Spatial Gene Expression in Fungi: mRNA Localization, Condensates, and Beyond

ABSTRACT Polarized growth and cellular asymmetry are broadly conserved properties of fungal life, from transient bud‐site selection in unicellular yeasts to sustained hyphal extension in filamentous and coenocytic species. While vesicle trafficking, cytoskeletal organization, and cell‐wall remodeling are well‐established contributors to these processes, the role of mRNA localization is only beginning to be fully appreciated. In this review, we examine how the spatial regulation of mRNAs and their translation contributes to fungal polarity, morphogenesis, and environmental adaptation. We discuss current knowledge around three interconnected layers contributing to mRNA localization: active cytoskeletal transport—actin‐based in compact yeasts and microtubule‐based in long hyphae; partitioning into biomolecular condensates such as P‐bodies and Whi3–mRNA assemblies; and cytoplasmic‐scale architectural features including bulk flow, nuclear positioning, and nuclear heterogeneity that become increasingly important in multinucleate and coenocytic systems such as arbuscular mycorrhizal fungi. Together, these mechanisms establish spatial gene expression as an integral component of fungal polarity, with implications for fungal development, host–pathogen interactions, and ecological adaptation, and for our broader understanding of polarized growth in eukaryotic cell organization.