1Institute of Plant Protection，Xinjiang Academy of Agricultural Sciences，Key Laboratory of Integrated Pest Management in China North-western Oasis，Ministry of Agriculture and Rural Affairs，Urumqi 830091，Xinjiang，China；2Altay Vegetable Basket Engineering Program Office，Altay 836500，Xinjiang，China
Abstract：In 2019，47 melon leaf samples with typical symptoms of Cucurbit aphid-borne yellows virus（CABYV）were collected from 7 counties/cities in Southern Xinjiang．This study conducted CABYV detection by RT-PCR．One representative sample was selected from each county/city．This study also carried out clone sequencing on specific fragment，and analyzed the nucleotide diversity，protein sequence，and phylogeny．Results showed that 28 leaf samples（Detection ratio was 59.57%）presented CABYV positive．The detection ratioes of Bachu，Akesu，Shache，Jiashi，Shule，Shufu and Luopu were 80.00%，28.57%，83.33%，60.00 %，37.50%，71.42% and 66.67%，respectively．Clone sequencing obtained 707 bp nucleic acid sequence，and the nucleotide diversity value was between 0.012-0.018．All sequences had 2 ORFs（ORF1 and ORF2）．ORF1 encoded 199 amino acid of coat protein（CP）．The sequence similarity of each county/ city was 99.07%．ORF2 encoded 191 amino acid of movement protein（MP）．The sequence similarity of each county/city was 98.80%．The phylogenetic trees constructed on CP and MP sequences base indicated that all sequences obtained from each county/city were all clustered with the Asian branch．Those results demonstrated that CABYV occured commonly in the main melon production areas in Southern Xinjiang，and the nucleotide variation in different regions was very low．CABYV in these regions had close genetic relationship with isolates from China and Japan，while having a farther relationship with European and Taiwan isolates．
