conference schedule and program with abstracts - Horticulture ...

O-7
Sequencing of the phylloxera resistance locus Rdv1 of cultivar ‘Börner’
L. Hausmann*, R. Eibach, E. Zyprian, R. Töpfer
Federal Research Centre for Cultivated Plants, Julius Kuehn Institute, Institute for Grapevine
Breeding, Geilweilerhof, Siebeldingen, Germany
*Corresponding author: ludger.hausmann@jki.bund.de
In the middle of the 19 th century phylloxera (Daktulosphaira vitifoliae Fitch) was introduced
from North America to Europe and dramatically damaged the viticulture. The insect attacks the
root tips and older roots of grapevine leading to gall-like deformed structures called nodosities
and tuberosities, respectively. The former gall type results in slight damage but the latter type
leads together with secondary fungal infections to the dieback of the whole vine. To overcome
the problem phylloxera-tolerant rootstocks were developed from American wild Vitis species
onto which scions of European grapevine cultivars were grafted. Nevertheless most rootstock
cultivars currently used show nodositiy symptoms after phylloxera infection. In contrast,
rootstock cultivar ‘Börner’, an interspecific cross of V. riparia Gm 183 and V. cinerea Arnold, is
phylloxera-resistant as it shows neither tuberosity nor nodosity symptoms. To characterize the
genetic basis of the ‘Börner’ phylloxera resistance a segregating population derived from the
cross V3125 (Schiava grossa x Riesling) x ‘Börner’ was used to establish a genetic map. The
artificially infected progeny was phenotyped concerning nodosities and a single quantitative trait
locus, Rdv1, could be localized on chromosome 13. Fine mapping was performed developing
synteny-derived STS markers deduced from the PN40024 reference sequence. Further resolution
was obtained with a local map based on a set of recombinant vines restricting the Rdv1 locus
down to a size of about 350 kb related to the reference sequence. From a pooled BAC library
clones were isolated covering the entire region and subsequently sequenced. A small RGA
cluster is located in the Rdv1 locus as it is the case in the corresponding region of the reference
sequence. However, size and structural arrangement of the repetitive resistance genes differs
clearly giving reason to identify candidate genes for phylloxera resistance within this core
region.
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