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Lily symptomless virus (LSV) occurs frequently in many Lilium species worldwide and often causes developmental abnormalities such as a smaller flower and lower bulb yield. In this study, two moderate and efficient gel filtration chromatography (GFC) methods was compared, these two techniques were, respectively, based on Superdex-200 HR and Sephacryl S-1000 SF. The products purified by the two methods were then characterized by measurements with UV-spectrophotometer, reverse transcriptase (RT)-PCR, transmission electron microscope (TEM), polyacrylamide gel electrophoresis (PAGE), Western blotting and matrix assisted laser desorption-ionisation/time-of-flight mass spectrometry (MALDI-TOF-MS). The final yield of purified LSV by the Superdex-200 HR GFC was 9.4 mg from 50 g of fresh infected tissues of Lanzhou lily. However, from the same amount tissues, only 5.6 mg of LSV were obtained by using Sephacryl S-1000 SF GFC. The Superdex-200 HR method was thus shown to be more suitable for the purification of LSV than the Sephacryl S-1000 SF GFC. The Superdex-200 HR method does not require costly equipment for density centrifugation and ultracentrifugation. Furthermore, it can provide an economical and efficient way to obtain purified products for the preparation of antibodies for serological diagnosis or LSV infection and related investigations.

Molecular detection of Yam mosaic virus (YMV), the most important potyvirus for yam plants (Dioscorea spp.) has been limited by its high genetic diversity. According to recent phylogenetic data, suitable molecular tools were developed for detection and genotyping. A reliable and rapid molecular test is described using single-tube immunocapture (IC)-RT-PCR combining the use of a monoclonal antibody able to recognise all YMV serotypes and primers designed to take into account the whole variability of YMV. Phylogenetic data were then used to develop an uncoupled IC-RT-PCR procedure adapted to the genotyping of the three major phylogenetic groups and the two recombinants implicated in the YMV epidemics in the Caribbean and French Guiana. A third exploitation of phylogenetic data was carried out with the development of a typing test based on the analysis of short nucleotide sequences. The direct sequencing of a 450 nts fragment constituted a reliable complementary typing tool as the resulting information was quite similar to that obtained with sequences of the complete coat protein gene. The approach, consisting in a robust study of YMV variability followed by the use of phylogenetic data to develop reliable detection and genotyping tools, offers new perspectives for powerful molecular epidemiological studies.