Recombination and Mutation in a New HP-PRRSV Strain (SD2020) from China

Figures

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  Figure 1. Pathological changes in infected lung tissue. (A) Gross lesions (B,C) Microscopic lesions (D) Antigens were detected by immunohistochemistry using monoclonal antibodies against N protein of PRRSV. “” indicates hemorrhage, “” indicates edema, “” indicates transparent membrane, “” indicates lymphocytic infiltration, “” indicates inflammatory exudation, “” indicates positive signal.

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  Figure 2. Virus isolation and identification. (A) SD2020 empty spot assay for isolation and purification, red arrows point to virus empty spots. (B) Isolation of SD2020 in Marc-145 cells and the result of RT−PCR assay. Lane 1 indicates the negative control, lane 2 indicates the positive control of JXA1, lane 3 indicates the result of SD2020 RT−PCR, and lane 4 indicates the DNA marker (DL 2000). (C) Growth kinetic curve of SD2020.

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  Figure 3. Recombination analyses on SD2020 genome. (A) Recombination analysis was conducted and a similarity map was generated by Simplot 3.5.1 software with window size of 200 bp and step size of 20 bp. SD2020 as query sequence, was used in similarity plot analysis. (B) Schematic diagram of SD2020 PRRSV genomes. (C) Recombination regions were shown with segments of different colors and the four recombination breakpoints were detected by RDP v4.1016. Red segments represent the sequence of VR-2332 strain. Blue segment represents the sequence of JXA1-P80 strain. Green segment represents the sequence of JXA1 strain. (D) Individual phylogenies reconstructed from non-recombinant fragments identified by RDP v4.1016, with the JXA1-like strain labelled with a blue background and the VR2332 strain labelled with a red background. The phylogenetic tree was constructed by using the neighbor-joining method with 1000 bootstrap replicates in the PHYLIP 3.65 software package.