang Yan-Li Ma Dag-Ragnar Blystad E.R. Joachim Keller Qiao-Chun WangAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Zhibo Zhang Y Lee Sissel Haugslien Astrid H Sivertsen Gry Skjeseth Jihong Liu Clarke Carl Jonas Jorge Spetz Q Wang Dag-Ragnar BlystadAbstract
No abstract has been registered
Authors
Zhibo Hamborg Sissel Haugslien Y Lee Astrid H Sivertsen Gry Skjeseth Jihong Liu Clarke Carl Jonas Jorge Spetz QC Wang Dag-Ragnar BlystadAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Camilla Østerud Ashraful Islam Jorunn Elisabeth Olsen Dag-Ragnar Blystad Sissel Torre Trine Hvoslef-Eide Jihong Liu ClarkeAbstract
No abstract has been registered
Authors
Camilla Østerud M Ashraful Islam Jorunn Elisabeth Olsen Dag-Ragnar Blystad Sissel Torre Trine Hvoslef-Eide Jihong Liu ClarkeAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Ashraful Islam Henrik Lütken Sissel Haugslien Sissel Torre Jorunn Elisabeth Olsen Dag-Ragnar Blystad Søren K. Rasmussen Jihong Liu ClarkeAbstract
No abstract has been registered
Authors
M Ashraful Islam Henrik Lütken Sissel Haugslien Sissel Torre Jorunn Elisabeth Olsen Dag-Ragnar Blystad Søren K. Rasmussen Jihong Liu ClarkeAbstract
No abstract has been registered
Authors
Ashraful Islam Henrik Lütken Sissel Haugslien Hege Særvold Steen Dag-Ragnar Blystad Sissel Torre Jakub Rolcik Søren K. Rasmussen Jorunn Elisabeth Olsen Jihong Liu ClarkeAbstract
No abstract has been registered
Authors
M Ashraful Islam Henrik Lütken Sissel Haugslien Dag-Ragnar Blystad Sissel Torre Jakub Rolcik Søren Rasmussen Jorunn Elisabeth Olsen Jihong Liu ClarkeAbstract
Euphorbia pulcherrima, poinsettia, is a non-food and non-feed vegetatively propagated ornamental plant. Appropriate plant height is one of the most important traits in poinsettia production and is commonly achieved by application of chemical growth retardants. To produce compact poinsettia plants with desirable height and reduce the utilization of growth retardants, the Arabidopsis SHORT INTERNODE (AtSHI) gene controlled by the cauliflower mosaic virus 35S promoter was introduced into poinsettia by Agrobacterium-mediated transformation. Three independent transgenic lines were produced and stable integration of transgene was verified by PCR and Southern blot analysis. Reduced plant height (21–52%) and internode lengths (31–49%) were obtained in the transgenic lines compared to control plants. This correlates positively with the AtSHI transcript levels, with the highest levels in the most dwarfed transgenic line (TL1). The indole-3-acetic acid (IAA) content appeared lower (11–31% reduction) in the transgenic lines compared to the wild type (WT) controls, with the lowest level (31% reduction) in TL1. Total internode numbers, bract numbers and bract area were significantly reduced in all transgenic lines in comparison with the WT controls. Only TL1 showed significantly lower plant diameter, total leaf area and total dry weight, whereas none of the AtSHI expressing lines showed altered timing of flower initiation, cyathia abscission or bract necrosis. This study demonstrated that introduction of the AtSHI gene into poinsettia by genetic engineering can be an effective approach in controlling plant height without negatively affecting flowering time. This can help to reduce or avoid the use of toxic growth retardants of environmental and human health concern. This is the first report that AtSHI gene was overexpressed in poinsettia and transgenic poinsettia plants with compact growth were produced.
Authors
Ashraful Islam Sissel Haugslien Dag-Ragnar Blystad Sissel Torre Jorunn Elisabeth Olsen Henrik Lütken Jihong Liu ClarkeAbstract
No abstract has been registered
Authors
Ashraful Islam Sissel Haugslien Dag-Ragnar Blystad Sissel Torre Jorunn Elisabeth Olsen Henrik Lütken Jihong Liu ClarkeAbstract
Poinsettia is one of the most important potted ornamentals for Christmas. Appropriate plant height is an important trait in poinsettia production. Concern about the negative effects of chemical growth retardants has limited their availability and use. Generation of compact poinsettia plants by genetic transformation has become a promising approach.
Authors
M Ashraful Islam Goutam Kuwar Jihong Liu Clarke Dag-Ragnar Blystad Hans Ragnar Gislerød Jorunn Elisabeth Olsen Sissel TorreAbstract
Abstract Strict control of morphogenesis is essential in production of potted poinsettia. Commonly, this is obtained by the use of plant growth retardants (PGRs), often in combination with early morning temperature drops. Due to negative effects on human health and the environment, the use of PGRs is becoming restricted. Also, energy-saving growth regimes and periods of high temperatures limit effective use of temperature drops. In the present study the use of a high proportion of blue (B) light provided by light emitting diodes [LEDs, 20% blue (B), 80% red (R)] was compared with traditional high pressure sodium (HPS) lamps (5% B) providing similar phytochrome photostationary state to produce compact poinsettia plants. Both in the greenhouse and growth chamber, all cultivars were 20–34% shorter for LED compared to HPS grown plants. Also, leaf and bract area as well as chlorophyll content and total dry matter accumulation were lower under LED. The LED did not delay bract color formation, visible cyathia and flowering compared to HPS, and no difference in post production performance (cyathia/bract abscission or necrosis) between the two light treatments was found. The effect of end of day-red (EOD-R) lighting combination with LED and HPS supplemental lamps during the photoperiod in the greenhouse was also investigated. Reduced stem extension (13%) was observed under HPS only and for one of the two cultivars tested, whereas under the LED regime, there was no effect of EOD-R lighting.
Authors
Camilla Østerud M. Ashraful Islam Jorunn Elisabeth Olsen Dag-Ragnar Blystad Sissel Torre Anne Kathrine Hvoslef-Eide Jihong Liu ClarkeAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
M. Ashraful Islam Henrik Lütken Sissel Haugslien Sissel Torre Jorunn Elisabeth Olsen Dag-Ragnar Blystad Søren K. Rasmussen Jihong Liu ClarkeAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
M. Ashraful Islam Henrik Lütken Sissel Haugslien Sissel Torre Jorunn Elisabeth Olsen Dag-Ragnar Blystad Søren Rasmussen Jihong Liu ClarkeAbstract
No abstract has been registered
Authors
Carl Jonas Jorge Spetz Jihong Liu Clarke Merete Dees Sissel Haugslien Roar Moe Dag-Ragnar BlystadAbstract
No abstract has been registered
Authors
Dag-Ragnar BlystadAbstract
No abstract has been registered
Authors
Dag-Ragnar BlystadAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Jihong Liu Clarke Carl Jonas Jorge Spetz Sissel Haugslien Merete Dees Roar Moe Dag-Ragnar BlystadAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Kirsten Bundgaard Muath K Alsheikh Sissel Haugslien G Adam F. Dale Dag-Ragnar Blystad Carl Jonas Jorge SpetzAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Dag-Ragnar Blystad S. L. Nielsen A. O. Alfaro-Fernandéz Gábor Bese Dimitrinka Hristova Henryk Pospieszny Maja Ravnikar Maryjean Schenk Laura Tomassoli Christina Varveri Kari Ørstad Carl Jonas Jorge Spetz René van der VlugtAbstract
No abstract has been registered
Authors
Jihong Liu Clarke Carl Jonas Jorge Spetz Sissel Haugslien Merete Dees Roar Moe Dag-Ragnar BlystadAbstract
No abstract has been registered
Authors
Carl Jonas Jorge Spetz Jihong Liu Clarke Merete Dees Sissel Haugslien Roar Moe Dag-Ragnar BlystadAbstract
No abstract has been registered
Authors
Inge M. Hanssen Rick Mumford Dag-Ragnar Blystad Isabel Cortez Beata Hasiów-Jaroszewska Dimitrinka Hristova Israel Pagán Ana-Maria Pereira Jeff Peters Henryk Pospieszny Maja Ravnikar Ineke Stijger Laura Tomassoli Christina Varveri René van der Vlugt Steen Lykke NielsenAbstract
No abstract has been registered
Authors
Jihong Liu Clarke Carl Jonas Jorge Spetz Sissel Haugslien Shaochen Xing Merete Dees Roar Moe Dag-Ragnar BlystadAbstract
Agrobacterium-mediated transformation for poinsettia (Euphorbia pulcherrima Willd. Ex Klotzsch) is reported here for the first time. Internode stem explants of poinsettia cv. Millenium were transformed by Agrobacterium tumefaciens, strain LBA 4404, harbouring virus-derived hairpin (hp) RNA gene constructs to induce RNA silencing-mediated resistance to Poinsettia mosaic virus (PnMV). Prior to transformation, an efficient somatic embryogenesis system was developed for poinsettia cv. Millenium in which about 75% of the explants produced somatic embryos. In 5 experiments utilizing 868 explants, 18 independent transgenic lines were generated. An average transformation frequency of 2.1% (range 1.2-3.5%) was revealed. Stable integration of transgenes into the poinsettia nuclear genome was confirmed by PCR and Southern blot analysis. Both single- and multiple-copy transgene integration into the poinsettia genome were found among transformants. Transgenic poinsettia plants showing resistance to mechanical inoculation of PnMV were detected by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). Northern blot analysis of low molecular weight RNA revealed that transgene-derived small interfering (si) RNA molecules were detected among the poinsettia transformants prior to inoculation. The Agrobacterium-mediated transformation methodology developed in the current study should facilitate improvement of this ornamental plant with enhanced disease resistance, quality improvement and desirable colour alteration. Because poinsettia is a non-food, non-feed plant and is not propagated through sexual reproduction, this is likely to be more acceptable even in areas where genetically modified crops are currently not cultivated.
Abstract
An infectious cDNA clone of a Norwegian isolate of Poinsettia mosaic virus (PnMV) was generated. It consisted of 6,098 nucleotides and encoded a polyprotein of 219.5 kDa. Sequence comparisons indicated that this isolate shared 98.6% (nucleotide) and 97.1% (amino acid) identity with the previously sequenced isolate from Germany. RNA transcripts derived from this cDNA were infectious in Nicotiana benthamiana. However, plants did not present typical PnMV symptoms. Furthermore, RNA transcripts from this cDNA clone were not infectious in poinsettia. Serial propagation of this cDNA clone in N. benthamiana plants restored symptom induction in this host but did not re-establish infectivity in poinsettia.
Abstract
Dette sammendraget beskriver forekomsten av sharkavirus i Norge, både funnet av sharkavirus på Njøs i 1998 og kartleggingsarbeidet i årene 1998-2003.