Study on mosaic disease of sponge gourd (Luffa cylindrica L.) caused by tomato leaf curl New Delhi virus

Mosaic disease of sponge gourd caused by begomovirus becomes a major constraint for its cultivation by farmers with limited resources in India. From field collected symptomatic leaf sample of sponge gourd, full-length DNA-A and DNA-B components were characterized by sequencing of products obtained by RCA. Sequence analysis revealed the presence of a bipartite begomovirus, tomato leaf curl New Delhi virus (ToLCNDV), with two distinct DNA-A molecules having 89.1% identity among themselves, and one DNA-B molecule sharing identity of 96% with earlier reported ToLCNDV isolates from India. Besides, the association of tomato leaf curl New Delhi alphasatellite and tobacco leaf curl Patna betasatellite were also detected. Additionally, presence of ToLCNDV was ascertained through PCR assay in different parts of the fruit viz., pericarp, mesocarp and immature seed. Further, presence of virus in matured seed and seedlings shown through serological assay confirmed its seed borne nature. To our knowledge, this is the first report of seed transmissible nature of ToLCNDV causing mosaic disease on sponge gourd. Moreover, we identified two moderately resistant entries of advanced breeding lines against the mosaic disease through field screening.

Automated summary

Mosaic disease caused by begomovirus is a major problem for farmers cultivating sponge gourd in India. We identified a bipartite begomovirus, tomato leaf curl New Delhi virus (ToLCNDV), in sponge gourd samples. Additionally, we detected the presence of tomato leaf curl New Delhi alphasatellite and tobacco leaf curl Patna betasatellite. We also confirmed the seed transmissible nature of ToLCNDV and identified two moderately resistant lines through field screening.