Exopolysaccharides (EPSs) are sugar-based polymers that are synthesized and secreted by many microorganisms. Microbial EPSs play important roles in the establishment of symbiotic and pathogenic relationships with their hosts. For example, in the legume-rhizobia symbiosis, the recognition of compatible rhizobial EPSs is essential for root nodule symbiosis (RNS). During her PhD studies, Sha Zhang has investigated the roles of bacterial EPS in the establishment of root-associated microbiota. She performed genome mining for commensal bacteria associated with Lotus japonicus, and identified bacterial genes predicted to be involved in EPS production. Based on this information, she conducted a series of studies using microbial communities of increasing complexity to characterize the role of plant exopolysaccharide receptors and the impact of bacterial EPS on root-associated microbiota assembly. These studies provide a new perspective on the role of EPS signalling in modulating bacterial root and rhizosphere colonization.

The PhD study was completed at the Science Park, Department of Molecular Biology and Genetics, Aarhus University.

This summary was prepared by the PhD student.

Time: Thursday, 24 February 2022 at 13:00 pm

Place: The PhD defence will be held online

Title of PhD thesis: EPS signalling plays important roles in shaping root microbiota assembly of Lotus japonicus

Contact information: Sha Zhang, e-mail: zhangsha@mbg.au.dk, tel.: +45 52 68 84 05

Members of the assessment committee:

Associate Professor Davide Bulgarelli, Department of Plant Sciences, University of Dundee, UK

Associate Professor Mette Haubjerg Nicolaisen, Department of Plant and Environmental Sciences, University of Copenhagen, Denmark

Associate Professor Knud Erik Larsen, Department of Molecular Biology and Genetics, Aarhus University (chair)

Main supervisor:
Associate Professor Simona Radutoiu, Department of Molecular Biology and Genetics, Aarhus University, Denmark

Co-supervisor:
Professor Jens Stougaard, Department of Molecular Biology and Genetics, Aarhus University, Denmark

Language: The PhD dissertation will be defended in English

The defence is public.

The PhD thesis will be made available for reading at the Graduate School of Natural Sciences/GSNS, Katrinebjergvej 89F, building 5132, 8200 Aarhus N