Molecular characterization of a new Carlavirus detected in German Ulmus laevis (Pall.) by Illumina high throughput sequencing

Abstract

A 150 years old population of 30 European white elms (Ulmus laevis Pall.) in the park of Caputh (federal state Brandenburg, Germany) was monitored regularly since 2010. Trees show a dieback and develop characteristic leaf symptoms such as chlorotic ringspots, mottling and necroses. Previous investigations revealed the presence of particles with flexible morphology. To uncover putative pathogenic viral candidates, Illumina high throughput sequencing was applied and three contigs of a putative Elm carlavirus were obtained. They show 40.1–74.0 % identity with whole genome sequences of members of the genus Carlavirus, family Betaflex-iviridae. Phylogenetic analysis of whole genome and the replicase polyprotein group them together with Elderberry carlavirus A, B and D and Poplar mosaic virus respectively. The analysis of proteins coded within ORF 1-5 show significant characteristics, which are distinc-tive features for carlaviruses. These results suggest strongly the presence of a so far unknown carlavirus in Ulmus laevis.