Abstract: Thirty-six tomato samples with severe stunting，yellowing and leaf-curling symptoms were collected in Panzhihua，Sichuan Province. Fragments of about 500 bp were amplified from all samples using the begomoviruses degenerate primers PA and PB. The complete genome sequence analysis showed that the diseased tomato samples were infected by Papaya leaf curl China virus（PaLCuCNV）and Tomato yellow leaf curl China virus（TYLCCNV）and 97.2% samples were infected with both viruses. Sequence analysis showed that PaLCuCNV had the highest sequence identity（99.1%）with PaLCuCNV-[HeNZMI] isolated from tomato in Henan，and TYLCCNV shared the highest sequence identity（97.9%）with TYLCCNV-[Y295] isolated from tobacco in Yuanmou，Yunnan. In addition，all isolates were found to be associated with DNA β molecules. Nine complete DNA β sequences were determined and showed  the highest sequence identity with DNA β of TYLCCNV（TYLCCNB-[SC65]），being ranged from 87.7% to 94.5%. This is the first report that tomato yellow leaf curl disease was caused by the co-infection of PaLCuCNV and TYLCCNV/TYLCCNB.

Key words: tomato, Papaya leaf curl China virus, Tomato yellow leaf curl China virus, full length DNA sequences, co-infection, satellite DNA β