Relationship Between Fungi And Friends

Plants and Fungi: friends or foe?

The relationship between plant and fungi, whether friend or foe, is absolutely essential to countless processes on earth. Symbiosis refers to an ecological relationship between organisms of two different species that live together in direct and intimate contact (Campbell, 10th Edition, Glossary, Reece et. al). Fungi who are in symbiotic association with a host plant can either be facultative symbionts, which means they are either free-living saprotrophs or live within the plant. Other Fungi are obligate symbionts and they grow exclusively in association with living plants (The Fungi, Carlile et. al). Central to the carbon economy is mutualism, which is a symbiotic relationship in which both the fungus (e.g.

al). Thus, it is quite clear that plants and fungi can be hailed as friends, not just foes. Mycorrhizal fungi are undoubtedly the key players in this type of “friendly” symbiosis. Fossil and molecular evidence from primitive land plants illustrate that mycorrhizas (“fungus-roots” (Mycorrhizal Fungi: The ties that bind, Read) most certainly co-evolved with plant roots (Mycorrhizal fungi: the ties that bind, Read). This fungal group have long and intricate mycelial networks which can act alongside the plant roots (Campbell, p638). This improves the uptake of minerals e.g. phosphate, from the soil to the plant, as the mycelial networks are more proficient (Campbell, p638). However, this is symbiotic mutualism, so the plant predictably returns the favour by providing organic molecules such as carbohydrates to the fungi (Campbell, p638).

Many species of mutualistic endophytic fungi including Clavicipitaceae Ascomycetes (Fungal endophytes of grasses: a defensive mutualism between plants and fungi, Clay) have the potential to provide their host plant with improved growth, tolerance to drought and resistance to disease (Fungal Symbioses from mutualism to parasitism: who controls the outcome, host or invader?, Redman et.