Characterization of New Species of Begomoviruses and Their Satellites, Infecting Eclipta prostrata and Rosa chinensis
Master of Science
Biochemistry & Biotechnology
Date of Defense
Wendy M. Olivas, PhD
Satellites associated with begomoviruses are causing huge crop losses throughout the World, particularly in South Asia. Although much is known about the diversity of begomoviruses and their satellites infecting major crops such as cotton, tomato and chilies, other hosts such as weeds and ornamental plants are not well studied. During 2006-2007, ornamental rose plants (Rosa chinensis) were found with highly stunted growth and upward leaf curling in Faisalabad, Pakistan. Another commonly growing weed (Eclipta prostrata) showing vein yellowing was also analyzed for begomovirus infection. By using the rolling circle amplification method (which does not require prior sequence information for amplifying circular single stranded DNA molecules) followed by complete nucleotide sequencing, we discovered two new begomoviruses and their satellites infecting these hosts. In line with taxonomic conventions for begomovirus species, new names Rose leaf curl virus (RoLCuV) and Eclipta yellow vein virus (EcYVV) are proposed. Phylogenetic analysis based on their complete nucleotide sequences suggested that both viruses could be clustered with already identified monopartite begomoviruses from the region. EcYVV is closely related to Cotton leaf curl Bangalore virus (84%) and RoLCuV shows close identity (83%) with Tomato leaf curl Pakistan virus. One betasatellite isolated from these hosts showed less than 78% identity with other known betasatellites and can therefore be considered as a member of a new species. The second betasatellite isolated with EcYVV was found to be an isolate of the species Kenaf leaf curl betasatellite. The infectious molecules for each of the virus/satellite were prepared and inoculated through Agrobacterium to model host Nicotiana benthamiana plants, which induced severe vein yellowing and leaf curling. We conducted further experiments to understand the flexibility of betasatellite trans-replication in the presence of non-cognate begomoviruses. The betasatellites identified in this study are promiscuous in their ability to be trans-replicated by a non-cognate, already known bipartite virus; Tomato leaf curl New Delhi virus. The potential threat and replication flexibility of replication of the different molecules in the begomovirus disease complexes studied here is discussed.
Khatri, Sandeep Manohar, "Characterization of New Species of Begomoviruses and Their Satellites, Infecting Eclipta prostrata and Rosa chinensis" (2009). Theses. 1.