Molecular breeding for virus resistant potato plants

Abstract

To engineer resistance against potato virus X (PVX), the viral coat protein (CP) gene has been introduced into two potato cultivars. Stable expression of the gene in transgenic clones throughout the growing season has been obtained and resulted in considerably increased virus resistance. With varying frequencies depending on the original cultivar used, true-to-type PVX resistant transgenic clones have been obtained. Since deviant light sprout characteristics were invariably associated with aberrations in plant phenotype, they can be used in procedures to early screen for deviations. Furthermore, it has been possible to unequivocally discriminate between the original untransformed and independent transgenic cultivars. Although no relation has been found between the presence, if any, of the CP of potato virus Y (PVY) or potato leafroll virus (PLRV) in CP gene transgenic potato, appreciable levels of resistance to these viruses has been obtained. This suggests that the mechanism by which a viral CP gene in the potato genome evokes resistance, differs amongst various viruses.

Advances and prospects in potato virology with special reference to virus resistance

“…The main effects are to make plants more resistant to infection (Nelson et al, 1987), and to prevent or delay systemic invasion of those plants that become infected. Potato genotypes resistant both to PVY and PVX have been produced in this way (Lawson et al, 1990); those with PVX resistance alone are described in this symposium by Huisman et al (1992). Plants with coat protein-mediated resistance to PLRV have also been produced.…”