Poster Presentation Australian Microbial Ecology 2019

Application of plant-immune biosensors for screening and discovery of Actinobacteria biocontrol candidates against necrotrophic fungal pathogens  (#144)

Katharina Belt 1 , Cindy A Myers 1 , Karam Singh 1 , Margaret Roper 1 , Cathryn O'Sullivan 2 , Yit-Heng Chooi 3 , Louise Thatcher 1
  1. CSIRO, Floreat, WA, Australia
  2. CSIRO, Melbourne, Victoria, Australia
  3. UWA, Crawley, WA, Australia

Actinobacteria present a phylum of gram-positive bacteria, which can be terrestrial or aquatic. They form an essential part in our economics as agriculture and forests depend on their contribution to the soil system. They are of great interest as these bacteria can be applied in agriculture as plant growth promoting agents as well as in industry for their production of natural bioactive metabolites such as antibiotics and pathogen inhibiting compounds. Plant beneficial isolates are able to inhabit the plant root system without causing a disease and some are able to prime a plants immune response against certain pathogens. They are largely influenced by their surroundings where abiotic and biotic factors have impact on their metabolite production.

We have a collection of Actinobacteria isolated from south-west Western Australia. Our goal is to identify isolates that can prime a plants’ immune response with potential to provide protection against a broad range of phytopathogens, but with a focus on protection against economically destructive necrotrophic fungal pathogens. This will be achieved through a novel approach, non-destructively capturing visible plant immune-biosensor output (gene-based reporter systems) in real-time following inoculation with potential Actinobacteria biocontrol agents to identify isolates with novel plant immunity inducing properties. This way, plant microbe interactions can be monitored and involvement of Actinobacteria in plant defense signalling pathways can be determined. In combination, the Actinobacteria isolates are assessed for production of biocontrol compounds (e.g. antifungals) via routine in vitro pathogen growth inhibition assays. Using a combination of omics-guided approaches (genomics, transcriptomics, metabolomics), we aim to identify, extract and purify these compounds, and develop a biocontrol fungicide for agricultural disease control. In order to increase metabolite production in the selected Actinobacteria isolates, different culture conditions are being used to identify the optimal environment. By combining immune biosensor screening together with antifungal bioactivity assays, strong Actinobacteria strains can be selected with the potential of improving pest management for our agriculture.