First Report of Dasheen Mosaic virus in Elephant Foot Yam in India

Dasheen mosaic virus (Genus Potyvirus) (DsMV) has been reported from around the world, mainly in the tropics, where it infects members of the Araceae (Brunt et al., 1996). Hosts of DsMV include important root and tuber crops such as Alocasia, Colocasia and Xanthosoma or ornamentals Caladium, Dieffenbachia and Philodendron. In India, elephant foot yam Amorphophallus paeonifolius (Dennst.) Nicolson, formerly known as Amorphophallus campanulatus, produces an edible corm which is widely cultivated in a number of states from West Bengal to Tamilnadu (Fig.1). Its importance to rural livelihoods is highlighted by the fact that it is included in the National Germplasm Evaluation Programme for tuber crop improvement. On the Students' Instructional Farm of BCKV in Mohanpur, leaves of some elephant foot yams showed mosaic symptoms and newly emerging leaves were deformed and pale yellow in colour with parallel chlorotic streaks (Fig.2).

Samples of asymptomatic and affected leaves were collected and sent to the Department of Plant Pathology, IACR-Rothamsted UK. Sap was extracted from leaves and stained with 2% phosphotungstic acid pH7.0 and examined in an electron microscope where filamentous potyvirus-like particles (750 x 12nm) were observed, no particles were seen in extracts of asymptomatic leaves. Expressed sap was then subjected to immunosorbent electron microscopy, by the method of Adams, Jones & Swaby (1988) using a polyclonal antiserum to DsMV kindly provided by Dr N J Spence (HRI Wellesbourne). Particles from the samples were trapped (Fig. 3) and decorated, confirming their identity as DsMV. This is the first report of DsMV infecting Elephant foot yam in India and our findings have implications for the selection of germplasm in the National Breeding Programme. This investigation was done under a British Council Higher Education Link project between BCKV and IACR - Rothamsted.