TABLE CONTENTS

SESSION FORTY-EIGHT – EXPLOITING RNA INTERFERENCE IN
PLANTS AND NEMATODES
CONVENORS: CARLA DE GIORGI & ROSANE CURTIS
Host Delivered RNAi: An Effective Strategy to Control Plant Parasitic
Nematodes
Fairbairn, D.J., A.S. Cavallaro, M. Bernard, J. Mahalinga-Iyer, M.W. Graham
& J.R. Botella
Plant Genetic Engineering Laboratory, Department of Botany, School of Integrative Biology, University of
Queensland, Brisbane 4072, Australia.
Root-knot nematodes (Meloidogyne spp.) are obligate, sedentary endoparasites that infect
many plant species causing large economic losses worldwide. They have the ability to infect
hundreds of plant species, which often lack natural resistance. Available nematicides are
being banned due to their toxicity or ozone-depleting properties and alternative control
strategies are urgently required. We have produced transgenic tobacco (Nicotiana tabacum)
plants expressing different dsRNA hairpin structures targeting a root-knot nematode
(Meloidogyne javanica) putative transcription factor, MjTis11. We provide evidence that
MjTis11 was consistently silenced in nematodes feeding on the roots of transgenic plants. The
observed silencing was specific for MjTis11, with other sequence-unrelated genes being
unaffected in the nematodes. Those transgenic plants able to induce silencing of MjTis11,
also showed the presence of small interfering RNAs. Even though down-regulation of
MjTis11 did not result in a lethal phenotype, this study demonstrates the feasibility of
silencing root-knot nematode genes by expressing dsRNA in the host plant. Host Delivered
RNA Interference-triggered (HD-RNAi) silencing of parasite genes provides a novel disease
resistance strategy with wide biotechnological applications. The potential of HD-RNAi is not
restricted to parasitic nematodes but could be adapted to control other plant-feeding pests.
Transcriptome Analysis of Syncytia Induced by the Cyst Nematode
Heterodera schachtii in Arabidopsis and Role of Myo-Inositol Oxygenase
Genes for its Induction and Maintenance
Siddique, S. (1), S. Endreas (2), D. Szakasits (1), K. Wieczorek (1), J. Hofmann (1), F.M.W.
Grundler (1), R. Tenhaken (2) & H. Bohlmann (1)
(1) Institute of Plant Protection, Department of Applied Plant Sciences and Plant Biotechnology, University of
Natural Resources and Applied Life Sciences, Vienna, Austria; (1) University of Salzburg, Plant Physiology,
Hellbrunnerstr. 34, A-5020 Salzburg, Austria
Arabidopsis thaliana is a host for the sugar beet cyst nematode Heterodera schachtii.
Juvenile nematodes invade the roots and induce the development of a syncytium which
functions as a feeding site for the nematode. We report here the transcriptome of syncytia
induced in the roots of Arabidopsis. Microaspiration was employed to harvest pure syncytium
material which was then used to prepare RNA for hybridization to Affymetrix GeneChips.
Initial data analysis showed that gene expression in syncytia at 5 and 15 days after infection
was not much different and both time points were therefore compared together to control
roots. Out of a total of 21,138 genes, 18.4% (3,893) had a higher expression level and 15.8%
5 th International Congress of Nematology, 2008 176