Molecular characterization of Coleus blumei viroids 1 and 3 in Plectranthus scutellarioides in Croatia
Asymptomatic Plectranthus scutellarioides (syn. Coleus blumei) plants of four different cultivars were investigated for the presence of Coleus blumei viroid (CbVd) species (genus Coleviroid, family Pospiviroidae). Cloned and sequenced amplicons obtained by generic coleviroid primers were analyzed for their primary and secondary structure. CbVd-1 was found in one of the coleus cultivars in a single infection and in another cultivar in a mixed infection with CbVd-3. Additionally, CbVd-3 was found in a third coleus cultivar in a single infection. In singly and doubly infected cultivars, both CbVd-1 and CbVd-3 variants displayed higher variability regarding both length and nucleotide composition in a doubly infected cultivar. Sequences from different cultivars showed different phylogenetic grouping suggesting distinct infection sources, probably introduced infected seeds. For all phylogenetic subgroups, characteristic nucleotide changes were identified and their influence on the secondary structure was predicted. The most noticeable structural changes were observed in nucleotide positions 25–26 in CbVd-1 and in the position 138 in CbVd-3 variants. This work includes the first report of coleviroids in Croatia, the second reported coleviroids sequences from Europe and the third report of CbVd-3 in the world enlarging the pool of knowledge on the variability and distribution of viroids in horticultural crops.
KeywordsCbVd-1 CbVd-3 Coleviroids Mixed infection Painted nettle
Part of the research done by Karlo Jezernik and Anamarija Butković shown here was done for completing their master theses. The Department of Biology, Faculty of Science, University of Zagreb administratively and technically supported them. We are grateful for the technical assistance of Darinka Kajić in the greenhouse and Marin Ježić for the preparation of figures.
This study was funded by the University of Zagreb grants to D. Škorić and S. Černi numbers: 20281214, 20282308 and 20283119.
Compliance with ethical standards
This research fully complies with Ethical Standards applicable for this journal and the relevant national and international ethics standards and professional codes of conduct.
Conflict of interest
The authors declare that they have no conflict of interest.
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