Molecular and biological characterization of squash leaf curl China virus infecting Phaseolus vulgaris in China

Common bean ( Phaseolus vulgaris ) is one of the most economically vital vegetable crops in China. In June 2024, Phaseolus vulgaris samples displaying symptoms of leaf curling and crinkling were collected from an area adjacent to a pumpkin field in Zhengzhou, Henan Province, China. Full-length viral components were successfully isolated from the diseased Phaseolus vulgaris plants. The genome of the isolated virus was found to be 2,737 nucleotides (nt) in length, sharing the highest sequence similarity (99.3% identity) with that of the squash leaf curl China virus (SLCCNV). The DNA-B component consists of 2,717 nucleotides (nt) and shows the highest sequence similarity (98.5% identity) with the DNA-B segment of SLCCNV-SDZBZ. Pathogenicity assays demonstrated that inoculating Phaseolus vulgaris plants with both SLCCNV and SLCCNB led to the manifestation of typical leaf-curling and crinkling symptoms. The presence of the virus in the inoculated Phaseolus vulgaris plants was confirmed via polymerase chain reaction (PCR). To the best of our knowledge, this is the first report of SLCCNV and SLCCNB infecting Phaseolus vulgaris in China. These findings will contribute to the formulation of more effective management strategies against emerging viral threats.