Detection and characterization of bean yellow mosaic virus (<i>Potyvirus phaseoluteum</i>) in common bean (<i>Phaseolus vulgaris</i>) from Saskatchewan and Alberta, Canada

Bean yellow mosaic virus (BYMV) is one of the major viruses affecting legumes worldwide. The virus has been documented in various monocot and dicot hosts in addition to legumes. The literature describes nine distinct phylogroups of the virus, which also differ in host specificity. Recombination between members of different phylogroups is suggested to aid in host range expansion. Common bean plants showing virus disease-like symptoms were sampled from Saskatchewan and Alberta in 2023 and 2024. These samples were tested for potyviruses using potyvirus-specific degenerate primers, followed by BYMV and Pea seedborne mosaic virus (PSbMV) -specific primers. One sample from Saskatchewan and the other from Alberta tested positive for BYMV. Near-complete BYMV genomes were generated through next-generation sequencing of the two positive samples. Analysis of the BYMV genomic sequences revealed a high degree of similarity between the two isolates, suggesting a recent common ancestor. Both isolates form a clade within phylogroup II, which comprises other members reported from orchids and legumes. Further recombination analysis indicates that both isolates likely originated from recombination between members of phylogroups V and I. Inoculation experiments demonstrated the susceptibility of major legumes cultivated in the region to the virus. Our findings help assess viral risks and alert growers, extension workers and plant pathologists to monitor for BYMV in the field.