Endosymbiotic Origin & Host-Microbe Interactions

Walter began his academic research journey in 2017, focusing on the molecular mechanisms underlying host–microbe interactions, particularly plant–microbe symbiosis. In 2018, he and his colleagues developed an engineered endophyte-assisted system for in planta dioxin bioremediation, using non-pathogenic microorganisms living within plant tissues to facilitate the removal of environmental pollutants. This work was awarded a Gold Medal at the International Genetically Engineered Machine (iGEM) Competition and was subsequently published as a journal article.

During his Bachelor's (2017–2021) and Master's (2021–2023) studies, Walter investigated how bacterial endophytes promote plant growth and enhance tolerance to environmental stresses, with a particular focus on bacterial metabolites that influence plant respiration and photosynthesis. Alongside this work, he contributed to research into early energy metabolism and the origins of life, particularly the manipulation of cellular carbon fluxes. These experiences sparked his interest in the molecular and metabolic communication between microbial symbionts and host organelles, especially mitochondria and chloroplasts.

To explore these questions further, Walter joined Academia Sinica, Taiwan, where he developed expertise in plant organelle membrane protein topology, symbiont evolutionary and comparative genomics, and multi-omics approaches. Between 2023 and 2024, he and his collaborators used both plant (Arabidopsis thaliana and its bacterial endophytes) and animal (Acropora corals and their bacterial symbionts) model systems to investigate metabolic crosstalk between symbiotic bacteria and their hosts, particularly at the organelle level. By combining multi-omics analyses with experimental approaches, Walter sought to understand how metabolic interactions in present-day symbiotic systems might offer insights into the evolution of cellular energy metabolism and the origins of endosymbiosis.

From 2024 to 2026, Walter worked as a Predoctoral Researcher in Prof Saskia Hogenhout Group at the John Innes Centre, UK, where he expanded his research into effector biology and molecular plant-microbe-nsect interactions. His work focused on the functional characterisation of a chloroplast-targeted phytoplasma effector that promotes plant growth, investigating how pathogen-derived effectors manipulate host metabolism, chloroplast function and plant development. This research further developed his interest in the links between organelle metabolism, plant growth and host-microbe interactions, whilst exploring how a better understanding of phytoplasma effectors might inform future approaches to plant disease management and crop improvement.

Building on his interdisciplinary background in molecular plant-microbe interactions, organelle biology, metabolic regulation, evolutionary genomics and effector biology, Walter's current research explores how chloroplasts influence leaf development during the evolutionary transition from C3 to C4 photosynthesis. His broader interests lie in the molecular and metabolic interactions between hosts, microbial symbionts and cellular organelles, particularly chloroplasts and mitochondria, as well as the evolutionary origins of endosymbiosis. Walter is also keen to translate fundamental research into practical applications. By bringing together insights from plant–microbe interactions, organelle function and developmental biology, he hopes to contribute to our understanding of plant evolution and identify new approaches to improving plant health, photosynthetic efficiency and crop productivity.

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