Potential of marker-assisted selection for <i>Tobacco mosaic tobamovirus</i> resistance in tobacco breeding

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