Wheat dwarf virus (WDV) has been one of the most common viruses on cereal crops in Poland in the last years. This single stranded DNA virus is transmitted by the leafhopper spec, Psammotettix alienus (Dahlb.) in a persistent manner. It induces yellowing and streaking of leaves, dwarfing or even death of infected plants. The presence of barley- and wheat-specific forms of WDV (WDV-B and WDV-W) and their vector were previously reported in the country, however the literature data did not include any information on the infectivity of the vector in Poland. A duplex polymerase chain reaction (PCR) procedure was developed and optimized for simultaneous detection and differentiation of both forms in the vector. Two sets of primers amplify 734 bp and 483 bp specific fragments for WDV-W and WDV-B, respectively. The results were verified by a sequencing method. The studies were carried out on insect samples collected in autumn from four different locations in Greater Poland. The results confirmed the presence of WDV-W in the tested samples. They also suggested the concomitant of both forms of the virus in the vector. Additional studies to determine virus-vector relationships should be undertaken.
Water samples were collected from irrigation ditches and drainage canals surrounding fields in southern Greater Poland. Initially, the samples were subjected to low and highspeed centrifugation and obtained pellets were used to perform biological assays. Viral identification involved biological, electron microscopic as well as molecular methods. The occurrence of Tobacco mosaic virus (TMV) and Tomato mosaic virus (ToMV) was demonstrated in 12 of the 17 examined water sources. The molecular analysis results showed TMV and ToMV co-infections in the analysed water samples. To our knowledge, this is the first report of tobamoviruses being found in environmental water in Poland.
Plant viruses create many changes in the morphology of the plant cell once the infection process has begun. This paper describes and compares the ultrastructural changes induced in maize cells by two isolates of Maize dwarfmosaic virus (MDMV), Spanish (MDMV-Sp) and Polish (MDMV-P), and one isolate of Sugarcane mosaic virus (SCMV) at 10 and 42 days post-inoculation: the concentration and arrangement of virus particles, inclusion bodies associated with infection, and other cytological alterations. The most important difference between maize cells infected with MDMV isolates and with SCMV-P1 was in the form of cytoplasmic cylindrical inclusions. In cells infected with MDMV only typical inclusions such as pinwheels and scrolls were observed, but laminar aggregates were also present in SCMV-infected cells. No virus particles were found in plant cell organelles. Specific virion arrangements occurred in cells infected with MDMV-Sp and SCMV. The most interesting new finding was of specific amorphous inclusions in the cytoplasm of MDMV-Sp-infected cells, which clearly differentiated the two MDMV isolates studied.