Characterization of A New Carlavirus from Gaillardia Aristata

During investigation of Gaillardia aristata breeding material several plants reacted strongly (DAS-ELISA) with a commercially available Chrysanthemum virus B (CVB) antiserum. In order to confirm the identity of the virus, a part of its replicase gene was sequenced, showing just 26% amino acid sequence identity to CVB. This prompted us to determine the entire genome of this virus isolate. The complete genome was 8659 nt in length (excluding poly-A tail) and contained six open reading frames. The genome organisation resembled that of typical carlaviruses. The replicase (70%) and CP (71%) showed the highest aa sequence identities to Phlox virus S (PhVS), being well below the species demarcation threshold of 80%. The remaining ORFs (TGB1-3, NABP) also showed the highest aa sequence identities to PhVS, ranging from 59 (TGB3) to 77% (NABP). In addition, the CVB antiserum was tested with other Carlavirus isolates available at the DSMZ plant virus collection. Besides CVB and the new Carlavirus from Gaillardia, it showed a strong cross-reaction (DAS-ELISA) with isolates of Kalanchoe latent virus, Potato virus S, Passiflora latent virus and Helenium virus S.