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Biofuels study gives clue to forest ecosystems

15 July 2011

The genome of a dry rot fungus has revealed how it can cause severe damage to buildings. The findings could help in the development of biofuels and may explain how conifer forests evolved.

In 2007 the US Department of Energy’s Joint Genome Institute sequenced Serpula lacrymans in order to see if the way it breaks down cellulose in wood could be harnessed for biofuel production. An international team analysing the genome have found the enzyme mechanisms that could explain the aggressive decay caused by this form of dry rot. These may help develop new pretreaments for biofuel production from agricultural wastes.

A report of the research is published in this week’s Science.

‘Alongside looking at the relevance for biofuels we also compared the genome of this fungus to the genomes of ten forest fungi. What we discovered is that the development by fungi of more sophisticated ways of breaking down wood seems to have gone hand-in-hand with the evolution of conifer forests,’ said Dr Sarah Watkinson of Oxford University’s Department of Plant Sciences, who led the team with Dan Eastwood of the University of Swansea.

Dr Watkinson said: ‘Brown rot fungi like the dry rot fungus leave behind carbon-rich lignin, because they have evolved the ability to extract digestible cellulose and leave the part of the wood they can't use as reddish-brown waste which takes decades to decompose. These fungi give northern conifer forests from the Rockies to Siberia their special carbon-rich, nutrient-poor soils, and this might even be the reason for the reddish brown colour of squirrels and pine martens, camouflaged against the residues from fungal wood decay.’

Conifer forests are a major terrestrial carbon sink with the soil residues of brown dry rot fungi contributing up to 30% of the carbon found in conifer forest soils.

For more information contact Dr Sarah Watkinson on +44 (0)1993 811561 or email sarah.watkinson@plants.ox.ac.uk

Alternatively contact the University of Oxford Press Office on +44 (0)1865 283877 or email press.office@admin.ox.ac.uk

Notes for editors

  • A report of the research, entitled ‘The plant cell wall decomposing machinery underlies the functional diversity of forest fungi’, is published in this week’s Science.
  • The research was headed by Drs Sarah Watkinson, Department of Plant Sciences, University of Oxford, and Dan Eastwood, University of Swansea, in collaboration with the USA Department of Energy Joint Genome Institute (JGI), the project involves 47 experts from 21 laboratories across 10 countries.
  • The ancestors of today’s wood-eating fungi possessed enzymes that broke down all the components of wood, not only the cellulose that they use as food but also the lignin encasing the cellulose fibres. Some species of fungi, including Serpula lacrymans, then lost the enzyme systems that decay lignin and evolved a more efficient process, called brown rot wood decay, which extracts only the cellulose from wood, leaving the lignin behind.
  • Analyses of the genome data shows that forest trees and forest fungi then diversified in parallel around 200-100 million year ago. Over time phenol waste material derived from lignin, which was generated by brown rot fungi feeding on wood, began to saturate forest soils. This waste binds nitrogen and reduces soil fertility creating the kind of conifer forest environments seen in many parts of the world today.