Biogenesis of macrofungal sclerotia: influencing factors and molecular mechanisms

Sclerotia are dense, hard tissue structures formed by asexual reproduction of fungal hyphae in adverse environmental conditions. Macrofungal sclerotia are used in medicinal materials, healthcare foods, and nutritional supplements because of their nutritional value and biologically active ingredients, which are attracting increasing attention. Over the past few decades, the influence of abiotic factors such as nutrition (e.g., carbon and nitrogen sources) and environmental conditions (e.g., temperature, pH), and of the local biotic community (e.g., concomitants) on the formation of macrofungal sclerotia has been studied. The molecular mechanisms controlling macrofungal sclerotia formation, including oxidative stress (reactive oxygen species), signal transduction (Ca²⁺ channels and mitogen-activated protein kinase pathways), and gene expression regulation (differential expression of important enzyme or structural protein genes), have also been revealed. At the end of this review, future research prospects in the field of biogenesis of macrofungal sclerotia are discussed. KEY POINTS: • We describe factors that influence biogenesis of macrofungal sclerotia. • We explain molecular mechanisms of sclerotial biogenesis. • We discuss future directions of study of macrofungal sclerotia biogenesis.