1Division of Biochemistry, Indian Agricultural Research Institute, New Delhi 110 012, India
2Plant Virology Unit, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi 110 012, India
*Corresponding author. E-mail: shellypraveen@hotmail.com
†Part of M.Sc. thesis submitted by Ginny to Postgraduate School, IARI, New Delhi 110 012.
A chimeric transgene composed of two different viral gene segments, was employed to confer multiple virus resistance in transformed tomato through homology-dependent gene silencing. Two important viruses of tomato, Cucumber mosaic virus (CMV) and Tomato leaf curl virus (ToLCV) were targeted. Comparison of 657 nucleotide coat protein (CP) region of CMV isolate (CMV-B) with those of five other CMV-Indian isolates showed more than 95% identity both at the nucleotide as well as amino acid level. Our previous studies showed the presence of conserved domain in the replicase gene of ToLCV comprising of 319 nts at 3’ of the gene. With this in view, gene encoding full-length transcript of CP of CMV-B was fused with the conserved domain of replicase gene of ToLCV. This is a first attempt of the transcriptional fusion of viral gene segments derived from a DNA virus (ToLCV) and a RNA virus (CMV). The chimeric gene construct was transformed in L. esculentum for multiple virus resistance, which is expected to work through homology - dependent gene silencing.
chimeric gene, homology-dependent gene silencing, virus resistance, CMV, ToLCV
