Identification of a potyvirus associated with mosaic disease of Narcissus sp. in India

Abstract

Narcissus tazetta cv. Paperwhite is an important ornamental for the floriculture industry. Narcissus is susceptible to three members of genus Potyvirus, namely Narcissus yellow stripe virus, Narcissus late season yellows virus and Narcissus degeneration virus, plus Narcissus latent virus (genus Macluravirus, family Potyviridae). A disease characterized by severe mosaic and light green to yellow leaf stripes, was observed on Narcissus in an experimental plot at the National Botanical Research Institute, Lucknow. Affected plants also showed extreme reduction in their growth, and loss of yield and bloom quality. Total RNA was extracted from 100 mg of leaf tissue as described by Gibbs & MacKenzie (1997). RT-PCR was performed with potyvirid specific primers Pot1 and Pot2 (Gibbs & MacKenzie, 1997) to amplify part of the NIb gene, the coat protein (CP) gene and the 3′ untranslated region (UTR). The amplified DNA fragment of c. 1·5 kb was cloned into the p-drive cloning vector (QIAGEN) and sequenced (GenBank accession DQ991145). The CP gene nucleotide sequence showed 98% identity with Chinese narcissus potyvirus Chongming isolate (AJ311374·1), 97% with Chinese narcissus potyvirus Zhangzhou isolate (AJ311373·1) and 95% with Lycorsis potyvirus (AF511486·1). The 3′-UTR (148 nt.) shared 100% identity with the Chinese narcissus Chongming and Zhangzhou isolates and 97% identity with Lycoris potyvirus (AF511486·1). Earlier investigations in India (Aminuddin et al., 1989, 1999), based mainly on biological, serological and electron microscopic properties demonstrated the association of an unidentified potyvirus with severe mosaic disease of Narcissus tazetta. However, nucleotide sequence information (CP gene and 3′ UTR) available in this study clearly established the identity of the associated potyvirus, at the species level, as the virus first recorded as Lycoris potyvirus. This is the first specific identification of a potyvirus from narcissus in India. However, Narcissus spp. are prone to mixed viral infections (Chen et al., 2003) so this potyvirus may not be the sole agent causing the mosaic disease.