Mapping microhabitats of lignocellulose decomposition by a microbial consortium
Marija Veličković, Ruonan Wu, Yuqian Gao, Margaret W. Thairu, Dušan Veličković, Nathalie Munoz Munoz, Chaevien Clendinen, Aivett Bilbao Pena, Rosalie Chu, Priscila M. Lalli, Kevin Zemaitis, Carrie Nicora, Jennifer Kyle, Danny Orton, Sarai Williams, Ying Zhu, Rui Zhao, Matthew Monroe, Ronald Moore, Bobbie‐Jo Webb‐Robertson, Lisa Bramer, Cameron R. Currie, Paul Piehowski, Kristin Burnum-Johnson
Abstract
The leaf-cutter ant fungal garden ecosystem is a naturally evolved model system for efficient plant biomass degradation. Degradation processes mediated by the symbiotic fungus Leucoagaricus gongylophorus are difficult to characterize due to dynamic metabolisms and spatial complexity of the system. Herein, we performed microscale imaging across 12-µm-thick adjacent sections of Atta cephalotes fungal gardens and applied a metabolome-informed proteome imaging approach to map lignin degradation. This approach combines two spatial multiomics mass spectrometry modalities that enabled us to visualize colocalized metabolites and proteins across and through the fungal garden. Spatially profiled metabolites revealed an accumulation of lignin-related products, outlining morphologically unique lignin microhabitats. Metaproteomic analyses of these microhabitats revealed carbohydrate-degrading enzymes, indicating a prominent fungal role in lignocellulose decomposition. Integration of metabolome-informed proteome imaging data provides a comprehensive view of underlying biological pathways to inform our understanding of metabolic fungal pathways in plant matter degradation within the micrometer-scale environment.