TABLE CONTENTS

The Potential of Resistance Gene Analogs (RGAs) of Wild Beet (Beta
procumbens) for Breeding of Rapeseed (Brassica napus) Cyst Nematode
Resistance
Guixian, T. (1), K. Knecht (2), Y. Qin (1), W.J. Zhou (1) & D. Cai (2)
(1) Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, 310029, PR
China; (2) Department of Molecular Phytopathology, Christian-Albrechts-University of Kiel, Hermann
Rodewald Str. 9, D-24118 Kiel, Germany
Plant-parasitic nematodes cause >$100 billion annual losses to world agriculture, of which
cyst nematodes and root-knot nematodes contribute over 80%. Oilseed rape (Brassica napus)
is highly susceptible to the beet cyst nematode Heterodera schachtii (BCN) and no resistance
in Brassica germplasm is available. To convert oilseed rape from a host into a resistant trap
crop for BCN, attempts had been made worldwide to transfer resistance e.g. from radish
(Raphanus sativus) and white mustard (Sinapis alba) resulting in resistant monosomic
addition lines, but breeding BCN resistant oilseed rape still remains a great challenge. Here,
we report the transfer of two BCN resistance genes isolated from wild beet (B. procumbents)
into the oilseed rape genome and functional analysis of transgenes in respect to their
conferring BCN resistance in oilseed rape. Transgenic plants expressing the gene Hs1 pro-1 and
a RGA cZR-3 respectively were produced by Agrobacterium-mediated transformation.
Pyramiding of two genes in the oilseed rape genome was realized by crossing of respective
transgenic plants. Nematode resistance tests with transgenic plants expressing the trangenes
were performed in vitro and in vivo as well. As a result, transgenic plants, independent of the
transgenes, all showed significant reduction in the mean number of developed cysts per plant,
compared to control plants. Strikingly, a clearly pyramiding effect of two genes expressing in
oilseed rape on the inhibition of nematode development was given. More than 70% of
transgenic plants expressing the double genes had less than 2 cysts, compared with 48% and
50% for plants expressing cZR3 and Hs1 pro-1 , respectively, and 2.5% for control plants. These
results strongly demonstrate the potential of resistance genes and RGAs from wild beet for
breeding BCN resistance in oilseed rape. A possible mechanism of the gene pyramiding
effect is discussed.
Acknowledgements: The project was sponsored by DAAD short-time stay in Germany, DFG SFB617-
A19 and the Scientific Research Foundation for the Returned Overseas Chinese Scholars (SRF for
ROC), Zhejiang province, PR China.
5 th International Congress of Nematology, 2008 16