RNA-2 OF TOBACCO RATTLE VIRUS ENCODES THE DETERMINANTS OF TRANSMISSIBILITY BY TRICHODORID VECTOR NEMATODES

Pseudorecombinant isolates produced from an efficiently transmitted an d a non-transmitted isolate of tobacco rattle tobravirus were tested f or their transmissibility by trichodorid vector nematodes. Isolates wi th RNA-2 originating from the non-transmissible isolate were not trans mitted by the vector, whereas isolates with RNA-2 originating from the efficiently transmitted isolate were transmitted efficiently. It is t herefore concluded that the factor determining vector transmissibility is located on the RNA-2 genome segment of TRV. Because the serologica l properties of the isolates also correlate with transmissibility, it is likely that the virus particle protein is involved in the transmiss ion process.