Copper fungicides, which are still widely used due to a lack of efficient alternatives, need to be urgently replaced because of their unfavourable profile. There is consensus that several new sustainable alternatives need to be developed and brought to the market to reach the goal of organic farming without copper. This project aims to identify new microbial strains with a protective effect against important foliar diseases which are currently controlled with copper fungicides. We focus on strains producing antimicrobial metabolites or inducing plant immune responses, considering both the use of living microbial strains as well as their metabolites. To identify promising candidates, we are exploring the microbiome of disease-suppressive compost extracts, which are known to contain a plethora of mostly unexplored microorganisms.
Within the greater context of this project, we offer the following master thesis:
Investigating the antifungal activity of microbial strains isolated from disease-suppressive composts
A collection of microbial strains associated with disease-suppressive composts will be screened for their protective potential against foliar diseases. Candidate strains and their culture filtrates will be evaluated for in vitro antifungal activity using 96-well plate assays. Promising strains will subsequently be assessed for direct antifungal activity and their ability to induce plant immunity in established plant-pathogen systems (Grapevine – Plasmopora viticola and tomato – Alternaria solani). To investigate induced resistance, plant immune responses will be quantified by qPCR analysis of defence-related marker genes in grapevine and/or tomato. To further understand underlying mechanisms, Arabidopsis thaliana immune-signalling mutants may be employed. Additional techniques may include genome sequencing of selected strains and microscopy to characterize plant-microbial interactions.
Barbara Thürig
Fiona Fitchett
To be determined
