Question

22. List some of the ecological roles of fungi.

1. What are mycorrhizae? Differentiate between endomycorrhizae and ectomycorrhizae.
2. Define lichen. What are the three types?
3. Describe at least 2 fungal parasite or pathogen of plants.
4. Describe at least three fungal pathogens of humans.
5. Provide examples of how fungi directly benefits humans.

Answer 1

a) Endo mycorrhizae and Ectomycorrhizae.

Mycorrhizae virtually interpret to “fungus-root".Mycorrhizae a fungus that grows during association with the roots of a plant in a symbiotic or gently pathogenic relationship.

In several plants, mycorrhiza is fungi that grow within the plant’s roots, or on the surfaces of the roots. The plant and also the plant have a mutualist relationship, wherever the fungus facilitates water and nutrient uptake within the plant, and also the plant provides food and nutrients created by photosynthesis to the fungus. This exchange may be vital to consider nutrient cycles and also the ecology, evolution, and physiology of plants.

There are 2 sorts of mycorrhizae: ectomycorrhizae, and endo mycorrhizae.

Ectomycorrhiza

Ectomycorrhiza tends to create mutual symbiotic relationships with woody plants, together with birch, beech, willow, pine, oak, spruce, and fir. Ectomycorrhizal relationships are characterized by an intercellular surface referred to as the Hartig net. The Hartig net consists of extremely branched hyphae connecting the epidermic and cortical root cells. in addition, ectomycorrhiza is known by the formation of a dense hyphal sheath close to the root’s surface. this can be referred to as the mantle. In alternative words, ectomycorrhiza lives solely on the surface of the root. Overall, solely 5-10% of terrestrial plant species have ectomycorrhiza.

Endomycorrhiza

On the opposite hand, endomycorrhizal are found in over eightieth of extant plant species -including crops and greenhouse plants like most vegetables, grasses, flowers, and fruit trees. Endomycorrhizal relationships are characterized by penetration of the cortical cells by the fungi and also the formation of arbuscular and vesicles by the fungi. In alternative words, endomycorrhiza has an exchange mechanism on the within of the root, with the fungi’s hyphae extending outside of the root. it's an additional invasive relationship compared to it of the ectomycorrhiza.

b) Lichen

Lichens are compound plants as alga and fungi live along in close association, as a result of that each is benefited. This relationship is named symbiosis. They occur as greyish green growths on rocks, the bark of the tree, or on the bottom.

There are 3 main sorts of lichens:

foliose - foliose lichens have 2 simply distinguishable sides. In alternative words, there's a top side and there's a bottom side. they will be terribly flat, leaflike like lettuce, or convoluted and full of ridges and bumps.

fruticose- Fruticose lichens are pendant and hair-like, upright and shrubby, or upright and cup-like. several fruticulose lichens have spherical branches that have a central core are hollow within the middle. alternative fruticose lichens have flat branches that tangle up with are.

crustose - crustose lichens are simply that, crusts. They form a crust over a surface, like a boulder, the soil, a car, or your roof shingles. they will come in several bright, spirited colors like sunny yellow, orange, and red, in addition to grays and greens. crustose lichens are pressed against their substrate

c) 2 fungal parasite or pathogen of plants

Plant pathogenic fungi cause terribly vital economic losses to crops in each temperate and tropical agricultural and forestry systems. They additionally occur in natural systems and play a task in mediating plant community structure, though relatively very little is understood regarding the extent of such regulation.

Soil-borne plant pathogens occur across all fungal taxonomic groups and vary in their host specificity; vital examples embody Gaeumannomyces graminis (take-all of wheat), Rhizoctonia solani (root and stem rots, including potato tubers, with a good host range), Pythium spp. (damping-off), armillaria mellea (honey fungus, with a good host, vary of trees), Fusarium oxysporum (a wide variety of forms, that have an effect on specific plants – e.g., F. cubense causes wilt in a banana).

d) Three fungal pathogens of humans.

Pathogenic fungi are fungi that cause disease in humans or different organisms

Candida species cause infections in people with deficient immune systems. Th1-type cell-mediated immunity (CMI) is needed for the clearance of a fungal infection. Candida albicans may be a kind of diploid yeast that normally happens among the human gut microflora. C. Albicans is an opportunist infective agent in humans. Abnormal overgrowth of this fungus will occur, notably, in immunocompromised people.C. Albicans includes a parasexual cycle that seems to be stimulated by environmental stress.

Aspergillus

The most common pathogenic species are Aspergillus fumigatus and genus Aspergillus flavus. genus Aspergillus flavus produces aflatoxin that is each a poison and a carcinogen and which may doubtless contaminate foods like nuts. aspergillus fumigatus and aspergillus clavatus will cause allergic illness. Some aspergillus species cause illness on grain crops, particularly maize, and synthesize mycotoxins together with aflatoxin. Aspergillosis is that the cluster of diseases caused by aspergillus. The symptoms include fever, cough, chest pain, or breathlessness. Usually, solely patients with weakened immune systems or with different respiratory organ conditions are vulnerable.

The spores of aspergillus fumigatus are ubiquitous within the atmosphere. A. fumigatus is an opportunistic infective agent. It will cause doubtless fatal invasive infection in immunocompromised people.A. fumigatus includes a totally purposeful sexual cycle that produces cleistothecia and ascospores.

Cryptococcus.
Cryptococcus neoformans will cause a severe type of meningitis and meningoencephalitis in patients with HIV infection and AIDS. the bulk of Cryptococcus species live in the soil and don't cause illness in humans. Cryptococcus neoformans is the major human and animal pathogen. Cryptococcus laurentii and Cryptococcus albidus are best-known to often cause moderate-to-severe illness in human patients with compromised immunity. Cryptococcus gattii is endemic to tropical elements of the continent of Africa and Australia and may cause illness in non-immunocompromised individuals.

e) Importance of Fungi in Human Life

Although we often think about fungi as organisms that cause illness and decay food, fungi are vital to human life on several levels. They influence the well-being of human populations on an outsized scale as a result of they're a part of the nutrient cycle in ecosystems. They even have different ecosystem uses, like pesticides.

Biological insecticides

As animal pathogens, fungi facilitate to regulate the population of damaging pests. These fungi are terribly specific to the insects they attack; they are doing not infect animals or plants. Fungi ar presently underneath investigation as potential microbic insecticides, with several already on the market. as an example, the fungus Beauveria bassiana may be a pesticide being tested as a possible biological control agent for the recent spread of emerald ash borer.

Farming

The mycorrhizal relationship between fungi and plant roots is crucial for the productivity of farm land. while not the fungous partner in root systems, 80–90 % of trees and grasses wouldn't survive. Mycorrhizal fungous inoculants are available as soil additives from horticulture provide stores and are promoted by supporters of organic agriculture.

Food

Fungi figure conspicuously within the human diet. Morels, shiitake mushrooms, chanterelles, and truffles are thought of delicacies. The meadow mushroom, agaricus campestris, seems in several dishes. Molds of the genus penicillium ripen several cheeses. They originate within the natural surroundings like the caves of roquefort, France, wherever wheels of sheep milk cheese ar stacked to capture the molds answerable for the blue veins and pungent taste of the cheese.

Medicine

Many secondary metabolites of fungi are of nice business importance. Fungi naturally manufacture antibiotics to kill or inhibit the growth of microorganism, limiting their competition within the natural surroundings. vital antibiotics, like penicillin and also the cephalosporins, will be isolated from fungi.