Articles
DEVELOPMENT OF CISGENIC APPLES WITH DURABLE RESISTANCE TO APPLE SCAB
Article number
839_53
Pages
403 – 406
Language
English
Abstract
Most of the apple (Malus × domestica) growers are facing serious disease problems with apple scab which is caused by the fungus Venturia inaequalis. Developing a resistant variety in apple through classical breeding is very slow and inefficient.
So, we aim at improving existing apple varieties through a new concept called cisgenesis which saves time and effort compared to classical breeding. Malus floribunda proved to be a good source of natural scab resistance genes.
The genes HcrVf1 and HcrVf2, consisting of promoter, coding and terminator sequences in their natural configuration, were isolated from Malus floribunda and cloned into the binary vector pMF1. Apple cv. Gala was transformed with pMF1 containing HcrVf1 and HcrVf2, individually or in combination. pMF1 can be used to obtain marker-free plants by recombinase-based excision of a fragment carrying undesired gene sequences, such as antibiotic-selection marker genes, leaving behind only the gene(s)-of-interest and one recombination site.
Using this vector it is therefore possible to stack several genes by retransformation using the same selection procedure.
In order to obtain durable resistance, we have the intention to combine different resistance genes from Malus either by stacking them one by one or by introducing them all together in one T-DNA. Performance of all different types of cisgenic plants will be evaluated by monitoring scab resistance levels phenotypically and by determining gene expression profiles through quantitative RT-PCR.
So, we aim at improving existing apple varieties through a new concept called cisgenesis which saves time and effort compared to classical breeding. Malus floribunda proved to be a good source of natural scab resistance genes.
The genes HcrVf1 and HcrVf2, consisting of promoter, coding and terminator sequences in their natural configuration, were isolated from Malus floribunda and cloned into the binary vector pMF1. Apple cv. Gala was transformed with pMF1 containing HcrVf1 and HcrVf2, individually or in combination. pMF1 can be used to obtain marker-free plants by recombinase-based excision of a fragment carrying undesired gene sequences, such as antibiotic-selection marker genes, leaving behind only the gene(s)-of-interest and one recombination site.
Using this vector it is therefore possible to stack several genes by retransformation using the same selection procedure.
In order to obtain durable resistance, we have the intention to combine different resistance genes from Malus either by stacking them one by one or by introducing them all together in one T-DNA. Performance of all different types of cisgenic plants will be evaluated by monitoring scab resistance levels phenotypically and by determining gene expression profiles through quantitative RT-PCR.
Authors
S.G. Joshi, J.M. Soriano, A. Kortstee, J.G. Schaart, F.A. Krens, E. Jacobsen, H.J. Schouten
Keywords
Malus × domestica, Venturia inaequalis, marker-free plants, cisgenesis, gene stacking
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