A New Variant of Cassava Mosiac Virus Causes Mulberry Mosaic Disease in India
Mulberry with typical symptoms characteristic to Gemini virus viz., enations, mosaic, deformed leaves, curling and stunted growth was collected from Thiruvananthapuram district, Kerala, India. The disease is transmitted through mechanical transmission from the sap of the infected plant to disease free mulberry seedlings and indicator plants, Nicotiana tabaccum and N. benthamiana, confirming the presence of a sap transmissible pathogen. The cassava biotype of Bemisia tabaci transmitted the disease with an AAP 24h and IAP 6h. Amplification for the Gemini virus specific primers was obtained from the total DNA isolated from the infected plants. Further with the primers specific for the coat protein gene (cp, AV1 gene of the A genome) and movement protein gene (mp, BC1gene of the B genome) of the ICMV the ~810bp and ~ 860bp specific amplifications were obtained from the Thiruvananthapuram isolate and the plants inoculated with the sap of Thiruvanathapuram isolate and from plants on which vector transmission done using B. tabaci cassava biotype.The amplified samples were sequenced and submitted the nucleotide sequences to NCBI data base, accession code for cp nucleotide sequence is FJ.827040.2 and that for mp nucleotide sequence is HM.138689.1. The two nucleotide sequences showed 98-99% identities and closest relationship with Indian Cassava Mosaic Virus (ICMV) and Sri Lankan Cassava Mosaic Virus (SLCMV). Bemisia tabaci is confirmed as the vector of the disease by transmission studies and obtained amplification of 810 bp with cp primer from the B. tabaci adults of cassava biotype used for transmission studies.