3 Hyphal Tip Growth in Filamentous Fungi

Hyphae of filamentous fungi extend at the apex by a polarized mechanism that involves the highly ordered and regulated delivery of secretory vesicles. In Dikarya fungi these tip-directed vesicles accumulate temporarily at the Spitzenkorper (Spk) before being delivered to the apical plasma membrane, where they provide the machinery needed for cell wall synthesis. The organizational complexity of the Spk is known only in a few fungal taxa. Yet, it is still unclear whether the structural differences found are correlated with a specific function. Hyphal tip growth requires, in addition, the precise positioning and coordinated interactions of cytoskeleton components and key secretory organelles needed to sustain the continuous process of hyphal elongation.