Ipek Kurtboke

Globally, various biotic stressors are threatening the production of crops including wheat, cotton, maize, vegetables, fruit and ornamentals with up to 50–75% yield losses caused predominantly by fungal pathogens. One such fungal pathogen is Pyrrhoderma noxium, an aggressive basidiomycete fungus that induces the invasive disease of brown root rot in a variety of tree hosts, spanning over 250 species. This mini review will focus on various characteristics of this pathogen which is now a widespread across tropical and subtropical regions of the world infecting broad-leaved, coniferous woody, herbaceous, fruit and ornamental trees with examples of the research conducted at the University of the Sunshine Coast jointly with the Brisbane City Council.

The genus Micromonospora (Ørskov 1923) is a Gram-positive, chemo-organotrophic, aerobic actinomycete, the second most predominant genus of the phylum Actinomycetota in natural environments after the genus Streptomyces, and has provided many clinically significant antibiotics, mostly aminoglycosides like gentamicin. This mini review will highlight the occurrence of this genus in diverse environments and its importance for natural product discovery and biotechnology.

Since 2003, large foaming events resembling ‘chocolate mousse-like foam’ have been reported along several popular beaches on the Sunshine Coast, Queensland, Australia, following storms and turbulent sea water events. Earlier studies at the University of the Sunshine Coast (UniSC) first highlighted that these foaming events contained an abundance of filamentous actinomycete species, specifically from the genus Nocardia. Species of this genus are frequently detected in the foams of sewage treatment plants during the activated sludge process. Nocardiae can form an extensive mycelial network and trap fats, oil and grease, which exacerbates foam formation. In addition, Nocardia species are known to be pathogenic and cause various diseases including nocardiosis in human and animal hosts. This review focusses on the occurrence, diversity and virulence properties of Nocardia species with examples of isolations of Nocardiae from foaming coastal marine waters of the region.

Actinomycetes are ubiquitous bacteria found in many different niches with superior metabolic capabilities resulting in the production of many potent bioactive compounds. Since the 1940s, most notably, the members of the order Streptomycetales have yielded many clinically important antibiotics and antimicrobial compounds starting with actinomycin and streptomycin. In this paper, recent advances in metabolic engineering as well as the use of artificial intelligence will be discussed as they are undoubtedly increasing the chances of discovery of novel bioactive compounds from the unexhausted natural product machinery of actinomycetes.

A FAO 2024 report1 noted that aquaculture production worldwide has excelled, and aquaculture produced surpassed captured fish resulting in an increase of 4.4% in 2022 compared to 2020. Production comprised 185.4 × 106 tonnes of aquatic animals and 37.8 × 106 tonnes of algae, which is also used as feed in the industry. These figures indicate that aquaculture production will continue to expand and will be one of the fastest growing sectors for food-production into coming decades. Bivalve molluscs will likely remain a major component of this production. However, the microbial infestation of bivalves and their microalgal feeds and subsequent disease occurrences are of significant concern. This article highlights the use of bacteriophages to eliminate pathogenic bacterial species in environments where bivalves are cultivated so they can be protected from bacterial diseases.

The suite of fungi that associate with mosses, bryophilous fungi, can be explored further to provide insights into the symbiotic functionality of mosses as well as the ecosystems in which they reside. So far, in-depth studies on the taxonomic diversity, ecology, and physiological functions of bryophilous fungi associated with the Australasian moss species Leucobryum candidum are lacking. To generate information on the physiology, biology, and ecology of these organisms and their interactions with the moss host, the combined use of selective isolation and molecular characterisation of the fungal associates was carried out. Once the pure cultures of the fungal associates were obtained, a bioactivity assay was used to investigate the effect of fungal metabolites on moss growth in vitro. Overall, L. candidum species collected from six different locations within Southeast Queensland exposed to different environmental parameters were found to have a highly diverse community of fungal species from 10 orders and 17 families. A total of 25 of the 33 isolates that were identified using molecular sequencing techniques were unique species, confirming high beta diversity of the fungal associates of L. candidum collected from coastal, forest, and urban environments in Southeast Queensland. The highest numbers of culturable isolates came from coastal and forest sites. Urban sites accounted for the lowest numbers of culturable isolates. The taxonomic matches for these associates were known to have diverse endophytic, saprophytic, and parasitic roles within vascular plants. Selected moss samples were inoculated with fermentation extracts of fungal isolates (USC-F426 and USC-F427) and their effects on the moss samples were observed for any change in heights, weights, diameters, and morphological characteristics. A significant (p ≤ 0.05) difference in the heights of the in vitro-assessed L. candidum between treatments was observed. No significant differences, however, were seen between the weights and diameters and no discernible host symptoms were detected, other than a few morphological change observations.

The 2024 International Union of Microbiological Societies Congress was held in Florence, the city of Renaissance. The theme was to increase the awareness of the power of microbial life, recognizing that it can lead the transformation towards a sustainable planet. The meeting gathered over 1400 experts from more than 90 countries and focused on the transformative potential of microbiology in addressing global challenges and aligning microbial science with the Sustainable Development Goals. Six roundtable discussions explored the pivotal role of microbiology in mitigating climate change, preparing for pandemics, producing sustainable energy, promoting a One Health approach, understanding microbiome dynamics, and developing data infrastructure. The discussions revealed that microbes are still overlooked agents in sustainable solutions. Expert panellists at the roundtables discussed microbial innovations in hydrogen and biofuel production, conversion of greenhouse gases, biomanufacturing, and soil restoration, the role of microbiome in immune health, the importance of cross-kingdom interactions, and the integration of food, environmental, and microbiomes under the One Health framework. Panels stressed the need for equitable access to vaccines, diagnostics, and data sharing, especially in the face of antimicrobial resistance. The importance of global collaboration, data repositories, and regulatory alignment, was repeatedly emphasized. The congress invited calls for the formation of an international microbiology coalition, need for interdisciplinary partnerships, increased investment in microbial technologies, updating of regulatory frameworks, and integration of microbiome science into public health and environmental policy. Microorganisms are the oldest architects of nature, able to build a sustainable future for the planet.

Introduction: Pyrrhoderma noxium is a plant pathogen that causes economic losses in agricultural and forestry industries, including significant destruction to amenity trees within the city of Brisbane in Australia. Use of chemical control agents are restricted in public areas, there is therefore an urgent need to investigate biological control approaches. Members of the phylum Actinomycetota, commonly known as actinomycetes, are known for their industrially important secondary metabolites including antifungal agents. They have proven to be ideal candidates to produce environmentally friendly compounds including the volatile organic compounds (VOCs) which can be used as biofumigants.Methods: Different Streptomyces species (n=15) previously isolated from the guts of termites and stored in the University of the Sunshine Coast’sMicrobial Library were tested for their antifungal VOCs against Pyrrhoderma noxium.Results: Fourteen of them were found to display inhibition (39.39-100%) to the mycelial development of the pathogen. Strongest antifungal activity displaying isolates USC-592, USC-595, USC-6910 and USC-6928 against the pathogen were selected for further investigations. Their VOCs were also found to have plant growth promotional activity observed for Arabidopsis thaliana with an increase of root length (22-36%) and shoot length (26-57%). The chlorophyll content of the test plant had a slight increase of 11.8% as well. Identified VOCs included geosmin, 2-methylisoborneol, 2-methylbutyrate, methylene cyclopentane, β-pinene, dimethyl disulfide, ethyl isovalerate, methoxyphenyl-oxime and α-pinene. Additionally, all 15 Streptomyces isolates were found to produce siderophores and indole acetic acid as well as the enzyme chitinase which is known to break down the fungal cell wall.Discussion: Findings indicate that termite gut-associated streptomycetes might be used to control Pyrrhoderma noxium by utilizing their wide range of inhibitory mechanisms.

Plant fungal pathogen Pyrrhoderma noxium is responsible for the destructive and invasive disease of brown root rot currently affecting the city of Brisbane, Australia. In order to address this issue, environmentally friendly and safe alternatives to chemical control are preferred due to the city’s public setting. Antifungal natural products are ideal candidates as biological control alternatives and can be detected through investigating the metabolomes of microbial symbionts. Within this study, an NMR-based metabolomics approach was applied to fermentation extracts obtained from 15 termite gut-associated streptomycetes. By analysing the NMR spectra, six of the extracts which displayed similar chemical profiles exhibited antifungal activity against the P. noxium pathogen. The major compound within these extracts was identified as acetomycin using NMR and X-ray crystallography analyses. This is the first reporting of acetomycin as a potential natural product fungicide, particularly as an antifungal agent against P. noxium. Inhibitory activity was also found against other important fungal crop pathogens, including Aspergillus niger, Botrytis cinerea, and Alteranaria alternata. Further experimentation using a woodblock test found inhibitory activity on the growth of the P. noxium pathogen for up to 3 weeks and a significant difference in the integrity of the woodblocks when conducting compression strength tests after 6 weeks. Therefore, acetomycin may be used as a biological control agent and natural product fungicide against P. noxium.