Papaya Leaf Curl Guangdong Virus and Ageratum Yellow Vein Virus Associated with Leaf Curl Disease of Tobacco in China

Two samples ( YC 7, YC 27) of N icotiana tabacum showing leaf curling, vein swelling and enations on undersides of leaves were collected in the F ujian P rovince of C hina in 2007. Virus isolates YC 7‐1 and YC 7‐2 (associated with betasatellite, YC 7‐2β) were detected in both samples. The complete DNA ‐ A sequence of YC 7‐1 ( FJ 869907) comprised 2741 nucleotides (nt). The complete DNA ‐ A ( FJ 869908) and betasatellite ( FJ 869909) sequence of YC 7‐2 consisted of 2754 and 1344 nt, respectively. YC 7‐1 had the highest nucleotide sequence identity (97.3%) with P apaya leaf curl G uangdong virus ( P a LC u G u V ‐[ CN :Gd2:02], AJ 558122). YC 7‐2 had the highest sequence identity (90.1%) with A geratum yellow vein virus ( AYVV ‐ TW [ TW : T ai:99], AF 307861) and its betasatellite (96.5%) with Ageratum yellow vein betasatellite ( AYVB ‐[ TW : CH u:02], AJ 542495). These indicate that YC 7‐1 and YC 7‐2 are isolates of P a LC u G u V and AYVV , respectively. Symptoms including leaf curling, vein swelling and enations on undersides of leaves were observed in N . tabacum and N . glutinosa when infected by whiteflies with sample YC 7 as the viral source under greenhouse conditions. PCR results showed that these infected plants contained both YC 7‐1 and YC 7‐2/ YC 7‐2β. To our knowledge, this is the first report of P a LC u G u V and AYVV / AYVB co‐infecting N . tabacum in C hina.