FIRST REPORT OF ALFALFA MOSAIC VIRUS INFECTING LAVANDULA STOECHAS

• Published in: Journal of plant pathology Vol. 91; no. 4; p. S4.49
• Main Authors: Bellardi, M G, Cavicchi, L, Bozzano, G, Parrella, G
• Format: Journal Article
• Language: English
• Published: 01.12.2009
• Subjects: Alfalfa mosaic virus; Chenopodium quinoa; Lamiaceae; Lavandula; Ocimum basilicum; Phaseolus; Vicia faba; Vigna unguiculata
• ISSN: 1125-4653

Lavandula stoechas L. (family Lamiaceae) also known as French lavender or Spanish lavender, is an attractive perennial shrub with pinkish-purple flowers produced on spikes at the top of slender leafless stems. Actually, this ornamental is one of the most important Lavandula species grown in the Albenga area (Liguria, Northern Italy). In 2008-2009, some L. stoechas potted plants were found to be naturally infected by Alfalfa mosaic virus (AMV). Symptoms consisted of a yellow mottling that appeared first on the oldest leaves. Flowering was apparently normal. AMV was first identified by PAS-ELISA in diseased plants. A few herbaceous hosts were manually inoculated with sap expressed from symptomatic tissues but only Ocimum basilicum (cv. Gigante) developed necrotic line-patterns followed by a bright systemic yellow mosaic. Symptomatic basil was used as starting material for further mechanical transmissions to Vigna unguiculata 'Black eye', Vicia faba and Phaseolus spp. (local brown necrotic lesions), Chenopodium quinoa and C. amaranticolor (systemic chlorotic mosaic and malformations). Restriction profile obtained after RT-PCR-RFLP with BamHI endonuclease of a 750 bp fragment, comprising the viral coat protein gene, revealed that the L. stoechas isolate of AMV belongs to soubgroup I. This study confirms the spreading of AMV subgroup I in other "new" ornamental Lavandula (true species or hybrids) hosts, as recently reported for Lavandula x allardii.