Characterization of vsiRNAs derived from Cymbidium Mosaic/Odontoglossum Ringspot Viruses in co-infected Phalaenopsis equestris
[Objective]Interactions between Phalaenopsis equestris and cymbidium mosaic virus(CymMV)and odontoglossum ringspot virus(ORSV)were studied to aid the effort in developing effective preventive and control means against the diseases caused by the pathogens.[Method]The coat protein(CP)genes of CymMV and ORSV were amplified using RT-PCR.Under an electron microscope,viral morphology and size of CymMV and ORSV particles in P.equestris cells were examined.Abundance,length,base preference and origin of virus-derived vsiRNAs were analyzed applying the small RNA deep sequencing technology.[Result]The amplifications of CP genes of CymMV and ORSV were specifically obtain by RT-PCR.The electron microscopy revealed the lengths of the rod-like CymMV to be approximate 300 nm,while the linear ORSV,500 nm.The small RNA deep sequencing yielded 7 563 892 CymMV-derived and 6 133 689 ORSV-derived vsiRNAs exhibiting the universality and specificity in abundance,length,base preference and sense strand distribution.[Conclusion]Co-infections of CymMV and ORSV on P.equestris were clearly demonstrated in this study.The vsiRNAs of CymMV and ORSV displayed characteristic patterns in abundance,length,base preferences and sense strand distribution.