The endophytic microbiota is a community of various microorganisms that reside in plant tissue. These microbes are known to promote plant health and resilience, and their members do not simply exist side by side. Instead, they constantly interact with each other and with their host, forming a complex network of relationships. The association can be so close that the absence of key members can significantly impair the plant’s resilience and even its viability. The ultimate goal of this thesis is to study the whole microbial community directly in plant tissue and to investigate how they interact with their host at the ultrastructural level using cryo-electron microscopy (cryo-EM).
First, I examined the morphology of Chitinophaga pinensis, a potential key member of the plant microbiota. This revealed remarkable morphological plasticity, raising two questions: whether it represents an adaptation to a host-associated lifestyle and to what extent it may be linked to the...
Show moreThe endophytic microbiota is a community of various microorganisms that reside in plant tissue. These microbes are known to promote plant health and resilience, and their members do not simply exist side by side. Instead, they constantly interact with each other and with their host, forming a complex network of relationships. The association can be so close that the absence of key members can significantly impair the plant’s resilience and even its viability. The ultimate goal of this thesis is to study the whole microbial community directly in plant tissue and to investigate how they interact with their host at the ultrastructural level using cryo-electron microscopy (cryo-EM).
First, I examined the morphology of Chitinophaga pinensis, a potential key member of the plant microbiota. This revealed remarkable morphological plasticity, raising two questions: whether it represents an adaptation to a host-associated lifestyle and to what extent it may be linked to the presence of bacteriophages. In this context, a widespread presence of prophages within members of endophytic Bacteroidota was found. In addition, new workflows were developed specifically to make large-volume samples from hyphal networks of arbuscular mycorrhizal fungi and plant tissues, accessible for cryo-EM. These included the introduction of snap-button planchettes and the use of fluorescence-guided targeting during lamella preparation.
Overall, this work introduces new cryo-EM techniques that enable the study of plant–microbiota interactions directly in plant tissue at the ultrastructural level and provide a foundation for future research.
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