TABLE CONTENTS

Molecular Nematology as a Tool for Soil Monitoring
Neilson, R. (1), S. Donn (1), S.N. Vink (1), B.S. Griffiths (2) & T.J. Daniell (1)
(1) SCRI, Dundee, DD2 5DA, Scotland, UK; (2) Teagasc, Environment Research Centre, Johnstown Castle,
Wexford, Co. Wexford, Ireland.
Climate change is now recognized as one of the most important challenges for the planet.
Whilst the gross geophysical changes such as receding glaciers capture the headlines and are
in relative terms simple to measure, the impact upon soil ecosystems is potentially more
difficult to detect due to the resilient nature of soil. The combination of climate change and
constant perturbation by agronomic practices may accelerate degradation of soils in
agricultural zones with soil erosion for example an increasing issue.
Intensive land use has been implicated in declining soil health with concomitant concerns
over sustainability of agronomic production. Monitoring soil health is problematic although
soon to become a reality in the European Union due to forthcoming legislation.
Nematodes have been proposed as indicators of soil health due to their ubiquity, short
generation times and trophic composition, however identification based on morphology is
time consuming and challenging. Previously univariate and multivariate analysis of classical
morphological data have been used to interpret nematode assemblage data with limited
success.
Alternative molecular approaches to profiling soil nematode assemblages have been applied
here, based on Terminal Restriction Fragment Length Polymorphism (T-RFLP) of small
subunit ribosomal DNA. Two approaches are described, the first entailing digestion of
fluorescently labelled PCR product with a single enzyme, combined with multivariate
analysis of the resulting fragment profile. Application of this method on agricultural sites
under differing management regimes revealed significant differences in assemblage
composition by agronomic treatment. The second approach utilises a directed method where,
from collected sequence information, a restriction digest has been designed to separate
nematode taxa present at the study sites into terminal restriction fragments of known size.
We envisage the resulting semi-quantitative profiles may be combined with existing
nematode diversity indices and other soil (a)biotic data as a potential tool to monitor soil
health.
5 th International Congress of Nematology, 2008 93