Chromatographic (GC-MS) and Virological Evaluations of Lavandula Hybrida ‘Alardi’ Infected by Alfalfa Mosaic Virus

In 2005, Lavandula hybrida ‘Alardi’ [Labiatae (Lamiaceae) family] cultivated at the Herb Garden of Casola Valsenio (Ravenna; northern Italy) has been found infected by Alfalfa mosaic virus (AMV). Symptomatic plants showed malformed leaves with yellow areas followed by stunting and poor flowers. AMV was identified by applying PAS-ELISA. Molecular characterization of a 750 bp fragment corresponding to the coat protein revealed that this AMV isolate belonged to subgroup I. Since comparative research concerning the effects of AMV infections on essential oil produced by lavender ‘Alardi’ has not been reported before, this aspect was investigated. The yields of essential oil from the fresh aerial part material were of 8.82ml/kg for AMV-infected and of 13.8ml/Kg for healthy plants respectively. In order to verify qualitative and/or qualitative differences in the composition of the two essential oils obtained, GC-MS analysis has been applied, evidencing a net decrease in monoterpene content (aliphatic and non-alcoholic monoterpenes, in particular) and a 50% increase in sesquiterpene abundance. Moreover, this is the first report of the essential oil profile of L. hybrida ‘Alardi’. From this preliminary study it is evident that: a) AMV can decrease the volatile oil fraction and modify the concentration of some of the main essential oil components and b) the essential oil of lavender ‘Alardi’ is characterized by the presence of 1,8-cineole (52,5%) and sabinene (9,9%) and is almost devoid of linalool and its acetates.