Metabolic reprogramming landscape orchestrating chlamydospore formation in Volvariella volvacea

Chlamydospore formation in the edible mushroom Volvariella volvacea is crucial for its stress tolerance and survival, but its underlying molecular and structural regulatory mechanisms remain largely elusive compared with model fungi. This lack of knowledge hinders efforts to improve stress resistance and advance molecular breeding in this economically important species. To address this, we conducted an integrated analysis combining morphological, ultrastructural, genomic, and transcriptomic approaches across 4 key developmental stages. Our results delineate a clear developmental trajectory of chlamydospore formation: from hyphal swelling to primordium formation, and finally to maturation with a reinforced cell wall. We show that this process is driven by the coordinated activation of storage compound biosynthesis, a shift in energy metabolism, and functional modification of the cell wall. Furthermore, two conserved Velvet family genes, VvVel1 and VvLaeA, act as putative regulators with stage-specific expression patterns. Together, these findings establish a comprehensive metabolic and regulatory framework for chlamydospore development in V. volvacea and offer a theoretical basis for stress-resistance breeding.