ABSTRACT
Biogenic methane in subsurface coal seam environments is produced by diverse consortia of microbes. Although this methane is useful for global energy security, it remains unclear which microbes can liberate carbon from the coal. Most of this carbon is relatively resistant to biodegradation, as it is contained within aromatic rings. Thus, to explore for coal-degrading taxa in the subsurface, this study reconstructed relevant metagenome-assembled genomes (MAGs) from coal seams by using a key genomic marker for the anaerobic degradation of monoaromatic compounds as a guide: the benzoyl-CoA reductase gene (bcrABCD). Three MAGs were identified with this genetic potential. The first represented a novel taxon from the Krumholzibacteriota phylum, which this study is the first to describe. This Krumholzibacteriota MAG contained a full set of genes for benzoyl-CoA dearomatization, in addition to other genes for anaerobic catabolism of monoaromatics. Analysis of Krumholzibacteriota MAGs from other environments revealed that this genetic potential may be common, and thus, Krumholzibacteriota may be important organisms for the liberation of recalcitrant carbon in a broad range of environments. Moreover, the assembly and characterization of two Syntrophorhabdus aromaticivorans MAGs from different continents and a Syntrophaceae sp. MAG implicate the Deltaproteobacteria class in coal seam monoaromatic degradation. Each of these taxa are potential rate-limiting organisms for subsurface coal-to-methane biodegradation. Their description here provides some understanding of their function within the coal seam microbiome and will help inform future efforts in coal bed methane stimulation, anoxic bioremediation of organic pollutants, and assessments of anoxic, subsurface carbon cycling and emissions.IMPORTANCESubsurface coal seams are highly anoxic, oligotrophic environments, where the main source of carbon is "locked away" within aromatic rings. Despite these challenges, many coal seams accumulate biogenic methane, implying that the coal seam microbiome is "unlocking" this carbon source in situ. For over two decades, researchers have endeavored to understand which organisms perform these processes. This study provides the first descriptions of organisms with this genetic potential from the coal seam environment. Here, we report metagenomic insights into carbon liberation from aromatic molecules and the degradation pathways involved and describe a Krumholzibacteriota, two Syntrophorhabdus aromaticivorans, and a Syntrophaceae MAG that contain this genetic potential. This is also the first time that the Krumholzibacteriota phylum has been implicated in anaerobic dearomatization of aromatic hydrocarbons. This potential is identified here in numerous MAGs from other terrestrial and marine subsurface habitats, implicating the Krumholzibacteriota in carbon-cycling processes across a broad range of environments.
Subject(s)
Coal , Deltaproteobacteria , Coal/microbiology , Carbon/metabolism , Methane/metabolism , Deltaproteobacteria/metabolismABSTRACT
INTRODUCTION: Lower limb ischaemia secondary to occlusion of a lower limb artery is a limb-threatening condition that can be effectively treated by catheter-directed thrombolysis (CDT). The purpose of this study was to examine treatment outcomes of CDT both at the time of treatment and ongoing patency up to 12 months following treatment. The secondary aim of the study was to investigate the influence of age of occlusion and treatment duration on success and complication rates. METHOD: A retrospective observational study was performed at a single institution over a 10-year period from 2010 to 2019. Data for patient demographics, vessel occlusion factors and treatment information were obtained and analysed. Patency data were investigated using Kaplan-Meier analyses. RESULTS: A total of 218 limbs in 159 patients were treated during the study period. The aetiology of vessel occlusion was in situ thrombosis or occluded bypass graft in 74.5%. Technical success was achieved in 55.5% with CDT alone and 84.4% by using CDT in combination with adjunctive endovascular procedures (angioplasty or stenting). The overall probability of patency was 0.65 at 3 months and 0.44 at 12 months. The overall rate of major amputation within 30 days of thrombolysis was 8.2%. Thirty-day mortality was 6.3% and was secondary to intracranial haemorrhage in three patients. CONCLUSION: Technical success of CDT was found to be significantly higher when combined with adjunctive endovascular procedures at the time of CDT. Despite an initial moderate technical success, the probability of patency at 12 months was only 44%. The likelihood of bleeding complications and technical and long-term success remain key considerations when selecting patients for CDT.
Subject(s)
Arterial Occlusive Diseases , Endovascular Procedures , Peripheral Vascular Diseases , Humans , Retrospective Studies , Thrombolytic Therapy/adverse effects , Thrombolytic Therapy/methods , Vascular Patency , Treatment Outcome , Ischemia/therapy , Ischemia/drug therapy , Catheters/adverse effects , Risk FactorsABSTRACT
One of the most abundant and ubiquitous taxa observed in eastern Australian coal seams is an uncultured Desulfuromonas species and part of the Coal Seam Microbiome dataset assigned as 'CSMB_57'. Despite this abundance and ubiquity, knowledge about this taxon is limited. The present study aimed to generate an enrichment culture of Desulfuromonas sp. 'CSMB_57' using culturing strategies that exploit its sulphur-reducing capabilities by utilizing a polysulfide solution in a liquid medium. Using dilution to extinction methods, a highly enriched culture was successfully generated. The full-length 16S rRNA sequence revealed that all closely related taxa were observed in subsurface environments suggesting that D. sp. 'CSMB_57' may be a subsurface specialist. Subsequently, the DNA from the enrichment culture was sequenced and the genome of D. sp. 'CSMB_57' was assembled. Genomic annotation revealed a high number of CRISPR arrays for viral defence, a large array of ABC transporters for amino acid and peptide uptake, as well as genes likely associated with syntrophy such as genes associated with type-IVa pilus, often used for direct interspecies electron transfer, and multiple hydrogenases capable of producing hydrogen. From the various genomic observations, a conceptual ecological model was developed that explores its possible syntrophic roles with hydrogenotrophic methanogens and acetogenic bacteria within coal-seam environments.
Subject(s)
Coal , Desulfuromonas , Australia , Bacteria , Coal/microbiology , Desulfuromonas/genetics , Genomics , RNA, Ribosomal, 16S/geneticsABSTRACT
The production of methane as an end-product of organic matter degradation in the absence of other terminal electron acceptors is common, and has often been studied in environments such as animal guts, soils and wetlands due to its potency as a greenhouse gas. To date, however, the study of the biogeographic distribution of methanogens across coal seam environments has been minimal. Here, we show that coal seams are host to a diverse range of methanogens, which are distinctive to each geological basin. Based on comparisons to close relatives from other methanogenic environments, the dominant methanogenic pathway in these basins is hydrogenotrophic, with acetoclastic being a second major pathway in the Surat Basin. Finally, mcrA and 16S rRNA gene primer biases were predominantly seen to affect the detection of Methanocellales, Methanomicrobiales and Methanosarcinales taxa in this study. Subsurface coal methanogenic community distributions and pathways presented here provide insights into important metabolites and bacterial partners for in situ coal biodegradation.
Subject(s)
Euryarchaeota , Greenhouse Gases , Animals , Archaea/metabolism , Coal/microbiology , Euryarchaeota/genetics , Greenhouse Gases/metabolism , Methane/metabolism , Phylogeny , RNA, Ribosomal, 16S/genetics , RNA, Ribosomal, 16S/metabolism , SoilABSTRACT
The global trend of transiting to more renewable energy sources requires transition fuels, such as coal seam gas, to supplement and secure energy needs. In order to optimise strategies and technologies for enhancing gas production, an understanding of the fundamental microbial processes and interactions would be advantageous. Models have recently begun mapping the microbial roles and interactions in coal seam environments, from direct coal degradation to methanogenesis. This study seeks to expand those models by observing community compositional shifts in the presence of differing organic matter by conducting 16S rRNA microbial surveys using formation water from the Surat and Sydney Basins grown on varying types of organic matter (black and brown coal, oil shale, humic acid, and lignin). A total of 135 microbes were observed to become enriched in the presence of added organic matter in comparison to carbon-free treatments. These surveys allowed detailed analysis of microbial compositions in order to extrapolate which taxa favour growth in the presence of differing organic matter. This study has experimentally demonstrated shifts in the microbial community composition due to differing carbon sources and, for the first time, generated a conceptual model to map putative degradation pathways regarding subsurface microbial consortia.
Subject(s)
Coal , Microbiota , RNA, Ribosomal, 16S/genetics , Methane/metabolism , Microbial Consortia/geneticsABSTRACT
Subsurface coal seams contain microbial consortia with various taxa, each with a different role in the degradation of coal organic matter. This study presents the sequenced and annotated genome of Desulfovibrio sp. strain CSMB_222, a bacterium isolated from eastern Australian coal seams.
ABSTRACT
Competitive behaviours of plant growth promoting rhizobacteria (PGPR) are integral to their ability to colonize and persist on plant roots and outcompete phytopathogenic fungi, oomycetes and bacteria. PGPR engage in a range of antagonistic behaviours that have been studied in detail, such as the production and secretion of compounds inhibitory to other microbes. In contrast, their defensive activities that enable them to tolerate exposure to inhibitory compounds produced by their neighbours are less well understood. In this study, the genes involved in the Pseudomonas protegens Pf-5 response to metabolites from eight diverse rhizosphere competitor organisms, Fusarium oxysporum, Rhizoctonia solani, Gaeumannomyces graminis var. tritici, Pythium spinosum, Bacillus subtilis QST713, Pseudomonas sp. Q2-87, Streptomyces griseus and Streptomyces bikiniensis subspecies bikiniensi, were examined. Proximity induced excreted metabolite responses were confirmed for Pf-5 with all partner organisms through HPLC before culturing a dense Pf-5 transposon mutant library adjacent to each of these microbes. This was followed by transposon-directed insertion site sequencing (TraDIS), which identified genes that influence Pf-5 fitness during these competitive interactions. A set of 148 genes was identified that were associated with increased fitness during competition, including cell surface modification, electron transport, nucleotide metabolism, as well as regulatory genes. In addition, 51 genes were identified for which loss of function resulted in fitness gains during competition. These included genes involved in flagella biosynthesis and cell division. Considerable overlap was observed in the set of genes observed to provide a fitness benefit during competition with all eight test organisms, indicating commonalities in the competitive response to phylogenetically diverse micro-organisms and providing new insight into competitive processes likely to take place in the rhizosphere.
Subject(s)
Oomycetes , Rhizosphere , Bacillus subtilis , Pseudomonas/geneticsABSTRACT
Methane is an important energy resource internationally, and a large proportion of this methane is produced by microbial communities living in coal seams. Despite the value of this resource for human energy security, our understanding of the metabolic roles played by specific taxa during the biodegradation of coal to methane in situ is quite limited. In order to develop a greater understanding of microbial catabolism on coal, a community from a coal seam in the Surat Basin, Australia, was incubated on 10 different aromatic organic compounds: coronene, benzo[a]pyrene, pyrene, phenanthrene, naphthalene, ethylbenzene, phenol, benzoate, vanillate and syringate. Each of these aromatic compounds either occurs in coal or is a possible product of the coal biodegradation process. 16S rRNA sequencing revealed substantial changes to each community in response to each aromatic carbon substrate provided. Abundant taxa from these substrate-specific communities were identified and their probable catabolic roles proposed based on literature searches of related taxa. This study is the first to link specific coal seam taxa to aromatic substrates available in coal seam environments. Two conceptual models of the putative degradation pathways and key taxa responsible are proposed.
Subject(s)
Coal , Microbiota , Australia , Humans , Methane , RNA, Ribosomal, 16S/geneticsABSTRACT
Subsurface coal seams harbor an array of diverse microbial species subsisting as a community on the organic matter present in coal. Here, we present the annotated genome sequence of Dietzia sp. strain SYD-A1, a bacterium isolated from a terrestrial subsurface coal seam in New South Wales, Australia.
ABSTRACT
Diverse microbial communities living in subsurface coal seams are responsible for important geochemical processes including the movement of carbon between the geosphere, biosphere and atmosphere. Microbial conversion of the organic matter in coal to methane involves a complex assemblage of bacteria and archaea working in syntrophic relationships. Despite the importance and value of this microbial process, very few of the microbial taxa have defined metabolic or ecological roles in these environments. Additionally, the genomic features mediating life in this chemically reduced, energy poor, deep subsurface environment are not well characterised. Here we describe the isolation and genomic and catabolic characterisation of three alphaproteobacterial Stappia indica species from three coal basins across Australia. S. indica genomes from coal seams were compared with those from closely related S. indica isolated from diverse surface waters, revealing a coal seam-specific suite of genes associated with life in the subsurface. These genes are linked to processes including viral defence, secondary metabolite production, polyamine metabolism, polypeptide uptake membrane transporters and putative energy neutral pressure-dependent CO2 fixation. This indicates that subsurface Stappia have diverse metabolisms for biomass recycling and pressure-dependent CO2 fixation and require a suite of defensive and competitive strategies relative to their surface-dwelling relatives.
Subject(s)
Carbon Cycle , Fresh Water/microbiology , Genome, Bacterial , Geologic Sediments/microbiology , Rhodobacteraceae/physiology , Biomass , Coal , Mining , New South Wales , Queensland , Rhodobacteraceae/genetics , Rhodobacteraceae/isolation & purification , Species SpecificityABSTRACT
Microbes in subsurface coal seams are responsible for the conversion of the organic matter in coal to methane, resulting in vast reserves of coal seam gas. This process is important from both environmental and economic perspectives as coal seam gas is rapidly becoming a popular fuel source worldwide and is a less carbon intensive fuel than coal. Despite the importance of this process, little is known about the roles of individual bacterial taxa in the microbial communities carrying out this process. Of particular interest is the role of members of the genus Pseudomonas, a typically aerobic taxa which is ubiquitous in coal seam microbial communities worldwide and which has been shown to be abundant at early time points in studies of ecological succession on coal. The current study performed aerobic isolations of coal seam microbial taxa generating ten facultative anaerobic isolates from three coal seam formation waters across eastern Australia. Subsequent genomic sequencing and phenotypic analysis revealed a range of ecological strategies and roles for these facultative anaerobes in biomass recycling, suggesting that this group of organisms is involved in the degradation of accumulated biomass in coal seams, funnelling nutrients back into the microbial communities degrading coal to methane.
Subject(s)
Coal/microbiology , Microbiota/physiology , Pseudomonas/growth & development , Anaerobiosis/physiology , Australia , Pseudomonas/classificationABSTRACT
Microbial communities in subsurface coal seams are responsible for the conversion of coal organic matter to methane. This process has important implications for both energy production and our understanding of global carbon cycling. Despite the environmental and economic importance of this process, little is known about which components of the heterogeneous coal organic matter are biodegradable under methanogenic conditions. Similarly, little is known about which taxa in coal seams carry out the initial stages of coal organics degradation. To identify the biodegradable components of coal and the microorganisms responsible for their breakdown, a subbituminous coal was fractionated into a number of chemical compound classes which were used as the sole carbon source for growth by a coal seam microbial community. This study identifies 65 microbial taxa able to proliferate on specific coal fractions and demonstrates a surprising level of substrate specificity among members of this coal-degrading microbial consortia. Additionally, coal kerogen, the solvent-insoluble organic component of coal often considered recalcitrant to microbial degradation, appeared to be readily converted to methane by microbial degradation. These findings challenge our understanding of coal organic matter catabolism and provide insights into the catabolic roles of individual coal seam bacteria.
Subject(s)
Coal/microbiology , Methane/biosynthesis , Microbial Consortia , Bacteria/classification , Bacteria/genetics , Bacteria/growth & development , Bacteria/metabolism , Biodegradation, Environmental , Carbon/analysis , Carbon/metabolism , Coal/analysis , Microbial Consortia/genetics , Species SpecificityABSTRACT
INTRODUCTION: Whole-metagenome sequencing can be a rich source of information about the structure and function of entire metagenomic communities, but getting accurate and reliable results from these datasets can be challenging. Analysis of these datasets is founded on the mapping of sequencing reads onto known genomic regions from known organisms, but short reads will often map equally well to multiple regions, and to multiple reference organisms. Assembling metagenomic datasets prior to mapping can generate much longer and more precisely mappable sequences but the presence of closely related organisms and highly conserved regions makes metagenomic assembly challenging, and some regions of particular interest can assemble poorly. One solution to these problems is to use specialised tools, such as Kelpie, that can accurately extract and assemble full-length sequences for defined genomic regions from whole-metagenome datasets. METHODS: Kelpie is a kMer-based tool that generates full-length amplicon-like sequences from whole-metagenome datasets. It takes a pair of primer sequences and a set of metagenomic reads, and uses a combination of kMer filtering, error correction and assembly techniques to construct sets of full-length inter-primer sequences. RESULTS: The effectiveness of Kelpie is demonstrated here through the extraction and assembly of full-length ribosomal marker gene regions, as this allows comparisons with conventional amplicon sequencing and published metagenomic benchmarks. The results show that the Kelpie-generated sequences and community profiles closely match those produced by amplicon sequencing, down to low abundance levels, and running Kelpie on the synthetic CAMI metagenomic benchmarking datasets shows similar high levels of both precision and recall. CONCLUSIONS: Kelpie can be thought of as being somewhat like an in-silico PCR tool, taking a primer pair and producing the resulting 'amplicons' from a whole-metagenome dataset. Marker regions from the 16S rRNA gene were used here as an example because this allowed the overall accuracy of Kelpie to be evaluated through comparisons with other datasets, approaches and benchmarks. Kelpie is not limited to this application though, and can be used to extract and assemble any genomic region present in a whole metagenome dataset, as long as it is bound by a pairs of highly conserved primer sequences.
ABSTRACT
The subsurface represents a largely unexplored frontier in microbiology. Here, coal seams present something of an oasis for microbial life, providing moisture, warmth, and abundant fossilized organic material. Microbes in coal seams are thought to syntrophically mobilize fossilized carbon from the geosphere to the biosphere. Despite the environmental and economic importance of this process, little is known about the microbial ecology of coal seams. In the current study, ecological succession and spatial niche partitioning are explored in three coal seam microbial communities. Scanning electron microscopic visualization and 16S rRNA sequencing track changes in microbial communities over time, revealing distinct attached and planktonic communities displaying patterns of ecological succession. Attachment to the coal surface is biofilm mediated on Surat coal, whereas microbes on Sydney and Gunnedah coal show different attachment processes. This study demonstrates that coal seam microbial communities undergo spatial niche partitioning during periods of succession as microbes colonize coal environments.
ABSTRACT
This study describes a novel ericoid mycorrhizal fungus (ErMF), Gamarada debralockiae Midgley and Tran-Dinh gen. nov. sp. nov. Additionally, catabolism was explored from a genomic perspective. The nuclear and mitochondrial genomes of G. debralockiae were sequenced. Morphological characteristics were assessed on various media. Catabolic genes of G. debralockiae were explored using SignalP and dbCAN. Phylogenetic comparisons were undertaken using Phylogeny.fr. The 58.5-Mbp draft genome of G. debralockiae contained 17,075 putative genes. The complete mitochondrial genome was 28,168 bp in length. In culture, G. debralockiae produces slow-growing non-sporulating colonies. Gamarada debralockiae has many putative secreted catabolic enzymes. Phylogeny indicated G. debralockiae was distinct from known ascomycetous ErMF: Pezoloma ericae, Meliniomyces spp., Oidiodendron spp., and Cairneyella variabilis. It is closely related to many undescribed plant root-associated fungi and its nearest described relative is Hyphodiscus brevicollaris. Gamarada debralockiae has been recovered from virtually all Australian ericoid mycorrhizal studies and biogeographic data suggests the taxon is widespread in Australia. Gamarada debralockiae has similar catabolic potential to C. variabilis and co-occurs with C. variabilis at Australian sites. Plants that host multiple ErMF may benefit from subtle differences in catabolism that improve access to nitrogen and phosphorus from within recalcitrant organic matter.
Subject(s)
Ascomycota/classification , Ericaceae/microbiology , Genome, Fungal , Mycorrhizae/classification , Ascomycota/physiology , Base Sequence , DNA, Intergenic/genetics , Mycorrhizae/physiology , New South Wales , PhylogenyABSTRACT
Elevated uranium dose (4 g kg-1) causes a shift in billabong sediment communities that result in the enrichment of five bacterial species. These taxa include Geobacter, Geothrix and Dyella species, as well as a novel-potentially predatory-Bacteroidetes species, and a new member of class Anaerolineae (Chloroflexi). Additionally, a population of methanogenic Methanocella species was also identified. Genomic reconstruction and metabolic examination of these taxa reveal a host of divergent life strategies and putative niche partitioning. Resistance-nodulation-division heavy metal efflux (RND-HME) transporters are implicated as potential uranium tolerance strategies among the bacterial taxa. Potential interactions, uranium tolerance and ecologically relevant catabolism are presented in a conceptual model of life in this environment.
Subject(s)
Bacteria/genetics , Genomics , Geologic Sediments/microbiology , Metagenome , Uranium/metabolism , Bacteria/classification , Bacteria/enzymology , Bacterial Proteins/genetics , Carbohydrate Metabolism , DNA, Bacterial/genetics , Drug Tolerance , Ecology , Genes, Bacterial/genetics , Geobacter/classification , Geobacter/genetics , Molecular Sequence Annotation , Phylogeny , RNA, Ribosomal, 16S/geneticsABSTRACT
The red macroalga Asparagopsis taxiformis has been shown to significantly decrease methane production by rumen microbial communities. This has been attributed to the bioaccumulation of halogenated methane analogues produced as algal secondary metabolites. The objective of this study was to evaluate the impact of A. taxiformis supplementation on the relative abundance of methanogens and microbial community structure during in vitro batch fermentation. Addition of A. taxiformis (2% organic matter) or the halogenated methane analogue bromoform (5 µM) reduced methane production by over 99% compared to a basal substrate-only control. Quantitative PCR confirmed that the decrease in methane production was correlated with a decrease in the relative abundance of methanogens. High-throughput 16S ribosomal RNA gene amplicon sequencing showed that both treatments reduced the abundance of the three main orders of methanogens present in ruminants (Methanobacteriales, Methanomassiliicoccales and Methanomicrobiales). Shifts in bacterial community structure due to the addition of A. taxiformis and 5 µM bromoform were similar and concomitant with increases in hydrogen concentration in the headspace of the fermenters. With high potency and broad-spectrum activity against rumen methanogens, A. taxiformis represents a promising natural strategy for reducing enteric methane emissions from ruminant livestock.
Subject(s)
Methane/analogs & derivatives , Microbiota/drug effects , Rhodophyta/metabolism , Rumen/microbiology , Seaweed/metabolism , Animals , Bacteria/classification , Bacteria/drug effects , Bacteria/metabolism , DNA, Bacterial/genetics , Fermentation , Halogenation , Hydrogen/metabolism , In Vitro Techniques , Livestock/microbiology , Methane/metabolism , Methanobacteriales/drug effects , Methanobacteriales/metabolism , Methanomicrobiales/drug effects , Methanomicrobiales/metabolism , Microbiota/genetics , RNA, Ribosomal, 16S/genetics , Trihalomethanes/pharmacologyABSTRACT
Located in the Northern Territory of Australia, Ranger uranium mine is directly adjacent to the UNESCO World Heritage listed Kakadu National Park, with rehabilitation targets needed to ensure the site can be incorporated into the park following the mine's closure in 2026. This study aimed to understand the impact of uranium concentration on microbial communities, in order to identify and describe potential breakpoints in microbial ecosystem services. This is the first study to report in situ deployment of uranium-spiked sediments along a concentration gradient (0-4000 mg U kg-1 ), with the study design maximising the advantages of both field surveys and laboratory manipulative studies. Changes to microbial communities were characterised through the use of amplicon and shotgun metagenomic next-generation sequencing. Significant changes to taxonomic and functional community assembly occurred at a concentration of 1500 mg U kg-1 sediment and above. At uranium concentrations of ≥ 1500 mg U kg-1 , genes associated with methanogenic consortia and processes increased in relative abundance, while numerous significant changes were also seen in the relative abundances of genes involved in nitrogen cycling. Such alterations in carbon and nitrogen cycling pathways suggest that taxonomic and functional changes to microbial communities may result in changes in ecosystem processes and resilience.
Subject(s)
Bacteria/genetics , Carbon Cycle/genetics , Geologic Sediments/chemistry , Microbial Consortia/drug effects , Nitrogen Cycle/genetics , ATP-Binding Cassette Transporters/genetics , Australia , Bacteria/classification , Bacteria/metabolism , Base Sequence , Carbon/metabolism , Ecosystem , Geologic Sediments/microbiology , Metagenomics , Methane/metabolism , Mining , Nitrogen/metabolism , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Uranium/metabolism , Uranium/pharmacologyABSTRACT
Aspergillus hancockii sp. nov., classified in Aspergillus subgenus Circumdati section Flavi, was originally isolated from soil in peanut fields near Kumbia, in the South Burnett region of southeast Queensland, Australia, and has since been found occasionally from other substrates and locations in southeast Australia. It is phylogenetically and phenotypically related most closely to A. leporis States and M. Chr., but differs in conidial colour, other minor features and particularly in metabolite profile. When cultivated on rice as an optimal substrate, A. hancockii produced an extensive array of 69 secondary metabolites. Eleven of the 15 most abundant secondary metabolites, constituting 90% of the total area under the curve of the HPLC trace of the crude extract, were novel. The genome of A. hancockii, approximately 40 Mbp, was sequenced and mined for genes encoding carbohydrate degrading enzymes identified the presence of more than 370 genes in 114 gene clusters, demonstrating that A. hancockii has the capacity to degrade cellulose, hemicellulose, lignin, pectin, starch, chitin, cutin and fructan as nutrient sources. Like most Aspergillus species, A. hancockii exhibited a diverse secondary metabolite gene profile, encoding 26 polyketide synthase, 16 nonribosomal peptide synthase and 15 nonribosomal peptide synthase-like enzymes.
Subject(s)
Aspergillus/genetics , Fungi/genetics , DNA, Fungal/genetics , Multigene Family/genetics , Phylogeny , Queensland , Sequence Analysis, DNA/methods , SoilABSTRACT
The prominent ericoid mycorrhizal fungus, Pezoloma ericae, has not been found in Australia to date. In the present study, internal transcribed spacer (ITS) data from the Biomes of Australia Soil Environments (BASE) was searched for evidence of P. ericae and other known ericoid mycorrhizal and root-associated taxa. ITS sequences with high identity to P. ericae, Meliniomyces bicolor, Meliniomyces variabilis, Cairneyella sp. 2, Cadophora finlandica and Woollsia mycorrhizal fungus VI were identified and their distribution in Australia visualised. This is the first evidence that P. ericae, M. bicolor and M. variabilis very likely occur on the Australian continent and provides a set of locations from which to seek isolates for further characterisation. The presence of P. ericae in South America, South Africa, and now Australia suggests a broad and ancient Gondwanan distribution for this well-studied species.