Molecular Characterization of Two Isolates of Wild Tomato Mosaic Virus and Chilli Veinal Mottle Virus Co-infecting Chilli Pepper in China

The present study reports observation of a field chilli pepper disease consisting of a co-infection with two potyviruses: Wild tomato mosaic virus Dehong isolate (WTMV-Dh) and Chili veinal mottle virus Dehong isolate (ChiVMV-Dh). We obtained the complete genome sequences of these two viruses by NGS sequencing. The WTMV-Dh is 9,598 nucleotides (nt) in length and encodes a complete polyprotein of 3,075 amino acids (aa). The polyprotein of WTMV-Dh shares 76.1–82.6% nt and 85.3–89.5% aa identities with the other three WTMV isolates reported previously. The ChiVMV-Dh is 9688 nt in length and encodes a complete polyprotein with 3, 089 aa. The polyprotein of ChiVMV-Dh shares 80.8–92.2% nt and 85.3–95.6% aa identities with the other ChiVMV isolates reported previously. Following phylogenetic analysis based on the polyprotein sequences of other potyviruses, WTMV-Dh clustered with the Vietnam strain WTMV-Laichau while ChiVMV-Dh clustered with several ChiVMV Sichuan isolates. Evaluation of the recombination events within the WTMV and ChiVMV subgroups indicated that some putative recombination events occurred in critical regions. These regions include the N-terminal of HC-Pro and P1 region of WTMV-Dh, CP and the P3 to CI region of ChiVMV-Dh, which may be new evidence of adaptive evolution of potyviruses.