Molecular characterization of a virus causing mosaic disease on withania somnifera

Abstract

Withania somnifera Locally known as ashwagandha, belongs to family Solanaceae. The plant has an important place in different medical systems (Ayurvedic, Allopathic, Unani, Homeopathic etc.) due to its excellent therapeutic properties. W. somnifera possesses a great potential for the treatment of several maladies such as inflammation, impotency, dehydration, cancer, arthritis, Parkinson s disease, rheumatism, memory loss, nervous exhaustion, bone weakness and tension, chronic fatigue, debility, premature ageing, emaciation etc. Pharmaco-chemical analysis of W. somnifera has revealed a very large number of bio-active compounds such as alkaloids and steroidal lactones. At present, 138 withanolides with both and#946; and and#945; side chains has been reported. Major source of withanolides in W. somnifera has been reported to be in its leaves possessing an excellent selective COX-2 inhibitory activity. Ethnic or aqueous extract of the root alone or in combination with other herbal materials is used in many commercial herbal formulations under various trade names such as Mentat, Gerifortate, Pepcaps, Stresscom, Ashwagandharist, Ashwagandha-ghrit etc. W. somnifera is cultivated over an area of 10,780 ha with a production of 8429 tones in India, While the annual demand increased from 7028 tones (2001-02) to 9127 tones (2004-05) necessitating the increase in its cultivation and higher production. A new virus disease was observed on W. somnifera in Aligarh, Lucknow of Uttar Pradesh and Hindaun city of Rajasthan during 2008-09 with significant (15-25%) disease incidence. The virus infection produced mosaic and leaf curl symptoms leading to the reduction in biomass and quality of W. somnifera. Keeping in view the potential of the plant, it was necessary to identify and characterize the causal virus pathogen at molecular level. The study on virus culture, transmission, host range, electron microscopic studies and molecular characterization and studies related to morphological, anatomical and biochemical alterations were performed