First report of Chilli leaf curl virus affecting chilli in India

Chilli (Capsicum annuum) is an important spice crop cultivated throughout India. Leaf curl disease of Chilli has emerged as a serious problem in the Jodhpur district, the major chilli growing area of Rajasthan state. During December 2004, very high disease incidence (up to 100% of plants) was observed in farmer's fields in Narwa and Tinwari villages. The characteristic field symptoms were upward curling, puckering and reduced size of leaves (Fig. 1). Severely affected plants were stunted and produced no fruit. The virus from field samples from Narwa village was transmitted by whitefly (Bemisia tabaci) to 50-100% of chilli test plants, which produced vein clearing, curling and stunting symptoms. Electron microscopic examination of field samples revealed few, typical geminate particles. The presence of a begomovirus was confirmed by polymerase chain reactions (PCR) using the degenerate primers AVF28 5'-GCCCACATYGTC TTYCCNGT-3' and AV29R 5'-GGCTTYCT RT ACATRGG-3', which gave a ca.1.0 kb product. Cloning and sequencing of the PCR product yielded a 995 bp sequence (Acc. No. DQ445255). A BLAST search of GenBank revealed close similarity of the sequence with the intergenic region and part of the replication initiator protein, AV1 and AV2 genes of Chilli leaf curl virus-[Pakistan: Multan] (ChiLCuV-[Pk:Mul]; AF336806) reported from Pakistan (Shih et al., 2003).

In India, Tomato leaf curl New Delhi virus (ToLCNDV) was recently shown to be associated with chilli leaf curl disease occurring in Lucknow (Khan et al., 2006). Two more Begomovirus species, Cotton leaf curl Multan virus (CLCuMV) (Hussain et al., 2003) and Pepper yellow leaf curl Indonesia virus (PepYLCIDV) (Tsai et al., 2006), have been reported to be associated with chilli leaf curl in Pakistan and Indonesia respectively. Sequence analysis showed that the virus isolated from Jodhpur was distantly related (59.1-67.9 % identity) to CLCuMV, PepYLCIDV and ToLCNDV. However, it shared 96.5% identity with ChiLCuV-[Pak:Mul]. Given the close sequence identity with ChiLCuV-[Pk:Mul], the virus isolated from Jodhpur is considered to be ChiLCuV. To our knowledge this is the first report of ChiLCuV affecting chilli in India. Our findings along with the recent report of Khan et al. (2005) show that chilli leaf curl in India is caused by more than one begomovirus.