Molecular variability of banana mild mosaic virus (BanMMV)

Banana mild mosaic virus (BanMMV) is currently one of the major viral constraints for Musa germplasm exchanges, since the virus is propagated vegetatively. Current data show that synergistic infections with banana streak virus (BSV) or cucumber mosaic virus (BSV) can lead to severe necrotic symptoms, although single infections by BanMMV cause no or only very mild symptoms. Very few data are currently available on the epidemiology of BanMMV. In order to gain insights into it, we have undertaken studies on BanMMV molecular variability. An IC-RTPCR based detection method has been set up. Amplification products, located within the RdRp gene, have been cloned and sequenced for over 35 different accessions originating from CIRAD-Guadeloupe's Musa collection, with at least 3 clones sequenced for each accession. Sequence comparisons show that an important molecular variation exists between isolates originating from distinct accessions. On the other hand, sequences originating from a given accession are generally very conserved. Our results tend to indicate that BanMMV could be preferentially but not exclusively transmitted vegetatively. (Texte intégral)