Ericoid mycorrhizal fungi are common root inhabitants of non-Ericaceae plants in a south-eastern Australian sclerophyll forest

Fungi were isolated from the roots of 17 plant species from the families Apiaceae, Cunoniaceae, Cyperaceae, Droseraceae, Fabaceae-Mimosoideae, Lomandraceae, Myrtaceae, Pittosporaceae, Proteaceae and Stylidiaceae at a sclerophyll forest site in New South Wales, Australia. Internal transcribed spacer (ITS) restriction fragment length polymorphism (RFLP) and sequence comparisons indicated that the isolated fungi had affinities to a range of ascomycetes, basidiomycetes and zygomycetes. Four RFLP types had closest affinities to previously identified Helotiales ericoid mycorrhizal (ERM) or Oidiodendron spp. Isolates representing six RFLP types, which were variously isolated from all 17 plant species, formed ERM coils in hair root epidermal cells of Woollsia pungens (Ericaceae) under gnotobiotic conditions. Three of these isolates formed intercellular hyphae, intracellular hyphae and/or microsclerotia, which are typical of dark septate endophyte infection, in roots of Stylidium productum (Stylidiaceae), indicating an ability to form different types of association with roots of different hosts. Overall the data indicate that a broad range of plant taxa may act as repositories for ERM fungi in sclerophyll forest soil. © 2008 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved

Response of soil microbial communities to management strategies for enhancing Scots pine (Pinus sylvestris) establishment on heather (Calluna vulgaris) moorland

Active management to encourage the expansion of native pine woodland onto neighbouring moorland has been suggested as a tool to promote increases in forest area to combat climate change. Low intensity burning has previously been shown to increase pine seedling establishment, however the effect of this on below-ground diversity and functioning in these important terrestrial carbon stores is equivocal. Here, we assessed the effect of a single burn and grazing exclosures after a 6 year period on soil microbial respiratory activity and fungal community structure using terminal restriction fragment polymorphism (T-RFLP) analysis. The combined data suggest that the strategy of a single prescribed burn to facilitate Scots pine establishment had no lasting effect on either fungal taxonomic richness, fungal community composition or microbial activity. Thus, our findings support the proposed use of single, low intensity, prescribed burns in regenerating Scots pine forests as a low impact management tool. © 2010 Springer Science+Business Media B.V

Soil fungal communities differ in native mixed forest and adjacent Araucaria cunninghamii plantations in subtropical Australia

Purpose: Commercial monoculture plantations of the native Australian Araucaria cunninghamii are common in subtropical and tropical Queensland and are generally established following clearing of native mixed forest. The consequences of such forest conversion for soil fungal communities, however, have not been assessed in detail. Materials and methods: We utilised direct DNA extraction from soil coupled with terminal restriction fragment length polymorphism (T-RFLP) analysis of rDNA internal transcribed spacer (ITS) regions to investigate soil fungal community structure under native mixed forest and first and second rotation A. cunninghamii plantations at Yarraman State Forest, Queensland, Australia. We also investigated the influence of forest harvest residue windrows on soil fungi in a second rotation A. cunninghamii plantation and compared soil fungal communities in soil with those in sand-filled hyphal ingrowth bags buried at the site. Results and discussion: Ordination analysis of the fungal community T-RFLP data indicated significant separation of native forest soil samples from the plantation forest soil samples along canonical axis 1, while with first rotation plantation forest soil samples separated from second rotation forest soil samples along canonical axis 2. Fungal communities in soil and hyphal ingrowth bag samples were also shown to differ significantly for the three forest types, suggesting that the hyphal ingrowth bags selected for certain fungi at the site. Windrow soil samples did not separate significantly from nonwindrow soil samples in the second rotation A. cunninghamii plantation. Mean terminal restriction fragment numbers were significantly lower in the A. cunninghamii plantation samples than in the native forest samples and lower in the second rotation than the first rotation plantations. Terminal restriction fragment numbers were also lower in the hyphal ingrowth bag samples than in the respective soil samples. Analysis of cloned ITS sequences indicated that Ascomycota were most abundant, followed by Basidiomycota and Zygomycota; however, their relative importance varied in the different forest types. Conclusions: Overall, the data suggest that conversion of native mixed forest to A. cunninghamii plantations changes soil fungal community composition and that the effect is more pronounced in second rotation forests. © 2010 Springer-Verlag

Converting Australian tropical rainforest to native Araucariaceae plantations alters soil fungal communities

Native rainforest tree plantations are increasingly viewed as potentially important for high value timber production and provision of a range of ecological services in tropical and subtropical areas. In order to determine the extent to which conversion of rainforest to native Araucariaceae plantation influences soil fungi, we compared soil fungal communities under native rainforest and 73-74 year-old Araucaria bidwillii, Araucaria cunninghamii and Agathis robusta plantations at Gadgarra State Forest, Queensland, Australia. Following direct extraction of DNA from soil, terminal restriction fragment length polymorphism (T-RFLP) analysis of rDNA internal transcribed spacer (ITS) regions was conducted. Ordination analysis of the T-RFLP data revealed significant separation of the fungal communities according to forest type along the first canonical axis, with the native rainforest samples separating from the three Araucariaceae plantations along the second axis. Overall, the most abundant ITS sequences in clone assemblages from the four forest types were Ascomycota, followed by Basidiomycota, Zygomycota and Chitridomycota, however their relative importance varied in individual forest types. The results indicate that conversion of tropical rainforest to monoculture plantations of native trees can significantly alter soil fungal diversity. © 2009 Elsevier Ltd. All rights reserved

Identical genotypes of an ericoid mycorrhiza-forming fungus occur in roots of Epacris pulchella (Ericaceae) and Leptospermum polygalifolium (Myrtaceae) in an Australian sclerophyll forest

Assemblages of fungi associated with roots of cooccurring Epacris pulchella (Ericaceae) and Leptospermum polygalifolium (Myrtaceae) seedlings at a sclerophyll forest site in New South Wales, Australia, were investigated by direct DNA extraction and analysis of rRNA gene internal transcribed spacer (ITS) products by denaturing gradient gel electrophoresis (DGGE) and terminal restriction fragment length polymorphism (T-RFLP) analyses. While ordination of the DGGE data suggested that the assemblages did not differ significantly between the two plant taxa, T-RFLP data provided marginal statistical support for the presence of different assemblages. Fungi isolated from roots of both plants were identified by ITS sequence comparisons largely as ascomycetes, several of which had close sequence identity to Helotiales ericoid mycorrhizal (ERM) fungi. One isolate morphotype from E. pulchella had close sequence similarity to ectomycorrhizal fungi in the Cenococcum geophilum complex, and neighbour-joining analysis grouped this strongly with other Australian C. geophilum-like sequences. Distribution of genotypes of an ERM Helotiales ascomycete in root systems of the two plant taxa was also investigated using inter-simple sequence repeat (ISSR)-PCR. Nineteen ISSR genotypes were identified, two of which were present in roots of both plant taxa. The results are discussed in the context of potential mycelial connections between Ericaceae and non-Ericaceae plants. © 2008 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved

Diversity of soil and rhizosphere fungi under Araucaria bidwillii (Bunya pine) at an Australian tropical montane rainforest site

Abstract Samples of rhizosphere soil and bulk soil were collected from under Araucaria bidwillii in a tropical montane rainforest at Mount Lewis forest reserve, Queensland, Australia. DNA was extracted from soil and denaturing gradient gel electrophoresis (DGGE) profiles of PCRamplified partial rDNA internal transcribed spacer (ITS) regions of rhizosphere and bulk soil samples compared. Neither canonical analysis of the principal coordinates nor principal component analysis revealed clear separation of soil samples according to their origin in rhizosphere or bulk soil. Following amplification of rDNA ITS regions using the primers ITS1-F and ITS4, restriction fragment length polymorphism (RFLP) and sequence analyses were also used to identify fungal sequences that were present in clone assemblages from rhizosphere soil and bulk soil. A total of fifty-three RFLP types were thus identified, with the majority being ascomycetes and the remainder basidiomycetes or zygomycetes. Nine RFLP types had affinity with Mortierellaceae, and phylogenetic analysis indicated that these probably represent multiple Mortierella species in both rhizosphere and bulk soil samples. Similar evidence was obtained for the presence of multiple Trichosporon species. RFLP type 53 from a bulk soil sample was identified as a Soil Clone Group I ascomycete, confirming the widespread occurrence of this group. © Kevin D. Hyde 2009