Molecular fungal diversity and its ecological function in sand-dune soils

  • Irma Gonzalez Gonzalez

Student thesis: Phd

Abstract

There are about 100,000 described fungal species, however, the diversity could be higher because conventional techniques do not allow identification of all groups of fungi and there are still unexplored geographical areas. High-throughput DNA sequencing methods provide the opportunity to resolve the diversity and distribution of mycelia in soil. Soils are the largest pool of terrestrial carbon and macromolecular materials, such as lignin and cellulose, form an important part of this soil carbon. Saprotrophs (decomposers) fungi degrade lignin and cellulose that is important to the global carbon cycle, although lignin is highly resistant to degradation if compared with cellulose. In this work, we investigated the diversity of fungi in sand-dune soils and their involvement in the decomposition of lignin and cellulose. The key findings of this work were:•A comparison of sand-dune ecosystems from two reserves in the UK showed differences in the ion concentrations, pH and total organic carbon in soils, suggesting that there were different environmental conditions that could potentially affect the distribution/presence of microbial communities in soils, e.g. fungal communities.•Fungi from field samples were identified using 454 pyrosequencing. The identified fungal species belong to groups with different ecologies, among which are wood-rotting fungi that are the main agents responsible for the lignin breakdown. The fungal communities were distributed differently across the different sand-dune ecosystems, sampling times and type of bait materials.•Lignin and cellulose can be degraded in field samples over time. Lignin degradation was shown by the shifts in the [Ac/Al]S, [Ac/Al]G and [S/G] relative lignin decomposition state proxies, and cellulose degradation by the shifts in the [cellulose:cellulose+lignin] ratio. Cellulose degradation was faster than lignin, thus confirming previous studies.•The degradation of both lignin and cellulose was different depending on the type of plant material, ecosystem/soil characteristics where the material was buried and fungal communities present on the bait materials.•Lignin breakdown was most likely to be by white-rot fungi that were identified colonising the bait materials.
Date of Award1 Aug 2015
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorClare Robinson (Supervisor) & Bart Van Dongen (Supervisor)

Keywords

  • fungi, pyrosequencing, lignin, cellulose, degradation, sand dunes
  • Ainsdale Sand Dunes, Sandsclae Haws

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