Coconut cadang-cadang viroid Surveillance in Imported Cocos nucifera in Germany

Coconut cadang-cadang viroid (CCCVd) is a highly pathogenic RNA agent listed on the EPPO A1 quarantine list due to its severe impact on coconut and other palm species. This study examined the potential introduction of CCCVd and related viroids through the import of coconut palms (Cocos nucifera) into Germany. Fifteen young coconut plants from various retail and botanical sources were grouped into three pools, each composed of leaf material from five plants, and analyzed via RNA-based metagenomic sequencing. Comprehensive RNA-seq analysis, combining reference-based mapping against known palm viroids and host-depletion followed by de novo assembly and DIAMOND-based taxonomic annotation, revealed no authentic viroid sequences. Neither CCCVd nor related agents such as Coconut tinangaja viroid (CTiVd) were detected. This work represents a first step toward viroid surveillance in imported coconut palms and underscores the value of integrating high-throughput sequencing into early detection protocols for regulated quarantine pathogens.