Poster
Kerstin Unger
Friedrich Schiller University Jena
Jena, Thuringen, Germany
Marco Mauri
Friedrich Schiller University Jena
Jena, Thuringen, Germany
Michael Reichelt
Max Planck Institute for Chemical Ecology
Jena, Thuringen, Germany
Jonathan Gershenzon
Director
Max Planck Institute for Chemical Ecology
Jena, Thuringen, Germany
Rosalind Allen
Friedrich Schiller University Jena
Jena, Thuringen, Germany
Matthew Agler
Friedrich Schiller University Jena
Jena, Thuringen, Germany
Healthy leaves host both commensal and opportunistic pathogenic bacteria whose interactions help mediate microbiome balance. To eventually control this balance by biocontrol agents, it is important to understand the drivers of interactions. Isothiocyanates (ITCs) are glucosinolate degradation products in Arabidopsis thaliana that are toxic to most bacteria, but they can be detoxified by the ITC hydrolase SaxA. We hypothesized that the SaxA-mediated degradation of 4-methylsulfinylbutyl ITC (4MSOB-ITC) by the opportunistic pathogen Pseudomonas viridiflava 3D9 (Ps) functions as a public good by protecting co-colonizing commensals. This is important, because commensals would compete with Ps for resources, preventing it from causing disease. Five bacterial commensals isolated along with Ps from healthy A. thaliana leaves were characterized for their response to 4MSOB-ITC and growth with or without Ps or a PsΔsaxA mutant. We use generalized consumer-resource models incorporating ITC toxicity, substrate utilization and ITC degradation to predict coculture growth. A rescue index based on the models illustrates under which conditions SaxA functions as a public good. By varying degrader:commensal ratios in silico we aim to define an optimal commensal community which benefits from SaxA-mediated ITC degradation while keeping the pathogen on low levels to suppress disease. This may help to understand how balance in the leaf microbiome arises.