From glycans to green biotechnology: exploring cell wall dynamics and phytobiota impact in plant glycopathology.

Filamentous plant pathogens, including fungi and oomycetes, pose significant threats to cultivated crops, impacting agricultural productivity, quality and sustainability. Traditionally, disease control heavily relied on fungicides, but concerns about their negative impacts motivated stakeholders and government agencies to seek alternative solutions. Biocontrol agents (BCAs) have been developed as promising alternatives to minimize fungicide use. However, BCAs often exhibit inconsistent performances, undermining their efficacy as plant protection alternatives. The eukaryotic cell wall of plants and filamentous pathogens contributes significantly to their interaction with the environment and competitors. This highly adaptable and modular carbohydrate armor serves as the primary interface for communication, and the intricate interplay within this compartment is often mediated by carbohydrate-active enzymes (CAZymes) responsible for cell wall degradation and remodeling. These processes play a crucial role in the pathogenesis of plant diseases and contribute significantly to establishing both beneficial and detrimental microbiota. This review explores the interplay between cell wall dynamics and glycan interactions in the phytobiome scenario, providing holistic insights for efficiently exploiting microbial traits potentially involved in plant disease mitigation. Within this framework, the incorporation of glycobiology-related functional traits into the resident phytobiome can significantly enhance the plant's resilience to biotic stresses. Therefore, in the rational engineering of future beneficial consortia, it is imperative to recognize and leverage the understanding of cell wall interactions and the role of the glycome as an essential tool for the effective management of plant diseases.