Identification of Banana streak virus species Goldfinger, Imové, Mysore and Obino l’Ewaï in Musa spp. in Cuba

Abstract

Banana streak virus (BSV) species are widespread in Musa spp. They are naturally transmitted by several mealybug species in a semipersistent mode and by activation of endogenous sequences integrated in the genome of Musa balbisiana, one of the progenitors of synthetic and natural hybrids (Dallot et al., 2001). Typical symptoms include yellow streaks on leaves, splitting of the pseudostem and abnormal emergence of the bunch from the middle of the pseudostem, bearing fewer fruits of smaller size (Jones & Lockhart, 1993). Although leaf streaks and pseudostem splitting symptoms have been previously observed in Cuba, BSV species were never identified. Bacilliform particles were observed by immunosorbent electron microscopy in plantain FHIA21 (Font et al., 1998) but the polyclonal antiserum used was raised against several badnavirus species and is therefore not specific to BSV. Given that this virus has never been confirmed in Cuba, field surveys were started in 2007, to study the occurrence, incidence and diversity of BSV species in dessert and cooking banana. Leaf samples were collected nationwide from plants with, and without symptoms, and indexed separately for the four BSV species, Goldfinger (BSGFV), Imové (BSImV), Mysore (BSMysV) and Obino l’Ewaï (BSOLV) by multiplex immunocapture PCR (Le Provost et al., 2006). All four BSV species were detected in several samples each: BSGFV was detected in FHIA25 hybrid (AAB) in Havana, Granma and Pinar del Rio; BSMysV was detected in cv. Yangambi km5 (AAA) in Granma and Santiago de Cuba; BSImV was detected in FHIA25 hybrid in Havana and Pinar del Rio, and in Giant Dwarf Cavendish (AAA) in Ciego de Avila; BSOLV was detected in FHIA18 hybrid (AAAB) in Havana and in FHIA21 hybrid (AAAB) in Havana, Pinar del Rio, Granma, Cienfuegos and Santiago de Cuba. Samples co-infected by species BSGFV and BSImV, were identified in FHIA25 hybrid from Havana and Pinar del Rio whereas samples co-infected by species BSGFV and BSOLV were detected in FHIA21 hybrid from Havana, Pinar del Rio, Granma and Cienfuegos. For each BSV species, a selection of amplification products were cloned and sequenced. The GenBank accession numbers of the sequences reported in this paper are FJ527423–527434. Blast analysis showed that cloned sequences share 96–100% identity with reference sequences AY493509.1 (BSGFV), AB252638.1 (BSImV), AY805074.1 (BSMysV) or AJ002234 (BSOLV). This report presents the first confirmation and identification of BSV species in Cuba. This work was supported by the Guadeloupe Region through its FCR programme and by the French Ministry of Foreign Affairs. Authors are indebted to Professor B.E.L. Lockhart for providing BSV antiserum.