TABLE CONTENTS

Using natural Resistance Mechanisms for Plant Nematode Control
Knecht, K. (1), Y. Tian (2), J. Menkhaus (1), C. Jung (3), W. Yeh (1), T. Thurau (1) &
D. Cai (1)
(1) Department of Molecular Phytopathology, Christian-Albrechts-University Kiel, Hermann-Rodewald-Str. 9,
D-24118 Kiel, Germany; (2) Department of Life Science and Engineering, Harbin Institute of Technology,
China; (3) Plant Breeding Institute, Christian-Albrechts-University Kiel, Olshausenstr. 40, 24098 Kiel, Germany
Using natural resistance mechanisms for plant nematode control is a major focus of our
recent research. To identify genes involved in the Hs1 pro-1 mediated resistance response in
sugar beet, the cDNA-AFLP technique and ATH1 GeneChips were used for comparative
transcriptome analyses. A group of germin-like genes were identified whose expression is
specifically upregulated upon nematode infection in both resistant beet and Hs1 pro-1
transgenic Arabidopsis plants, suggesting their role in the Hs1 pro-1 -mediated nematode
resistance response. To investigate its potential for plant nematode control, we transformed
susceptible beet roots and Arabidopsis plants with the gene BvGLP-1 that shows homology to
oxalate oxidase-like genes and is functionally hypothesized to be involved in hydrogen
peroxide generation in plant cells. Two gene expression constructs were generated, of which
pAM-BvGLP-1 with 35S-promoter for a constitutive over-expression and pBin-BvGLP-1
with Hs1-promoter for a feeding-cell specific expression. Transgenic beet roots and
transgenic Arabidopsis plants were used for nematode infection experiments in which nontransgenic
beet roots and Arabidopsis plants served as controls. As a result, either transgenic
beet roots or Arabidopsis plants expressing the gene showed strong anti-nematode effect. The
regular development of nematode was inhibited resulting in significant reduction in the
number of developed female nematodes. The oxidase oxalate activity in transgenic plants was
determined by biochemical and histochemical assays showing a correlation with the antinematode
activity. However, a constitutive overexpression of the gene in plant cells resulted
in a lower regeneration rate and strong stagnation of the growth of transgenic beet roots and
Arabidopsis plants, which obviously suffered from an excessive hydrogen peroxide stress.
This result strongly suggests that an enhanced oxalate oxidase activity in nematode feedingcells
at the early developing stage represents a key mechanism of the Hs1 pro- 1 -mediated
nematode resistance, which can be effectively used for genetic engineering of plant nematode
resistance.
5 th International Congress of Nematology, 2008 132