Biological control of the dry rot fungus <i>Serpula lacrymans</i>

<i>Serpula lacrymans</i> causes wood decay, which is of major economic importance in many areas of the world and in the U.K. alone £400 million pounds worth of damage is caused on an annual basis. Conventional treatment regimes for wood decay caused by the wood decay basidiomycete <i>Serpula lacrymans</i> involve the removal of infected timber, the removal of non-infected timber around the infection site and the use of powerful fungicides. Depending upon the scale of the infection the treatment can be expensive and misidentification of the fungus causing the decay is not unknown. Health and environmental problems can arise with the use of the fungicides and removal of timber, in particular that of historical or artistic value, is not always desirable.<br/><br/>Biological control of wood decay fungi has been proposed for a number of years and previous investigations have indicated that control of decay fungi is possible. However, there were a number of problems reported, in particular, the extrapolation of the laboratory work into the field situation. It has been shown that <i>Trichoderma </i>isolates are antagonistic towards <i>S. lacrymans</i> on several media types and wood, with wood colonised initially by <i>Trichoderma </i>isolates resistant to infection by <i>S.lacrymans</i>. Screening experiments, carried out on different media and wood, provided a <i>Trichoderma </i>isolate that would be used in the medium-scale and field trial experiments. The screening experiments indicated that nutrient composition is important for the effectiveness of the <i>Trichoderma </i>isolates, with a high nitrogen level increasing the antagonistic effectiveness. Through the development of a small scale wood interaction system it was determined that certain <i>Trichoderma </i>isolates could prevent the decay of wood by <i>S.lacrymans</i>. However, the <i>S.lacrymans</i> developed specialised hyphal structures (strands) to bypass the <i>Trichoderma </i>colonised portions of the wood.<br/><br/>The medium-scale and field trial experiments indicated that <i>Trichoderma </i>could be used to protect wood from decay and prevent the spread of <i>S.lacrymans</i>. However, the existing <i>S.lacrymans</i> colony could not be killed although it could be induced to produce fruit-bodies by the direct application of the <i>Trichoderma </i>to the <i>S.lacrymans</i>. A PCR system was developed to detect the spread of both <i>S.lacrymans</i> and <i>Trichoderma </i>through wood. Although the <i>Trichoderma </i>could not be detected, the <i>S.lacrymans</i> could be detected in wood sections not visually infected with<i> S.lacrymans</i>.<br/><br/>Extracellular enzyme studies indicated that the phenoloxidase enzyme laccase was important in the defensive strategy of <i>S.lacrymans</i> and in the offensive strategy of <i>Trichoderma </i>isolates. These studies also showed that <i>S.lacrymans</i> may use laccase as a general stress enzyme as laccase was detected during antagonistic, nutritional and temperature stress situations.

Name dc:type.qualificationname

PhD

Level dc:type.qualificationlevel

Doctoral Thesis

Grantor dc:publisher.institution

University of Abertay Dundee

Year dc:date.issued

1998

Author dc:creator

• Score, Alan

Advisor dc:contributor.advisor

• Palfreyman, John

Language dc:language

eng

Identifier

oai:rke.abertay.ac.uk:studenttheses/70c1e296-8317-44db-899a-046dcd0bac46

OAI identifier oai:identifier

oai:rke.abertay.ac.uk:studenttheses/70c1e296-8317-44db-899a-046dcd0bac46