Cucumber Mosaic Virus and their associated satellite RNAs infecting banana (Musa sp. Genomic group AAA) in Côte d’Ivoire : A molecular characterization.

Résumé

In Côte d’Ivoire, banana (Musa sp.) ranks third among exportation products and represents 3% of the Gross Domestic Product with a national production up to 500000 tons in 2019. Banana is subject to numerous disease agents among which viruses cause significant losses. To figure out the impact of viruses in Ivorian industrial banana fields, surveys were conducted in the 7 main banana production departments. A total of 260 leaf fragments presenting viral symptoms were collected and analyzed. From the 65 leaf fragments used for biological indexing, 14 showed symptoms related to Cucumber mosaic virus (CMV). CMV presence was confirmed by double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) using CMV polyclonal antibodies. CMV strains we isolated, appeared to be highly infectious and to produce various symptoms like mosaic, chlorosis, and necrotic spots on Cucumissativus, Cucurbita pepo, and Nicotiana tabacum. Satellite RNAs (SatRNAs) associated with CMV isolates were also detected using reverse transcription polymerase chain reaction (RT-PCR) with a degenerate primer pair. CMV’s coat protein as well as satRNAs was sequenced. Novel Ivorian coat proteins and satRNAs were compared to publicly available sequences. We noticed a single amino acid substitution (Serine to Leucine) at position 73 of the novel coat protein that allowed us to divide Ivorian CMV strains into two groups. Molecular and phylogenetic analysis suggested that Ivorian strains might be classified into CMV Subgroup IA. We also discovered that satellite RNA associated with Ivorian CMVs form a separate clade.