The interactions between tobacco vein distorting virus and tobacco bushy top disease-associated RNA
Tobacco bushy top disease is the only plant viral disease caused by the umbravirus/luteovirus complex so far in China, resulting in significant economic losses in tobacco production in the Yunnan Province of China. Tobacco bushy top disease complex is the most complicated umbravirus/luteovirus complex discovered so far. The coat proteins of the virions of tobacco bushy top disease complex are encoded by tobacco vein distorting virus (TVDV) only, while there are five distinct viral RNA components being encapsidated. The agroclones of TVDV and tobacco bushy top disease-associated RNA (TBTDaRNA) were obtained and used as a reverse genetics platform to investigate the interactions between these two viral components through agroinfection. The agroclone of TBTDaRNA is the first agroclone of Polerovirus-associated RNA built to date. TVDV alone could infect Nicotiana benthamiana systemically via agroinoculation without prominent symptoms. While TBTDaRNA itself could not infect N. benthamiana systemically, the plants developed intensive disease symptoms when agroinoculated with TBTDaRNA and TVDV simultaneously, and the two viral components could move systemically in the plants. The results indicated that TVDV could facilitate the systemic movement of TBTDaRNA in plants, and TBTDaRNA helped TVDV in boosting the development of disease symptoms in N. benthamiana.