Molecular Plant Pathology On-line [http://www.bspp.org.uk/mppol/1997/0624karan]

Association of Banana Bunchy Top Virus DNA Components 2 to 6 with Bunchy Top Disease.

Mirko Karan1 , Robert M Harding, James L Dale*

Centre for Molecular Biotechnology, School of Life Sciences, Queensland University of Technology, GPO Box 2434, Brisbane 4001, Queensland, Australia.

Current address: 1 Biochemistry Department, School of Molecular Sciences, James Cook University of North Queensland, Townsville 4811, Queensland, Australia.
Fax: +61 77 251 294, Email: Mirko.Karan@jcu.edu.au

Corresponding author: Professor James L Dale, Centre for Molecular Biotechnology, School of Life Sciences, Queensland University of Technology, GPO Box 2434, Brisbane 4001, Queensland, Australia.
Telephone: +61 7 3864 2819 Fax: +61 7 3864 1534 email: j.dale@qut.edu.au

Banana bunchy top virus (BBTV) has a genome consisting of six different ssDNA components that have been identified in an Australian BBTV isolate. Further, BBTV DNA-1 has previously been shown to be present in all BBTV isolates tested from ten countries. The sequences of BBTV DNA-1 from the different isolates divided into two groups, the South Pacific group and the Asian group. We have now demonstrated, by Southern analysis, PCR and sequencing, that BBTV DNA-2, 3, 4, 5 and 6 are present in all isolates tested from eight countries suggesting that BBTV DNA-1 to 6 are integral components of the BBTV genome. The sequences of BBTV DNA-6 from the different isolates also divided into the two groups, the South Pacific group and the Asian group. Interestingly, there was far greater sequence variability between the sequences within the Asian group than those within the South Pacific group of isolates suggesting that either BBTV has been present in bananas in this region for a longer period or there has been more than one introduction of BBTV into bananas from another host in this region.