Patricia obtained her Master’s degree in Molecular Biotechnology at the Technical University of Munich. During her Master thesis she studied the role of endogenous plant signaling peptides on plant immunity; in particular, endogenous peptides that regulate immune signaling as well as growth and developmental processes. She is interested in plant-fungal interactions and the molecular mechanisms that allow colonization by beneficial fungal endophytes. The primary objective of her PhD is to dissect different cell death pathways involved in the accommodation of root-associated microbes.

Autophagy restricts fungal accommodation in the roots of Arabidopsis thaliana

Serendipita indica (syn. Piriformospora indica) is a mutualistic root symbiont capable of colonizing root epidermal and cortex cells through a biphasic strategy in various plant hosts, including the model plant Arabidopsis thaliana. Colonization by S. indica is characterized by an early biotrophic phase followed by a controlled host cell death-associated phase (Deshmukh et al., 2006; Zuccaro et al., 2011; Qiang et al., 2012; Lahrmann et al., 2013).

The mechanism of regulated cell death is crucial for proper fungal accommodation. However, the host molecular mechanisms that restrict S. indica colonization and enable the maintenance of a mutualistic relationship are largely unknown. Fungal colonization triggers a metabolic reprogramming of the host tissue, promoting the activation of pathways aimed at restoring homeostasis and limiting cell death. One potential contributing mechanism to the establishment of this beneficial interaction is autophagy. Autophagy is a major degradation and nutrient recycling pathway in eukaryotes that plays a vital role in maintaining cellular homeostasis.

This project examines the potential involvement of autophagy in the colonization of S. indica and cell death mediated by deoxyadenosine (dAdo), a cell death inducer produced by two S. indica secreted enzymes during colonization. Our findings reveal that this mechanism plays a crucial role in restricting colonization and provides protection against dAdo-induced cell death, suggesting a pro-survival function of autophagy (Zecua et al., 2023). We propose that autophagy serves as a key component in the host metabolic checkpoint, coordinating external signals and host defenses to finely regulate the accommodation of beneficial fungi. The impact of nutrient availability on this regulation is an important aspect that is currently under investigation.