New achievements for diagnostics of banana streak virus

Banana streak virus (BSV) remains one of the most challenging viral pathogens of banana to detect and most diagnostic assays rely on serological methods. The BSV capsid protein contains an N-terminal, intrinsically disordered (NID) domain that is surface-exposed on the virion and likely is multifunctional and plays important roles in viral replication and transmission. The immunodominant continuous epitopes on the virion are also located in the NID domain, and therefore this domain is of great interest from a diagnostics perspective. Using chemically synthesized peptides to mimic the continuous epitopes of five BSV species including Banana streak Mysore virus (BSMYV), Banana streak Obino I’Ewai virus (BSOLV), Banana streak Imove’ virus (BSIMV), Banana streak Goldfinger virus (BSGFV) and Banana streak Cavendish virus (BSCAV), antisera have been raised in rabbits, and shown specificity to each virus species and sensitivity in a range of assay formats such as Western Blot, enzyme-linked immunosorbent assay (ELISA), immunosorbent electron microscopy and immunocapture PCR. This work confirmed the applicability of synthesis epitopes/peptides to produce antipeptide antibodies for BSV diagnostics when the native protein is absent. The Oxoford MinION Nanopore sequencing system is a promising new technology for point-of-care diagnostics. We have successfully used this system and generated long reads with greater than 99% accuracy, allowing accurate and sensitive detection of BSV. The long reads allow episomal from endogenous sequences to be differentiated.