Presence of banana streak virus ol in dessert bananas in Maracay, Venezuela

Symptoms of a virus like disease were observed in dessert banana (Musa AAA group, Cavendish subgroup cv Pineo gigante) plants. These were characterized by broken or continuous chlorotic streaks, or spindle-shaped patterns that were chlorotic at first and then become increasingly dark in colour, and finally resulted in black streaking in older leaves. In two samples, Banana streak virus (BSV) was detected by electron microscopy and immunosorbent electron microscopy. The typing of the BSV isolates was done on partially-purified leaf extracts by immunocapture followed by polymerase chain reaction using isolate-specific oligonucleotide primers and polyvalent BSV antiserum PMx-R2C (Geering et al., 2000). The results showed that BSV strain OL (=BSV-Onne), recently renamed Banana streak Obino L’Ewai virus, BSOLV (A. Geering, personal communication), was present in the two samples from dessert bananas. This is an interesting observation because BSOLV is known to be integrated in the Musa genome and there is evidence that BSOLV infection can arise from these integrated sequences. However, it has recently been showed that the integrated BSOLV sequence occurs in the Musa B genome but not in the Musa A genome (Geering et al., 2001). This implies that BSOLV infection in dessert bananas can arise only from an external source, and suggests that insect vectors are transmitting the virus from plantain (AAB) to dessert bananas. This is the first report of this virus in Maracay, Venezuela.