Oral Presentation Australian Microbial Ecology 2017

Transcriptionally active wheat rhizosphere microbiomes in fields suppressive and non-suppressive for Rhizoctonia solani AG 8 (#19)

Helen Hayden 1 , Keith Savin 1 , Jenny Wadeson 1 , Pauline Mele 1
  1. Department of Economic Development, Jobs, Transport and Resources, BUNDOORA, VIC, Australia

Rhizoctonia root rot and bare patch disease, caused by the soilborne fungus Rhizoctonia solani anastomosis group (AG) 8, results in patches of stunted plants with reduced grain production, causing losses of $77 million per annum in cereal cropping in Australia. In the absence of resistant cultivars of wheat or barley and a wide host range current control measures are limited. A sustainable and enduring method for disease control is needed and may lie in the enhancement of biological disease suppression, where the resident microbial community counteracts the pathogen and inhibits it from infecting the plant. The mechanism of disease suppression is not known for this pathosystem however there is evidence of effective biological control of R. solani at our study site in Avon, South Australia. The aim of this research is to find functional biomarkers which may be used to identify fields with disease suppression, and measure the impacts of different farm management practices on disease suppression. A metatranscriptomic approach was applied to assess the taxonomic and functional characteristics of the rhizosphere microbiome of wheat plants grown in adjacent fields which are suppressive and non-suppressive for Rhizoctonia solani AG 8. Disease suppressive soils had a unique microbial community according to their gene expression profiles. Microbial mRNA genes from twelve rhizosphere samples were mapped to metabolic databases (KEGG, COG, SEED) to infer differentially expressed microbial functions in suppressive and non-suppressive rhizosphere soils. These differentially expressed genes provide a focus for future studies to determine precisely the molecular interplay of plant-microbe-pathogen interactions with the ultimate goal of the development of a beneficial rhizosphere microflora to reduce R. solani AG 8 infection of crops.