Abstract:

Cucurbit aphid-borne yellows virus（CABYV）causes yellowing symptom in cucurbit crops and distributes widely in China. Sixty-three samples exhibiting yellowing symptom were collected from Shanshan of Xinjiang，Guazhou of Gansu，and Tongxu of Henan in China. Among them，36 were positive to CABYV detected by RT-PCR. A 1.4 kb fragment consisting of partial RNA-dependent RNA polymerase（RdRp），intergenic NCR and complete coat protein（CP）gene was amplified by RT-PCR from 25 positive samples. Blast analysis showed that the fragments have high similarities of 93.2%–100% with other CABYV isolates from GenBank. The nucleotide sequence identities of CP gene were 99.2%–100% for Shanshan isolates，98.2%–100% for Guazhou isolates，98.8%–99.8% for Tongxu isolates. Phylogenetic trees based on partial RdRp，NCR and CP genes showed that the 25 isolates had a very close relationship with other isolates from China and other countries neighboring China including Thailand，South Korea etc， but a distant relationship with European isolates，suggesting that CABYV variation appeared to be associated with its geographical distribution.

Key words: cucurbit, Cucurbit aphid-borne yellows virus, molecular diversity, sequence alignment