27 May 2010 11:00
Unit:
Wageningen University
Location:
Aula, building 362, Gen. Foulkesweg 1, Wageningen
Organisation:
Wageningen University
Promotor:
prof.dr.ir. E. Jacobsen (Plant Breeding (Genetical Variation and Reproduction))
Co Promotor:
Dr. F.A. Krens, Dr.ir. H.J. Schouten
Towards durable resistance to apple scab using genetic modification of susceptible, elite varieties with only resistance genes derived from apple itself.
Apple is an important fruit crop. Apple scab is an important fungal disease, caused by Venturia inaequalis. The reduction in yields can reach 70% and chemical control of this disease requires 80% of the chemical crop protectants used in apple cultivation. Introducing disease resistance to a susceptible plant through conventional crossing takes a lot of time with inevitable loss of quality. Alternatively, genetic modification, being faster and maintaining quality, can be employed. The genes required for this approach can be isolated from resistant apple varieties (cisgenes). One such source of genes is presented by the Vf gene cluster. Two genes, Vf1 and Vf2 believed to be involved in giving resistance against V. inaequalis, were checked thoroughly in this study. Apple transformants with eitherVf1 or Vf2 were developed through genetic modification. These apple transformants were checked for their performance in disease assays. It was found that Vf1 does not provide resistance. Vf2 is the only gene in this cluster which gives resistance against V. inaequalis fungus. Combining Vf2 with other apple-derived scab resistance genes opens up the way to make and cultivate durable, cisgenic apple varieties.