Brown root-rot disease, caused by the phytopathogenic fungus Pyrrrhoderma noxium, has caused significant damage to various tree species in Brisbane, Australia. The disease is characterised by the decay of roots and lower stem tissues, leading to the collapse and death of the infected trees. Concerns centred around the loss of many culturally-significant trees, such as the Moreton Bay Fig trees found in many of the city’s parks, has prompted the need to address this issue. Past control methods involved the use of chemical fungicides, which may not be sustainable in the long term due to their detrimental effects. As an alternative, this study aims to investigate the use of biological control methods using microorganisms and their antifungal metabolites. Actinomycetes are Gram-positive bacteria that are known to produce a majority of commercially available secondary metabolites, including antibiotics and antifungal compounds. Additionally, insects, such as Termites, living in unique niches often facilitate microbial symbionts with specialised biological activities. Actinomycetes have been found amongst the most dominant within the Termite’s microflora and therefore, may produce novel metabolites to protect the termite host from invading fungal pathogens.
A joint study between the University of the Sunshine Coast (UniSC) and the Brisbane City Council (BCC) is being conducted to assess the efficacy of biological control agents to control the spread of this disease. The study focuses on the use of termite gut-associated actinomycetes, which might offer a relatively unexplored resource for the discovery of valuable bioactive products. These bacteria have also shown potential in controlling various fungal plant diseases.
The aim of this study is to characterise termite gut-associated actinomycetes and evaluate their potential as biological control agents against Pyrrrhoderma noxium-induced brown root-rot disease. The findings of this study can contribute to the development of a sustainable and eco-friendly biocontrol method for the causative agent of this destructive disease.