Abstract
Tobacco mosaic tobamovirus (TMV) is one of the most destructive virus threatening worldwide tobacco production. Use of host resistance is the best method of control. The N-gene was introgressed into tobacco from Nicotiana glutinosa to confer hypersensitive resistance to TMV. Phenotypic selection of TMV resistant germplasm is expensive, slow and unreliable. Use of N-gene specific primers is efficient in selecting TMV resistant germplasm in marker-assisted breeding. This study aimed at assessing the utility of N-gene specific primers in flue cured and dark-fire cured tobacco breeding materials in Zimbabwe. Four specific primers namely N1/N2, AS1/AS2, E1/E2 and SD1/SD2 were used to detect the N-gene in flue cured and dark-fire cured tobacco. DNA was extracted from young leaves of tobacco plants and quantified by a spectrophotometer. Polymerase chain reaction (PCR) mix and amplifying conditions for the four specific primer pairs were optimized. Results show that out of the four sets of primers used, AS1/AS2 and SD1/SD2 did not produce expected band products, while N1/N2 and E1/E2 detected the N-gene in flue cured and dark-fire cured tobacco. Therefore, the use of N1/N2 and E1/E2 primers will be relatively cheap, effective and quick in the foreground selection of the N-gene.
Keywords: N-gene, specific primers, resistance, molecular markers, Nicotiana tabacum.
African Journal of Biotechnology Vol. 12(24), pp. 3783-3789