Occurrence and regional distribution of melon viruses in Xinjiang Uygur Autonomous Region, China

Xinjiang is a major melon-producing region in China, where viral diseases severely constrain both yield and quality. Despite their importance, the species composition, spatial distribution, and infection dynamics of melon viruses remain incompletely characterized. To address this, we collected 840 symptomatic melon samples from 12 prefectures in Xinjiang and employed RT-PCR with virus-specific primers for detection. Eight viruses were identified: zucchini yellow mosaic virus (ZYMV, 85.5%), watermelon mosaic virus (WMV, 81.2%), cucumber mosaic virus (CMV, 80.1%), cucurbit aphid-borne yellows virus (CABYV, 57.9%), papaya ringspot virus (PRSV, 42.3%), cucumber green mottle mosaic virus (CGMMV, 25.5%), cucurbit chlorotic yellows virus (CCYV, 20.5%), and melon necrotic spot virus (MNSV, 11.1%). Virus composition exhibited pronounced spatial heterogeneity, with southern Xinjiang showing a broader spectrum of viruses and higher diversity of co-occurring infections compared to northern prefectures. Virus Mixed Infections (VMI) were widespread, with CMV, WMV, and ZYMV most frequently involved. Across the dataset, 90 distinct VMI patterns involving 2-8 viruses were documented, and the most common combinations tended to cluster geographically within individual prefectures or across adjacent prefectures. These patterns highlight the complex, region-specific structure of melon viromes and suggest that local climatic conditions, cropping intensity, and host availability drive both virus diversity and mixed-infection dynamics. Overall, this study provides a comprehensive baseline of melon virus occurrence in Xinjiang, emphasizing the spatially structured nature of viral communities and the prevalence of mixed infections. These insights are critical for informing targeted disease management strategies, including region-specific surveillance, vector control, and the development of multi-virus-resistant melon cultivars.