Molecular characterization of a distinct begomovirus infecting tobacco in Yunnan, China

Virus isolate Y3V, obtained from tobacco showing leaf curl symptoms in Yunn an, China, had particles with the size and morphology typical of geminiviru ses. In reactions with a set of monoclonal antibodies raised against begomo viruses, Y3V was readily differentiated from two previously studied Chinese Begomovirus isolates. The complete nucleotide sequence of a DNAA-like mole cule of Y3V was determined; it comprises 2744 nucleotides and has a typical Begomovirus genome organization. When compared with the DNA-A sequences of other begomoviruses, the total DNA-A of Y3V was most closely related to th at of Ageratum yellow vein virus (AYVV) (85% sequence identity), but the Y3 V intergenic region differed greatly from those of the other sequences (max imum 70% identity). In contrast, the deduced coat protein of Y3V is most li ke that of Tomato yellow leaf curl Thailand virus-[1] (TYLCTHV [1]) (92% am ino acid sequence identity). The molecular data show that the Yunnan isolat e of Tobacco leaf curl virus is a distinct Begomovirus species, for which t he name Tobacco leaf curl Yunnan virus (TLCYnV) is proposed.