First report of citrus leaf blotch virus infecting Broussonetia papyrifera (paper mulberry) in South Korea.

Broussonetia papyrifera (paper mulberry) is an economically important species in East Asia used for fiber production, traditional medicine, and ecological restoration. During a field survey, virus-like symptoms, including chlorotic mottling and mosaic were observed in B. papyrifera leaves. High-throughput sequencing of total RNA identified citrus leaf blotch virus (CLBV), a member of the genus Citrivirus within the family Betaflexiviridae. De novo assembly generated an 8698-nt contig showing 86% nt identity with CLBV isolate Ac-MX. The genome contained three open reading frames encoding a replication-associated polyprotein, a movement protein, and a coat protein. RT-PCR and Sanger sequencing confirmed the presence of CLBV. Rapid amplification of cDNA ends validated the genome termini and completed the viral genome sequence, which was deposited in GenBank under accession number PX939710. Phylogenetic analysis based on complete genome sequences placed the B. papyrifera isolate within a clade of CLBV isolates previously reported from Actinidia species. This study represents the first report of CLBV infecting B. papyrifera in South Korea.