Whole-genome sequence analysis of zucchini yellow mosaic virus isolated from Cucurbita and Luffa.

Zucchini yellow mosaic virus (ZYMV) is a major pathogen that negatively affects cucurbit crops. To elucidate the molecular characteristics and evolutionary dynamics of ZYMV in China, ZYMV was isolated from Cucurbita and Luffa samples collected from plants exhibiting typical yellow mosaic symptoms in Tai'an, Shandong Province, and its complete genome sequence was determined. Using reverse transcription PCR combined with rapid amplification of cDNA ends, the full-length genome sequences of two isolates obtained from Luffa and Cucurbita (ZYMV-sg, GenBank accession no. PV007922; ZYMV-ng, GenBank accession no. PV007923) were determined. Both genomes were 9,592 nt in length (excluding the poly(A) tail). The genomes encoded a polyprotein of 3,080 amino acids and exhibited a genomic organization typical of members of the family Potyviridae. Phylogenetic analysis revealed that both isolates were most closely related to Chinese isolates and formed a distinct subclade within the major group B-I. Recombination analysis identified specific recombination events in ZYMV-ng, indicating that genetic recombination contributed to the molecular evolution of ZYMV. Further analyses suggested that purifying selection played a dominant role in shaping ZYMV evolution. These findings provide important molecular insights into the genomic structure, phylogenetic relationships, and sequence evolution of ZYMV isolates from Cucurbita and Luffa in China and provide a basis for further research on virus-host interactions and the development of targeted disease control strategies.