TABLE CONTENTS

Gene Induction by Desiccation Stress in Anhydrobiotic Nematodes Reveals
Parallels with Drought Tolerance Mechanisms in Plants
Burnell, A.M. (1), T. Tyson (1), A. Shannon (1), W. Reardon (1), J.T. Jones (2)
& M. Blaxter (3)
(1) Biology Department, National University of Ireland Maynooth, Maynooth, Co. Kildare, Ireland; (2) Plant-
Pathogen Interactions Programme, Scottish Crop Research Institute, Invergowrie, Dundee, DD2 5DA, UK; (3)
School of Biological Sciences, University of Edinburgh,King’s Buildings, West Mains Road, Edinburgh EH9
3JT, UK.
Many nematode species have become adapted to withstand extreme desiccation by entering
into a state of suspended animation known as anhydrobiosis. Some nematodes can undergo
anhydrobiosis at all stages of their life cycle, while many plant and animal parasitic
nematodes have anhydrobiotic eggs or infective stages. Some taxa can survive immediate
and prolonged exposure to rapid dehydration. However the majority of anhydrobiotic
nematodes are slow dehydration strategists requiring preconditioning to moderate reductions
in relative humidity to induce the biochemical changes necessary to survive in an
anhydrobiotic state. We have isolated expressed sequence tags (ESTs) that are up-regulated
in response to desiccation in Aphelenchus avenae (a slow dehydration strategist
anhydrobiote) and in the infective stages of the insect parasitic nematode Steinernema
carpocapsae (a desiccation tolerant non-anhydrobiotic nematode). Both datasets contained
sequences which encode putative signalling molecules, transcription factors, antioxidants,
molecular chaperones, C-type lectin sequences, sequences encoding membrane associated
proteins and several distinct LEA sequences. LEAs (= late embryogenesis abundant) are
hydrophilic proteins which occur abundantly in plants and whose expression is associated
with the onset of desiccation tolerance, cold hardiness and seed maturation. Our EST
datasets also contain novel sequences which encode putative hydrophilic and natively
unfolded proteins. It is likely that these novel and putative proteins play an important role in
desiccation tolerance, possibly by carrying out analogous roles in nematodes to those carried
out by the other LEA protein classes in plants. We have recently sequenced 10,000 ESTs
from the fast desiccation strategist nematode Panagrolaimus superbus. We are currently
carrying out a bioinformatics analysis on this dataset. In our presentation we will provide a
summary of the available information on the signaling pathways and molecular adaptations
utilized by anhydrobiotic and desiccation tolerant nematodes.
5 th International Congress of Nematology, 2008 49