The world of hyphae

This article describes the hyphal features that have allowed fungi to conquer nature so extensively and so ubiquitously. Fungi became champions of nutrition via absorption by developing hyphae with an efficient growth mechanism that combined rapid cell wall construction with secretion of digestive enzymes. Hyphae are long cylindrical cells growing at one end, the apex. Their cell walls are made by the combination of microfibrillar polymers (usually chitin) embedded in amorphous polysaccharides (usually β-1,3 glucans). Their high growth rate is supported by an efficient vesiclebased secretory apparatus, whose ultimate goal is to maintain a rapid flow of cell-wall building materials and digestive enzymes to the hyphal apex. The unique hyphoid morphology of a hypha can be described by a simple mathematic equation generated by a moving supply center emitting wall-building vesicles in all directions. The Spitzenkörper is proposed to function as a vesicle supply center that generates the characteristic cell wall of a hypha and also guides hyphal growth direction. Fungal organisms with completely different evolutionary origins, the cellulosic Oomycetes and the more numerous chitinous fungi, both develop hyphae and mycelia to insure efficient growth. Hyphae are thus the basis for the success of fungi in Nature.