Abstract:
In an effort to identify genetic markers for virus infection of plants, the model plant Arabidopsis thaliana was used to identify small RNAs that show generic accumulation changes in response to infection with five distinct plant viruses. The DNA virus Cauliflower mosaic virus, a negative stranded RNA virus Tomato spotted wilt virus and three unrelated positive stranded RNA viruses, Tobacco mosaic virus, Turnip mosaic virus, and Turnip yellow mosaic virus, were used to represent the wide diversity of plant viruses. Leaf tissue from plants infected with each of the five viruses and mock-inoculated plants was used for RNA isolation. RNA sequencing and radioactive northern blot hybridisation were used to identify small RNA accumulation changes over a 21-day time course. RNA sequencing identified one small RNA, miR156, that showed a significant negative fold change in all of the virus-inoculated plants compared to mock-inoculated plants. The findings from sequencing were not confirmed by northern blot analysis due to degradation of RNA in the process of hybridisation. The generic negative change in accumulation of miR156 upon virus infection identified in this study can be further investigated in other virus infections and in other plant species to determine whether it might be used as the basis of a tool to identify virus-infected plants.