Detection of Citrus exocortis viroid on Solanum jasminoides plantlets from an Austrian nursery

Abstract

Austrian Agency for Health and Food Safety (AGES), Institute of Plant Health, Spargelfeldstrasse. 191, A-1220 Vienna, AustriaInSeptember2009,thirtyplantletsofSolanumjasminoideswerereceivedfrom a commercial nursery in Upper Austria. The material originatedfrom a breeding company in Germany for growing-on and propagatingbefore reselling. The plantlets did not show any symptoms of a diseaseand were routinely tested for Potato spindle tuber viroid (PSTVd). Leafsamples were randomly taken from several plantlets and total RNA wasextractedwithacommercialRNAextractionkit(RNeasyPlantMiniKit,Qiagen),accordingtothemanufacturer’sinstructions.Aone-stepreversetranscription (RT)-PCR (Qiagen) was performed for the pospiviroidgen-eric detection using Pospi1 primers (Verhoeven et al., 2004). In parallel aRT-PCRwascarriedoutforthedetectionofPSTVdwiththeprimerspub-lished by Shamoul etal.(1997). The generic pospiviroid RT-PCR yieldedanampliconofexpectedsize.However,noPCRproductwasobtainedforPSTVd.Sequencing of the Pospi1 amplicon (partial sequence) showed a 97%identity with those of two Citrusexocortis viroid(CEVd) isolates from S.jasminoides (GenBank Accession Nos. AM920649 and AM774357).Total RNA was further tested with specific primers to CEVd (O¨ nelge,1997) and the full genome length (374 bp) was sequenced (GU300810),which exhibited 98% identity with those CEVd isolates previously men-tioned. The mismatches were on four positions: an insertion at base 49and substitutions at bases 72, 73 and 131 compared to AM920649sequence; and substitutions at the positions 73, 131, 316 and 318 com-pared to the AM774357 sequence. This is the first report of CEVd on S.jasminoides in Austria, although this pathogen had been alreadydescribedoccurringinS.jasminoidesinotherEuropeancountries(Verho-evenetal.,2008).Resultssuggest thepotentialriskofsymptomlessinfec-tion of ornamental Solanaceae by CEVd as a source of infection for cropplants,andtheurgencyofmeasurestobetakentocontroldiseasespread.AcknowledgementsWe would like to thank Mr. Ko Verhoeven (PPS, NL) for the valuablecommentsandhelpinthesequenceinterpretation.References