Chitin Metabolism In Fungi

Abstract

The fungal kingdom is very diverse, with species growing as unicellular yeasts to branching hyphae. Developing an outer protective layer, namely the cell wall, is critical for growth and survival of the fungal cell in the diverse environments where fungi live. The shape and integrity of the fungus is dependent upon the mechanical strength of the cell wall, which performs a wide range of essential roles during the interaction of the fungus with its environment. The wall composition frequently varies markedly between different species of fungi (Adams, 2004). The fungal cell wall is a complex structure composed of chitin, glucans and other polymers, and there is evidence of extensive cross- linking between these components. The complexity of the cell wall means that its biogenesis demands a significant number of cellular activities that have to act in concert with the essential functions controlling cell growth and morphogenesis, since the wall determines cell shape. Furthermore, the wall is a highly dynamic structure subject to constant change, for example, during cell expansion and division in yeasts, and during spore germination, hyphal branching and septum formation in filamentous fungi. Cell wall polymer branching, cross-linking, and the maintenance of wall plasticity during morphogenesis, may depend upon the activities of a range of hydrolytic enzymes found intimately associated with the fungal cell wall (Dahiya, 2007).