Cuscuta spp. populations as potential reservoirs and vectors of four plant viruses

Members of the genus Cuscuta or dodders represent widely distributed holoparasitic flowering plants with large agricultural and ecological significance. Besides their direct negative impact on the growth and development of host plants, they are also regarded as putative vectors of various pathogens, including plant viruses. In the present study, a total of 36 populations, belonging to 4 Cuscuta species from Bulgaria were tested for the presence of 4 of the most damaging and widely distributed plant viruses. It was found that while a significant proportion of the populations of Cuscuta campestris , which is introduced in the country were positive for Tomato Yellow Leaf Curl Virus (19%) and Cucumber Mosaic Virus (30%), only a single population of the other 3 species (native to the country) was positive for both. No occurrence of Tobacco Mosaic Virus or Alfalfa Mosaic Virus was detected. Furthermore, the C. campestris was also shown to be effective in transmitting viral infection to host plants. Overall, the presented results suggest that the introduced parasitic plant species is a significant reservoir and vector for viral diseases, which represents a further concern about its agricultural impact.