The presence of pathogenic plant viruses was found in an analysed inflow sample of the wastewater treatment plant Domžale - Kamnik. We focused on detecting the Cucumber green mottle mosaic virus (CGMMV) and the Pepper mild mottle virus (PMMoV). The main purpose of the study was to discover whether the viruses CGMMV and PMMoV from the inflow sample, after having been concentrated with CIM monolithic chromatography, were infective. The CIM monolithic chromatography increased the concentration of viruses for two orders of magnitude. Viruses were detected using the method of reverse transcription real time polymerase chain reaction (RT-qPCR), while infectivity was tested with mechanical inoculation of host plants. Infectivity of the CGMMV and the PMMoV viruses from the inflow sample, concentrated with CIM monolithic chromatography, was not proven. However, we did see intact virus particles in the inflow sample using electron microscopy. Despite the high concentrations detected with molecular methods and intact virus particles seen with electron microscope, the viruses exposed to conditions from the inflow sample did not maintain a sufficient concentration of intact virus particles to infect host plants with mechanical inoculation. Additional controls of inoculation excluded NaCl and the substances from the inflow sample which were concentrated along with the virus particles as reasons for the loss of infectivity. Before the sampling and concentration step, viruses from the inflow sample are already exposed to different substances that can influence their infectivity. For future research we suggest the use of pre-column before concentration step and immediate inoculation of test plants without freezing the elution fractions.
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