ABSTRACT
Knowledge of fungal biology is still poorly integrated into general ecology theory. Fungal mycelia play a pivotal role in many ecosystem processes, but a better understanding of the ways in which they shape plant communities and ecosystems will not be possible without an improved understanding of the spatial organization of fungal mycelia, including microscale interactions with substrates and other organisms. Fungal mycelia interact with and modify their environment at a range of spatial scales, influencing microscale interactions between cells and molecules, meso-and macroscale effects on organisms and growth substrates, and ultimately whole plant communities and ecosystems. Hyphal tips of fungi produce a wide spectrum of molecules, including organic acids, polysaccharides, hydrophobins, antibiotics, siderophores, and enzymes. These molecules have a diverse array of functions and mediate cellular recognition, morphogenesis, antibiosis, pathogenesis, stress tolerance, degradation, and nutrient mobilization, as well as symbiotic associations. Abundant release of lytic enzymes into the environment is a central ability of fungi that they share with various prokaryotes, but which distinguishes them from other eukaryotic organisms. During evolution, fungi have tended to live as endobionts of other organisms in parasitic or mutualistic relationships. In mycorrhizal symbiosis, these two fungal characteristics may interact to enable the plant hosts to benefit from the superior ability of their fungal associates to mobilize nutrients from complex, organic substrates.
