Molecular diagnosis of emerging begomovirus diseases in cucurbits occurring in northern India

Cucurbits are economically important group vegetable crops cultivated throughout India. The begomovirus associated diseases in cucurbits are emerging problems in India. For rapid and sensitive detection of begomovirus infection in cucurbits, nucleo-diagnostic methods have been developed. The nucleic acids hybridization test using radiolabelled probe to putative coat protein gene of Tomato leaf curl New Delhi virus-[Luffa] (ToLCNDV-[Luf]) detected begomovirus in several cucurbits and whitefly. The method was efficient in detecting begomovirus in crude extracts of field samples. Polymerase chain reaction (PCR) was standardised using primers synthesised from AC1 and AV2 (coat protein [CP]) genes of ToLCNDV-[Luf]. The CP gene based primers successfully detected begomovirus in naturally infected several cucurbits. Both the molecular tools were validated for broad spectrum diagnosis of begomovirus infection in eight cucurbit crops. Present study for the first time detected emergence of begomovirus infection in bottle gourd (Lageneria siceraria), ivy gourd (Coccinia cordifolia), pumpkin (Cucurbita moschata), ridge gourd (Luffa acutangula) and watermelon (Citrullus lanatus) in northern India.