Ekspresowa Ocena Zagrożenia Agrofagiem (Express PRA): Citrus bark cracking viroid (CBCVd)

Poland is the fifth largest producer of hops in the European Union along with Slovenia, Germany, England and the Czech Republic. The crop covers 1423.6 hectares of land (data from the Agricultural and Food Articles Quality Inspection as of 30.06.2015. World production of hops in 2015 amounted to 50 thousand hectares in 19 countries, including 27 thousand hectares in the EU (13 countries). Citrus bark cracking viroid (CBCVd) is widespread in citrus growing regions, making it presumably also occurs on these plants/fruits in Poland. To date, however, it has not been confirmed in Poland of its presence either on hops or citrus plants. In 2007 in Slovenia, in hop crops, in the Šempeter region of the Savinja Valley (for the first time in the European Union), a previously unknown, aggressive disease was found to cause severe stunting of plant growth in hop plantations. In 2011, after diagnostics, Hop stunt viroid (HSVd) was found (Radisek et al. 2012), which was previously described as a pathogen in hop crops (Sasaki and Shikata 1977a, b) causing severe growth stunting (Eastwell and Sano 2009; Sano 2003a, b, c). Using next-generation sequencing (Next Generation Sequencing, NGS), the occurrence of a new viroid in the hop crop - CBCVd - was confirmed. It was previously considered only a pathogen of citrus plants (Semancik and Vidalakis 2005). At the same time, it was also found that the cause of severe disease symptoms on hop plants is CBCVd, which presumably exhibits antagonistic activity against HSVd. CBCVd
has been described as an economically minor citrus viroid that occurs only in countries and regions where citrus is grown. The results obtained in Slovenia showed for the first time the presence of CBCVd on hops and its detrimental effects on plant growth, and expanded the scope of the region in which the viroid can occur. In 2014, viroid was detected on 13 Slovenian hop plantations.