Complete nucleotide sequence of a novel monopartite begomovirus infecting tobacco in China

Two full-length monopartite begomovirus sequences were obtained from tobacco plants exhibiting severe yellowing, leaf curling, and crumpling symptoms in Guizhou province of China. Both full-length sequences contain 2,746 nucleotides (nt) and share 100% nucleotide identity with each other. Sequence comparison revealed that the virus shares the highest nucleotide sequence similarity (88.3% identity) with tomato leaf curl Guangxi virus (ToLCGXV; species Begomovirus solanumguangxiense). According to the current species demarcation criteria for the genus Begomovirus established by the International Committee on Taxonomy of Viruses (ICTV), the virus represents a novel species in the genus Begomovirus, for which we propose the name tobacco yellow leaf curl virus (TbYLCV; proposed species name Begomovirus nicotianaflavi). Phylogenetic analysis revealed that TbYLCV clusters with ageratum yellow vein China virus (AYVCNV) and ageratum yellow vein virus (AYVV) in a small monophyletic branch, indicating their close genetic relatedness. The identification of this novel begomovirus further enriches the species diversity of begomoviruses infecting tobacco and provides new molecular evidence for the surveillance and control of tobacco leaf curl disease.