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.

By combining next-generation sequencing (NGS), reverse transcription polymerase chain reaction (RT-PCR), and rapid amplification of cDNA ends (RACE) PCR, we sequenced from adult bean flower thrips (Megalurothrips usitatus) the near-complete genome of a previously undescribed virus (related to Anopheline-associated C virus), which we named “Megalurothrips usitatus associated virus 1” (MUaV1). The viral genome comprises two linear, single-stranded, positive-sense RNA segments, designated RNA1 (3658 nt) and RNA2 (2041 nt), which shared 35.75% and 23.74% nucleotide identity with Anopheline-associated C virus (YP_009011225.1) and chronic bee paralysis virus (ASM62179.1), respectively. According to phylogenetic analysis, MUaV1 shares the closest evolutionary relationship with Anopheline-associated C virus, followed by chronic bee paralysis virus. A clear predominance of 22 nt vsiRNAs, characteristic of Dicer-mediated siRNA processing in insects, was observed, demonstrating that MUaV1 is capable of infecting the bean flower thrips and activating its antiviral RNAi response. Our study provides the first characterization of this virus in the bean flower thrips, enhancing our understanding of the bean flower thrips virome.