Directions: Clearly and concisely answer the questions below.
1. What are the mycosymbionts of fungi?
2. Distinguish between necrotrophic and biotrophic microsymbionts with examples.
3. Distinguish between mycophycobiosis and lichen.
1. Mycosymbionts of fungi are organisms that form a mutually beneficial relationship with fungi. These can include bacteria, other fungi, algae, or plants.
2. Necrotrophic microsymbionts are organisms that rely on dead or dying host tissues for their nutrition. They derive nutrients from decomposing organic matter and often cause disease in their hosts. Examples of necrotrophic microsymbionts include certain fungal pathogens like Botrytis cinerea, which causes gray mold in plants.
Biotrophic microsymbionts, on the other hand, establish a relationship where they derive nutrients from living host tissues without causing significant harm. They often form intimate associations with their hosts and can have specialized structures for nutrient exchange. An example of a biotrophic microsymbiont is the arbuscular mycorrhizal fungi, which form mutualistic relationships with the roots of most plants.
3. Mycophycobiosis is a term used to describe a symbiotic relationship between a fungus and a photosynthetic organism, often a green alga or cyanobacterium. In this mutualistic association, the fungus provides a protected environment for the photosynthetic partner, while the partner supplies the fungus with organic compounds produced through photosynthesis.
Lichen, on the other hand, refers to a composite organism that arises from the symbiotic relationship between a fungus and a photosynthetic partner, which can be either an alga or cyanobacterium. Lichens are unique in that they have a morphologically distinct thallus, which is the body of the lichen formed by the intertwined hyphae of the fungus and the photosynthetic partner. The fungus provides a protective structure, while the photosynthetic partner provides nutrients through photosynthesis. Lichens are found in diverse habitats and have ecological importance as pioneer organisms in harsh environments.