Int.J.Curr.Microbiol.App.Sci (2018) 7(11): 1547-1560 1547 Original Research Article https://doi.org/10.20546/ijcmas.2018.711.178 Genetic Diversity of Banana Bunchy Top Virus (BBTV) Prevalent in Assam Causing Banana Bunchy Top Disease Nilakshi Kakati * and P.D. Nath Department of Plant Pathology, Assam Agricultural University, Jorhat-785013, Assam, India *Corresponding author ABSTRACT Introduction Banana, a fruit of great socio-economic significance is the largest fruit crop of India accounting approximately 35 per cent of its total fruit production. India is the largest producer of bananas and plantains with an annual production of 29.78 million tonnes from an area of 0.748 million ha and accounts for 22.15 per cent of the world ’ s production whereas Assam ranks 9 th position in terms of production amongst the twelve banana growing states of India with an annual production of 0.835 mt from an area of 0.054 mha (NRCB website). Banana plantains are subjected to various natural calamities, but diseases in particular, viral diseases constitute a major setback to this crop worldwide. Among viral infections, Banana bunchy top disease (BBTD) is the most serious and devastating disease of Banana (Musa spp.) caused by a multi component ssDNA virus Banana Bunchy Top Virus (BBTV) belongs to the genus Babuvirus and family Nanoviridae (Allen, 1987). Isometric virions of BBTV are approximately 18-20 nm in diameter (Iskra et al., 1997) consist of six circular single stranded DNA molecules (~1kb each) as a part International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 7 Number 11 (2018) Journal homepage: http://www.ijcmas.com Molecular detection of Banana Bunchy Top Virus (BBTV) was carried out using nucleic acid based polymerase chain reaction (PCR) method with six different primer pairs for the six components of BBTV (DNA1 to DNA6) genome. Samples were collected from six banana cultivars exhibiting the characteristic symptoms Banana bunchy top disease from eight districts of Assam viz., Jorhat, Golaghat, Sonitpur, Morigaon, Nagaon, Kamrup Metro, Kamrup Rural and Goalpara. All the primer pairs detected the BBTV positive samples giving a band size of 1111 bp for DNA 1, 1058 bp for DNA 2, 1075 bp for DNA 3, 1046 bp for DNA 4, 1018 bp for DNA 5 and 1089 bp for DNA 6. Results revealed the prevalence of BBTV in all the surveyed banana orchards. Twelve PCR products were partially sequenced and compared with those of BBTV reported previously. The sequence similarity and phylogenetic analysis showed 86.00 to 99.00 per cent similarity with known isolates of Pacific Indian Ocean (PIO) group members of BBTV. However, two isolates showed 94 to 95 per cent similarity with members of South-East Asian (SEA) group of BBTV. Present investigations showed an indication of prevalence of genetic distinctiveness of BBTV Assam isolates with known Indian isolates. Keywords Banana bunchy top virus, Banana bunchy top disease, PCR, Sequence analysis Accepted: 12 October 2018 Available Online: 10 November 2018 Article Info