Evidence that the proliferation stage of micropropagation procedure is determinant in the expression of Banana streak virus integrated into the genome of the FHIA 21 hybrid ( Musa AAAB)

Abstract

Banana streak virus (BSV) is causing increasing concern in almost every producing area of banana and plantain (Musa spp.) worldwide. This situation appeared partially linked to some breeding lines and micropropagated hybrids. A complete BSV sequence integrated into the genome of a triploid plantain has been recently characterised and it has been hypothesised that it could give rise to infectious virus via recombination. In this study, we evaluated the effect of a routine micropropagation procedure on the expression of BSV in the FHIA 21 tetraploid hybrid. The widespread presence of integrated sequences and the absence of episomal BSV in thirty FHIA 21 "mother plants" selected for micropropagation were first confirmed by specific PCR and IC-PCR tests. The proliferation stage of the procedure, characterised by an intensive production of neoformed buds, appeared determinant in BSV expression whereas the rooting and acclimatisation stages had little or no effect. The duration in culture and the way of subdividing the clumps of proliferation influenced greatly the percentage of episomal BSV infections, reaching 58% of infected micropropagated lines after six in vitro subcultures. These data suggest that the expression of episomal BSV observed during the in vitro procedure is correlated with the presence of an integrated form.

Molecular analysis of gooseberry vein banding associated virus

“…Their infection can lead to development of flecks, freckles, streaks, chlorosis or yellowing along veins, or there may be no visible symptoms whatsoever. In the past decade, badnaviruses have been the subject of increased attention since the discovery of their endogenous sequences in various plant genomes (Geering et al, 2005(Geering et al, , 2011Gayral et al, 2008;Kenyon et al, 2008;Bousalem et al, 2009;James et al, 2011) and risk of their putative spread through infected germplasm and/or activation by an abiotic stress during propagation (Dallot et al, 2001).…”

Evolution of Endogenous Sequences of Banana Streak Virus : What Can We Learn from Banana ( Musa sp.) Evolution?

“…Interspecific hybridization and new genome combinations in plants are associated with EPRV activation in all pathosystems (39,42,53). Cultures under stress conditions, such as wounding for petunia, or in vitro culture for banana, trigger activation of PCVC (53) and BSV (9), respectively. In banana plants, genetic hybridization is another context to study the activation of infectious eBSV for triploid interspecific hybrids (AAB genome) resulting from genetic crosses between the two diploids Musa acuminata cv.…”

Clonagem e purificação de fragmento da proteína capsidial de Banana streak OL virus

“…Para o genoma da bananeira, já foram descritos dois tipos de EPRV relacionados ao BSV: um tipo que contém o genoma completo do vírus e que pode originar partículas virais e causar infecção epissomal; e outro tipo com sequências incompletas do BSV, não relacionadas à manifestação da doença (Jaufeerally-Fakim et al, 2006). A hipótese de que a propagação in vitro pode atuar como desencadeadora da infecção a partir das EPRV ganhou força com estudos realizados por Dallot et al (2001) e Côte et al (2010), ainda que os mecanismos para que tal evento ocorra não sejam entendidos.…”

“…Genótipos resultantes de cruzamentos entre M. acuminata e M. balbisiana, inclusive uma variedade de novos híbridos, mostraram a tendência de produzirem propágulos infectados pelo BSV, mesmo quando são utilizadas plantas assintomáticas na cultura de tecidos (Dallot et al, 2001).…”