Emerging tospoviruses cause significant yield losses and quality reduction in vegetables, ornamentals, and legumes throughout the world. So far, eight tospoviruses were reported in China. Tomato fruits displaying necrotic and concentric ringspot symptoms were found in Guizhou province of southwest China. ELISA experiments showed that crude saps of the diseased tomato fruit samples reacted with antiserum against Tomato zonate spot virus (TZSV). Electron microscopy detected presence of quasi-spherical, enveloped particles of 80–100 nm in such saps. The putative virus isolate was designated 2009-GZT. Mechanical back-inoculation showed that 2009-GZT could infect systemically some solanaceous crop and non-crop plants including Capiscum annuum, Datura stramonium, Nicotiana benthamiana, N. rustica, N. tabacum and Solanum lycopersicum. The 3012 nt full-length sequence of 2009-GZT S RNA shared 68.2% nt identity with that of Calla lily chlorotic spot virus (CCSV), the highest among all compared viruses. This RNA was predicted to encode a non-structural protein (NSs) (459 aa, 51.7 kDa) and a nucleocapsid protein (N) (278 aa, 30.3 kDa). The N protein shared 85.8% amino acid identity with that of CCSV. The NSs protein shared 82.7% amino acid identity with that of Tomato zonate spot virus(TZSV). Our results indicate that the isolate 2009-GZT is a new species of Tospovirus, which is named Tomato necrotic spot virus (TNSV). This finding suggests that a detailed survey in China is warranted to further understand the occurrence and distribution of tospoviruses.

The coat protein (CP) is an important structural protein that plays many functional roles during the viral cycle. In this study, the CP of pepper mild mottle virus (PMMoV) was genetically fused to GFP using the foot-and-mouth disease virus peptide 2A linker peptide and the construct (PMMoV-GFP^2A) was shown to be infectious. The systemic spread of the virus was monitored by its fluorescence in infected plants. Electron microscopy and immunocolloidal gold labelling confirmed that PMMoV-GFP^2A forms rod-shaped particles on which GFP is displayed. Studies of tissue ultrastructure and virion self-assembly confirmed that PMMoV-GFP^2A could be used to monitor the real-time dynamic changes of CP location during virus infection. Aggregations of GFP-tagged virions appeared as fluorescent plaques in confocal laser microscopy. Altogether, PMMoV-GFP^2A is a useful tool for studying the spatial and temporal changes of PMMoV CP during viral infection.

The genus Begomovirus constitutes a group of devastating plant viruses causing significant economic losses in the production of agricultural crops. In the present study, conducted in Yunnan province, China, a novel monopartite begomovirus was identified from Bidens pilosa, Crassocephalum crepidioides, tomato, pepper, and common bean, showing severe disease symptoms. The complete genome of the virus shows the typical organization of monopartite begomoviruses and shares the highest nucleotide sequence identity (88.73–88.95%) with crassocephalum yellow vein virus (CraYVV). According to the species criteria of the genus Begomovirus, this virus is a novel Begomovirus species, which has since been named “bidens pilosa leaf crumple virus (BpLCrV)”. Recombination analysis revealed that the novel species is a potential recombinant begomovirus derived from CraYVV and ageratum leaf curl virus (ALCuV), and phylogenetic analysis showed that BpLCrV was clustered with tomato yellow leaf curl Thailand virus (TYLCTHV) from China. We successfully developed a BpLCrV infectious clone. Agrobacterium-mediated inoculation of the BpLCrV infectious clone could effectively infect Nicotiana benthamiana, Nicotiana glutinosa, and Datura stramonium and cause disease symptoms. Thus, in this study, BpLCrV was, for the first time, identified and characterized as a novel begomovirus that infects not only weeds but also different important crops, potentially threatening agricultural production.

The genus Begomovirus constitute a group of devastating plant viruses causing significant economic losses in the production of agricultural crops. In the present study, a novel monopartite begomovirus was identified from Bidens Pilosa, Crassocephalum crepidioides, tomato, pepper and common bean showing severe disease symptoms in the Yunnan province of China. The complete genome of the virus shows the typical organization of monopartite reoviruses and shares the highest nucleotide sequence identity (88.73-88.95%) with crassocephalum yellow vein virus (CraYVV). According to the species criteria of the genus Begomovirus, this virus is a novel Begomovirus specie which was then named as “bidens pilosa leaf crumple virus (BpLCrV)”. Recombination analysis revealed that the novel species is a potential recombinant begomovirus derived from CraYVV and ageratum leaf curl virus (ALCuV), and phylogenetic analysis showed that BpLCrV was clustered with tomato yellow leaf curl Thailand virus (TYLCTHV) from China. We successfully developed the BpLCrV infectious clone. Agrobacterium-mediated inoculation of the BpLCrV infectious clone could effectively infect Nicotiana benthamiana, Nicotiana glutinosa and Datura stramonium and caused disease symptoms. Thus, in this study BpLCrV was firstly identified and characterized as a novel begomovirus, it infects not only weeds but also different important crops, with potential threat to agricultural production.