Comparative analysis of beet western yellows virus detection methods: Development and validation of a novel real-time RT-PCR assay also targeting beet leaf yellowing virus

Beet western yellows virus (BWYV – Polerovirus BWYV) is a polerovirus associated with yellowing and stunting symptoms in sugar beet and several other crops. Its close relationship with other beet-infecting poleroviruses, has long complicated accurate diagnosis due to serological cross-reactivity and limited molecular data. To overcome these issues, we developed a novel real-time RT-PCR assay enabling the specific and sensitive detection of BWYV and beet leaf yellowing virus (BLYV – Polerovirus BLYV). The assay was designed from a curated genomic dataset to ensure inclusivity and tested in parallel with validated reference methods, including a semi-generic ELISA and a generic polerovirus RT-PCR. Comprehensive validation following the EPPO PM 7/98(5) standard confirmed the method's high analytical sensitivity, specificity, repeatability, and reproducibility. The assay proved robust to methodological variations and compatible with multiplex diagnostic workflows. Compared with existing approaches, it offers faster, more reliable detection and eliminates cross-reactivity with non-target poleroviruses. This method provides a valuable tool for accurate BWYV surveillance and supports improved management of beet virus yellows in agricultural and phytosanitary contexts.