Diversidade genética de espécies do vírus das estrias da bananeira (eBSV) em acessos da coleção de germoplasma da Embrapa Mandioca e Fruticultura

Abstract

Bananas are one of the main consumed fruits worldwide playing a relevant social-economic role in many tropical and subtropical countries. Differently from the world scenario, Brazil concentrates its production in cultivars from the Prata subgroup, mainly ‘Prata-Anã’ and ‘Pacovan’, triploid genotypes with ABB genomes. In bananas, it is known that entire or pieces of the BSV genome may be incorporated in bananas with the B genome in its constitution. Therefore, reports of BSV symptoms are common in banana plantations that use these cultivars located in main banana production sites in Brazil which leads to the conclusion of the presence of the sequence of the virus integrated in the B genome, or its local infection by vectors. For the Brazilian banana agrobusiness the use of cultivars free of integrated sequences of the virus is mandatory, which can be obtained by genetic breeding based on crosses and selection of progenies. Therefore, it is important to use tools available capable of identifying viral particles in the banana germplasm to guide the selection of progenitors free of BSV. The objective of the present work was to evaluate the genetic diversity of BSV species in banana accessions in the germplasm bank at Embrapa Cassava and Fruits using species-specific primers (junction, structure and alleles) developed by CIRAD, Montpellier, France. 304 accessions were analyzed in order to identify the main species of BSV (BSGFV-Goldfinger, BSOLV-Obino L ́Ewai e BSIMV-Imové). 142 accessions showed positive for integration of the genome of the vírus (47% of the germplasm evaluated). All accessions of the wild species of banana and those with genome A, were negative; results in agreement with the international literature which associates the integration of the virus only in B genomes. The most frequent viral species in the germplasm collection were BSGFV and BSOLV, present in approximately 40% and 39%, respectively. Besides the species-specific primers, restriction enzymes were also used (dCAPS markers - Derived Cleaved Amplified Polymorphic Sequences) to identify accessions with the B genome presenting infectious or non-infectious viral alleles. Results show that all accessions of the BB genomic group presented infectious alleles for the BSGFV or BSOLV species. Results enabled to estimate the BSV diversity (eBSV) in banana accessions from the BAG-Banana at Embrapa-CNPMF as well as contribute to the application of methodologies for the detection of the virus in its infectious form, avoiding its propagation and potential epidemiological spread.