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.