21st Century Guidebook to Fungi

Events at the hyphal tip are crucial to the extension of the hypha; so it is vital that we describe the molecular processes taking place in the hyphal tip as far as we can, and this is the main purpose of Chapter 5.

In this chapter we will give you a complete outline of eukaryotic cell biology with emphasis on how fungal cells work and how the cell biology contributes to mycelial growth. Because they are eukaryotes that are easy to cultivate in the laboratory, several fungi have been adopted as model organisms for experimentation and we will show how yeasts, in particular, have been used in this way since the nineteenth century. We discuss the essentials of cell structure in some detail, emphasising the molecular biology of the nucleus, nucleolus, nuclear import and export, and mRNA translation and protein sorting. We also briefly cover nuclear genetics and mitotic and meiotic nuclear division. The plasma membrane and signalling pathways, and endomembrane systems, cytoskeletal systems and molecular motors form major topics because directed and rapid transport of materials needed for hyphal tip extension is a crucial and characteristic feature of highly polarised filamentous growth. Other features of cell biology that are specific to fungi include the fungal cell wall, the cell biology of the hyphal apex, the nature of hyphal fusions and mycelial interconnections, the meaning of cytokinesis in fungi, and septation and the yeast–mycelial dimorphism.