Identification of an Isolate of Potato virus Y-Tuber Necrotic Strain on Clary Sage (Salvia sclarea).

In 1999, clary sage plants (Salvia sclarea L.) at the Herb Garden of Casola Valsenio (Emilia-Romagna Region, northern Italy) exhibited malformed leaves with yellow spots and line patterns. Sap from leaves of symptomatic sage plants caused symptoms in inoculated Chenopodium amaranticolor Coste et Reyn. plants (local chloro-necrotic lesions developed 7 to 10 days after inoculation) and Nicotiana tabacum L. 'White Burley' and 'Samsun' plants (systemic veinal necrosis developed ≈ 2 weeks after inoculation). Leaves from symptomatic sage plants tested positive for Potato virus Y (PVY) based on immunoelectron microscopy, gold-labeled decoration, and protein A sandwich enzyme-linked immunosorbent assay (ELISA), using antiserum to PVY (PVAS 50a, American Type Culture Collection, Manassas, VA). Double-antibody sandwich-ELISA, using specific monoclonal antibodies (BioReba AG, Reinach, Switzerland) to the tobacco veinal necrosis strain group of PVY (PVY-N), revealed that the PVY isolate from sage belonged to this group. Immunocapture-reverse transcription-polymerase chain reaction, using specific primers for PVY and the tuber necrotic strain of PVY (PVY-NTN), further classified the sage isolate as PVY-NTN (1). PVY-NTN causes serious damage to potato in Europe. Clary sage, one of the most important aromatic plants cultivated worldwide as a source of essential oils, represents a new natural host of PVY-NTN. Reference: (1) H. L. Weidemann and E. Maiss. J. Plant Dis. Prot. 103:337, 1996.