The paper describes first report on detection of hop stunt viroid (HSVd) in Slovenia.
COBISS.SI-ID: 7028857
A viroid disease syndrome that was recently described on Slovenian cultivar ‘Celeia’ was investigated. The disease was transferred using biolistic approach to Czech hop under isolated experimental conditions. A complex of strong symptoms appeared on cultivar ‘Osvald’s 72’ that was quite comparable to cultivar ‘Celeia’; low plant fitness strong stunting, leaf malformation, small (tiny) leaves and frequently visible leaf mosaic, which was not associated with virus infection. Hop stunt viroid (HpSVd) was analyzed in detail in the inoculated Czech hop that survived initial infection. It was confirmed that a population of viroid was detectable in the leaves with a clearly dominant HpSVd cucumber pale fruit viroidlike (HpSVd-cuc) sequence. Besides HpSVd, also traces of truncated Citrus viroid (CVd IV) were detected in surviving biolistically infected hop samples. In some samples, HpSVd was detectable by Northern blots, but not by RT PCR, suggesting some viroid sequence change(s) upon adaptation in hop. An expression of several pathogenesisassociated marker genes were investigated. It was found that experimentally induced viroid syndrome in ‘Osvald’s 72’ led to gene deregulation and especially to strong depression of HlbHLH2 transcription factor participating in metabolome regulation in hop.
COBISS.SI-ID: 632716
Newly emerging or re-emerging diseases are a constant and significant threat to agricultural production, so prompt and accurate identification of the causative agents is required for rapid and appropriate disease management. Classical methods of pathogen detection can be successfully supplemented by next-generation sequencing (NGS), whereby sequence analysis can help in the discovery of new or emerging diseases. In 2007, hop growers in Slovenia reported the appearance of severely stunted hop plants, a phenomenon that spread rapidly within hop gardens and among farms. Classical diagnostic methods were unable to detect a new pathogen; therefore, single step high-throughput parallel sequencing of total RNA and small RNAs from plants with and without symptoms was employed to identify a novel pathogen. The sequences were assembled de novo and also mapped to reference genomes, resulting in identification of a novel sequence of Citrus bark cracking viroid (CBCVd) in the stunted hop plants. Furthermore, the presence of this novel pathogen on hop was confirmed by RT-PCR analysis of 59 plants with symptoms from 15 hop gardens, representing the main outbreak locations identified by systematic disease monitoring, and small RNA Illumina sequencing of the bulked RNA sample. The high infectivity of the newly identified CBCVd was also confirmed by biolistic inoculation of two hop cultivars, which developed aggressive symptoms in controlled conditions. This study shows the feasibility of deep sequencing for the identification of causative agents of new diseases in hop and other plants.
COBISS.SI-ID: 8056185
Results were actively presented at several conferences as oral or poster presentations: JAKŠE, Jernej, RADIŠEK, Sebastjan, GUČEK, Tanja, POKORN, Tine, MATOUŠEK, Jaroslav, JAVORNIK, Branka. Viroid razpokanosti skorje agrumov (CBCVd) nov nevaren patogen na hmelju = Citrus bark cracking viroid (CBCVd) as a new aggressive hop pathogen. V: 12. slovensko posvetovanje o varstvu rastlin z mednarodno udeležbo, Ptuj, 3.-4. marec 2015. TRDAN, Stanislav (ur.). Izvlečki referatov = Abstract volume. Ljubljana: Društvo za varstvo rastlin Slovenije: = Plant Protection Society of Slovenia, 2015, str. 63-64. [COBISS.SI-ID 8115321] POKORN, Tine, ŠTAJNER, Nataša, RADIŠEK, Sebastjan, JAVORNIK, Branka, JAKŠE, Jernej. Viroid derived small RNAs can cause change of expression in selected genes of hops. V: Plant and Animal Genome XXIII. [s.l.: s.n.], 2014-2015, p1067. https://pag.confex.com/pag/xxiii/webprogram/Paper15000.html. [COBISS.SI-ID 8109433] POKORN, Tine, RADIŠEK, Sebastjan, JAVORNIK, Branka, ŠTAJNER, Nataša, JAKŠE, Jernej. Viroid-derived small RNA (vd-sRNA) target identification in hop. V: DOLENC KOCE, Jasna (ur.), URBANEK KRAJNC, Andreja (ur.), GREBENC, Tine (ur.). Knjiga povzetkov = Book of abstracts. Ljubljana: Slovensko društvo za biologijo rastlin: = Slovenian Society of Plant Biology, 2014, str. 57. [COBISS.SI-ID 7996025] RADIŠEK, Sebastjan, GUČEK, Tanja, JAKŠE, Jernej, KNAPIČ, Vlasta, BENKO-BELOGLAVEC, Anita, PAVLIČ, Ema, MATOUŠEK, Jaroslav, JAVORNIK, Branka. Appearance and management of hop stunt disease in Slovenia. V: 14th Mediterranean Phytopathological Union (MPU) Congress [and] International Society of Mycotoxicology (ISM) Congress, 25-29 August 2014 Istanbul, Turkey. HEPERKAN, Dilek (ur.), DASKAYA-DIKMEN, Ceren (ur.), ERTUGRUL-CENGIZ, Sibel (ur.). Plant health management for ensuring food security, safety and quality in the Mediterranean area : challenges and prospects : [abstract book]. Istanbul: Istanbul Technical University, Chemical & Metallurgical Engineering Faculty, Department of Food Engineering, 2014, str. 131. [COBISS.SI-ID 654476] JAKŠE, Jernej, POKORN, Tine, RADIŠEK, Sebastjan, JAVORNIK, Branka. NGS sequencing for new phytopathogen discovery. V: Casym Training Event Systems Medicine of Multifactorial Disorders Workshop & Tutorial and 8th CFGBC Symposium, Ljubljana, 12-15 June 2013. AČIMOVIČ, Jure (ur.), PROSENC, Uršula (ur.), JUVAN, Peter (ur.). Book of abstracts. Ljubljana: Faculty of Medicine, 2013, str. 11. [COBISS.SI-ID 7668601] JAKŠE, Jernej, POKORN, Tine, RADIŠEK, Sebastjan, JAVORNIK, Branka. Novel viroid in hops identified by massive-scale rna sequencing. V: International conference [of the] Plant diseases and resistance mechanisms, Vienna, Austria, 20-22 February 2013 : programme and abstracts. Vienna: VIPCA - Vienna International Plant Conference Association, [2013], str. 51. [COBISS.SI-ID 7470713] RADIŠEK, Sebastjan, PERSOLJA, Jolanda, JAKŠE, Jernej, JAVORNIK, Branka, MATOUŠEK, Jaroslav, PAVLIČ, Ema, KNAPIČ, Vlasta. Pojav viroidne zakrnelosti hmelja v Sloveniji = Occurence of hop stunt disease in Slovenia. V: TRDAN, Stanislav (ur.). Izvlečki referatov = Abstract volume. Ljubljana: Društvo za varstvo rastlin Slovenije: = Plant Protection Society of Slovenia, 2013, str. 48. [COBISS.SI-ID 7476089] RADIŠEK, Sebastjan, OSET, Matej, ČERENAK, Andreja, JAKŠE, Jernej, KNAPIČ, Vlasta, MATOUŠEK, Jaroslav, JAVORNIK, Branka. Research activities focused on hop viroid diseases in Slovenia. V: SEIGNER, Elisabeth (ur.). Proceedings of the Scientific Commission [of the] CICH - IHB - IHGC, International Hop Growers` Convention, Kiev, Ukraine, 4-9 June 2013, (Proceedings of the Scientific Commission, ISSN 1814-2192, 2013). Wolnzach: Scientific Comission, I.H.G.C., 2013, str. 58. [COBISS.SI-ID 7617913] POKORN, Tine, RADIŠEK, Sebastjan, JAVORNIK, Branka, JAKŠE, Jernej. Using small RNA technology to identify viroids on hop. V: SEIGNER, Elisabeth (ur.). Proceedings of the Scientific Commission [of the] CICH - IHB - IHGC,
COBISS.SI-ID: 7618425
Viroids are the smallest plant pathogens; their genome is short, single-stranded, non-coding, circular RNA molecule. They can infect cultural and ornamental plants and cause diseases that have a major economical impact. The plants defence against viroid pathogens is based on the mechanism of RNA silencing. Viroids can avoid this mechanism due to compact secondary structure and localization in organelles. Furthermore they can turn mechanism of RNA silencing in their favour, therefore they are able to silence selected host genes. By using the RNA silencing mechanism viroids can silence genes associated with plant defence, signal transmission, cell wall structure and many others. This leads to the development of symptoms such as dwarfing, leaf curling, stem and leaves necrosis, distortion of the fruits, in some cases, plants may also die. In order to facilitate disease prevention, it is crucial to understand the mechanism of viroid infection.
COBISS.SI-ID: 8084089