ABSTRACT Cucurbits are important vegetables used in herbal medicine and culinary traditions throughout the world. The cultivation of cucurbits is affected by a severe leaf curl virus disease in India, primarily caused by the tomato leaf curl New Delhi virus (ToLCNDV) (genus Begomovirus, family Geminiviridae ). In this study, we investigated the seed-borne nature and seed transmission potential of ToLCNDV in four popular cucurbit crops grown in Karnataka State, South India. ToLCNDV was detected in the seeds of three cucurbits: bitter gourd ( Momordica charantia L.), ridge gourd ( Luffa acutangula (L.) Roxb.) and pumpkin ( Cucurbita moschata Duchesne) but not from bottle gourd ( Lagenaria siceraria (Molina) Standl.). PCR analyses detected the virus in the endosperm and embryo of bitter gourd, endosperm of ridge gourd and the outer skin of pumpkin seeds. Investigations on seedling germination and grow-out tests, however, produced negative results by PCR indicating that ToLCNDV isolates in Karnataka are seed-borne but not seed transmissible. However, several other studies from India and other countries have shown the seed transmission potential of other begomoviruses including ToLCNDV. We will discuss the implications of these findings on the potential long-distance dispersal of begomoviruses and their quarantine implications.
Purushotham et al. (Fri,) studied this question.