Budding :
Bud formation in yeasts
In its simplest form asexual reproduction is by budding or binary fission. The onset of the cellular events is accompanied by the nuclear events of mitosis.
The initial events of budding can be seen as the development of a ring of chitin around the point where the bud is about to appear. This reinforces and stabilizes the cell wall. Enzymatic activity and turgor pressure the act to weaken and extrude the cell wall. New cell wall material is incorporated during this phase. Cell contents are then forced into the progeny cell.
Yeasts budding:



Chytridiomycete asexual reproduction :
Chytrids are quite distinct from other fungi as they have extremely simple thalli and motile zoospores. Species within this group are very simple in structure and may only consist of a single cell, perhaps with rhizoids to anchor it on to a substrate.



Holocarpic chytrid
This is a diagram of a holocarpic chytrid, one where the entire thallus consists of only one cell with rhizoids. These are usually parasitic on aquatic plants or fish. The fungus 'feeds' from its substrate via its rhizoids. The entire cell contents will convert to motile zoospores.

Zygomycete Asexual Reproduction
An example of a zygomycete is black bread mold (Rhizopus stolonifera), a member of the Mucorales. It spreads over the surface of bread and other food sources, sending hyphae inward to absorb nutrients. In its asexual phase it develops bulbous black sporangia at the tips of upright hyphae, each containing hundreds of haploid spores. If the mycelia of complementary mating types are present, the fungus reproduces sexually and produces zygosporangia. Zygosporangia are typically thick-walled, highly resilient to environmental hardships, and are metabolically inert. When conditions improve, however, they germinate to produce a sporangium or vegetative hyphae.

PROCESS OF SPORULATION


Asexual reproduction in Ascomycetes and deuteromycetes
The process of spore formation in most members of the higher fungal groups is again based largely on the formation of aerial mycelium and the differentiation of the hyphal tip. However, unlike the process seen in the Zygomycetes, the process here involves something much more like the budding we see in the yeasts. This is termed a blastic process, which involves the blowing out or blebbing of the hyphal tip wall. The blastic process can involve all wall layers, or there can be a new cell wall synthesized which is extruded from within the old wall.The hypha that creates the sporing (conidiating) tip can be very similar to the normal hyphal tip, or it can be differentiated. The most common differentiation is the formation of a bottle shaped cell called a phialide, from which the spores are produced.



Sexual reproduction :
It undergoes a process called meiosis
Sexual reproduction introduces the possibility of variation into a population, and this is why most fungi have a sexual phase. To achieve sexual reproduction it is necessary to have two mating type haploid nuclei (n + n), or a diploid (2n) nucleus. In the case of the two haploid nuclei they must fuse to form a diploid first, but once fused the nuclei undergo meiosis, which is the reduction division that potentially brings about variation in the progeny. These event are followed by the formation of spores, which in most cases are resting spores that can withstand adverse conditions.
It is the fusion of two nuclei occurs – zygote with a diploid nuclei forms
Process is called karyogamy
The zygote undergoes meiosis – 4 hyploid spores (n)
Spores are released – form new mycelia



Sexual reproduction in Zygomycetes:
There are two possible nuclear states in the mycelia of this group of fungi. They can have a single type of nucleus in their mycelium, a condition termed termed homothallism, or they can contain the two mating type nuclei within their mycelium, termed heterothallism. If the fungus is homothallic the first event in the onset of sexual reproduction has to be somatic fusion. This is termed conjugation. To achieve such a mating it is necessary to attract each other and an elaborate sequence of cellular and biochemical events have been established for some of these fungi. This signalling involves the secretion of inducer molecules that are responsible for causing the formation of zygophores, modified hyphal tips, and these then grow towards each other long a gradient of hormone.



Sexual reproduction in the Ascomycetes:
In this group of fungi there are no specialized organs of hyphal fusion, different mating type mycelia merely fuse with each other to form transient dikaryons, mycelia with two mating type nuclei within it. The dikaryotic mycelium can differentiate to from varying amounts of sterile mycelium around what is to become the fertile tissue of the fruit body. In yeasts, a single, diploid yeast will undergo meiosis, producing four haploid progeny cells, but in more complex fungi there are a sequence of cellular and nucleic events that ensure an organized fertile layer.



Sexual reproduction in the Basidiomycetes:
Onset of sexual spore formation is triggered by environmental conditions and in the larger Basidiomycetes begins with the formation of a fruit body primordium. The primordium expands and differentiates to form the large fruit bodies of mushrooms and toadstools. The mycelium within this structure remains as a dikaryon, diploid formation only occurring within the modified hyphal tip called the basidium. Meiosis occurs within the basidium, and the four products are extruded from the tip of the basidium on sterigma. Usually this event occurs across a large area of basidia called a hymenium, or fertile layer. It is usually formed over an extensive sterile layer of tissue like a mushroom gill.
Basidiomycetes are characterised by the most complex and large structures found in the fungi. They are very rarely produce asexual spores. Much of their life cycle is spent as vegetative mycelium, exploiting complex substrates.
A preliminary requisite for the onset of sexual reproduction is the acquisition of two mating types of nuclei by the fusion of compatible mycelium. This creates a dikaryon where single copies of the two mating type nuclei are held within every hyphal compartment for extended periods of time. Maintenance of the dikaryon requires elaborate septum formation.
Three major divisions in the basidiomycetes.
1. Hymenomycetes.
Basidia are in extensive fertile layer which are susceptible to rain when exposed. Spores are actively discharged from a protected hymenium when ripe. This group includes mushrooms and toadstools, boletes, brackets and coral fungi.
2. Gasteromycetes.
Hymenia line closed cavities in an initially closed fruit body. Basidiospores are released passively by autolysis of the hymenium, and basidiocarps disintegrate at maturity. This group includes earth balls, puff-balls, stinkhorns and birds nest fungi.
3. Teliomycetes.
These are the rusts and smuts, neither of which form large, conspicuous, fruit bodies but invade plants and produce characteristic sporulating lesions in plant tissue.



Dormancy:
Dormancy occurs when spores do not immediately germinate after formation. Dormancy is a break in the life cycle. There are two types, endogenous (constitutive) and exogenous (induced). Endogenous dormancy is due to some internal quality of the spore, a barrier to water or nutrient entry, a metabolic block, or an inhibitor. Self inhibition prevents spores from germinating in dense suspensions. It can be by excessive sensitivity to oxygen or carbon dioxide levels, nutrient competition, or most usually due to the presence of inhibitors.
There can also be physical barriers to germination. In one of the athlete foot fungi, Microsporium gypseum, there is a protein layer around the spore which prevents the uptake of water. This layer is removed by the action of a fungal acid phosphatase enzyme. This enzyme is inhibited by high levels of phosphate, and until phosphate levels in the environment drop the fungus spore does not germinate.
Endogenous (induced) dormancy occurs because of some external condition, and whilst these conditions prevail the spore will not germinate. As soon as the limiting factor is removed the spore germinates.
Optimal environmental signals trigger the end of dormancy and the onset of germination. Chemical stimuli can trigger germination. This is frequently seen in pathogens where host compounds can act as germination stimulants.Germination begins with imbibition, the uptake of water, which can cause a 3 to 20 fold increase in size. Spherical growth also accounts for some of the swelling. Eventually polarized growth starts, with the emergence of a germ tube from the spore. The spore wall may be ruptured and a new cell wall covered germ tube emerges, or the spore wall may be softened and the germ tube then emerges.


Air spora:
In between formation of spores and their eventual germination is a phase where spores are disseminated from their point of origin. Many fungi have elaborate mechanisms for getting their spores into the atmosphere which the best medium through which to spread spores. Many spores are very dry and friable, which means they are light enough to be lifted by air currents into the turbulent air above the boundary layer.
In the countryside this is very typically full of spores from pathogens of agricultural crops, from saprophytes of plant structures and from decaying matter. Species like Penicillium and Cladosporium tend to predominate. In the towns there are fewer agricultural pathogens but there are still hundreds of spores per cubic litre of air. Within homes and workplaces spore numbers can be even higher, and the species distribution tends to differ. In warm, dry areas Aspergillus spp. can become significant members of the air spora.




References:
http://www.newton.dep.anl.gov/newton/askasci/1993/biology/bio015.htm
http://en.wikipedia.org/wiki/Budding
http://www.uccs.edu/~rmelamed/MicroFall2002/Chapter%206/Sporulation.jpg
http://www.plantpath.wisc.edu/pp300-UW/images/image001.jpg
http://www.eol.org/taxa/16104099
http://www.mycolog.com/CHAP4a.htm

Phyla represent the largest generally accepted groupings of animals and other living things with certain evolutionary traits, although the phyla themselves may sometimes be grouped into superphyla. Informally, phyla can be thought of as grouping animals based on general body plan this is morphological grouping. Thus despite the seemingly different external appearances of organisms, they are classified into phyla based on their internal organizations.



Oomycota
Oomycota is a phylum of filamentous protists containing over 500 species. The majority of these organisms are in the groups commonly known as water molds or downy mildew. "Oomycota" means "egg fungi", referring to the oversize oogonia which house the female gametes (eggs). Despite the name and their superficial appearance, oomycetes are not fungi.

Oomycete cells differ from those of true fungi in that they have walls of cellulose and the amino acid hydroxyproline. They are heterotophic, either saphropytic or parasitic. Oomycetes can reproduce asexually, by forming a structure called a sporangium or zoosporangium. Inside these sporangia, zoospores are produced, first the primary zoospore and then the secondary zoospore, which is laterally flagellated. Their flagellum allow the zoospores to move rapidly through water. This type of germination is most common among aquatic and soil-dwelling species. Oomycetes may also germinate directly on the host plant by way of a germ tube. Organisms of Oomycota may also reproduce sexually, by direct injection of the male nuclei (sperm) into the oogonium. This type of reproduction is known as "gametangical copulation".


Chytridiomycota
Chytridiomycota have unicellular or mycelial thalli. Cell walls are made of chitin, although one group has walls made of cellulose. Cell growth can be unicellular, or it can occur in the multicellular mycelium of aseptate hyphae. The thallus is typcially unicellular; it may also have limited hyphal growth. It is not considered mycelial. Hyphal cells are coenocytic, although this is not the case where there are reproductive structures. The ultrastructure of the zoospore is a definitve characteristic of Chytridiomycota. In the structure, ribosomes are aggregated around a nucule that is not enclosed in a nuclear cap. A nuclear cap is an extension of the nuclear membrane. Chytridiomycota have one or two flagella.
Chytridiomycota feed on both living and decaying organisms. They are heterotrophic.


Zygomycota

Zygomycota are terrestrial organisms. They live close to plants, usually in soil and on decaying plant matter. Because they decompose soil, plant matter, and dung, they have a major role in the carbon cycle. Zygomycota are also pathogens for animals, amebas, plants, and other fungi. They form mutualistic symbiotic relationships with plants. In addition, they form commensalistic relationships with arthropods, inhabiting the gut of the organism and feeding on unused nutrients. However, Zygomycota can also be found in acquatic ecosystems. Contain asexual spores called sporangiospores and they are born internally in a sporangium. The sexual spores are thick walled resting spores called zygospores.


Ascomycota
The bodies of Ascomycota are eukaryotic cells surrounded by a wall consisting of chitin and beta glucans. They can be single-celled (yeasts) or filamentous (hyphal) organisms. In addition, they can also be dimorphic. The yeasts grow by budding or fission, while hyphae branch out. Most are haploid, but some can be diploid. Spores are stored in cases (asci), which release clouds of spore smoke. Nucelar fusion and meisos take place within the ascus.
Ascomycota are heterotrophic, obtaining nutrients from both dead or living organisms. In addition, these fungi are capable of consuming almost any liquid, as long as there is water present in it. Sexual reproduction takes place within ascospores or meiospores, and asexually with condia or meitospores. Reproduction takes place in the ascus, with one round of mitosis following meiosis. Some example of ascomycota is saprophytes, insect fungi ( Cordyceps sp), plant parasites (claviceps purpurea, ergot) and industrial fungi (yeast).


Basidiomycota
Basidiomycota has a hypha with complex dolipore septa. it is best known for fruitbodies such as mushrooms, puffballs, and brakcets, it also contains microscopic fungi. Like ascomycota, Bastidiomycota is also home to some forms of yeast. Therefore, the organisms within this classification can be either unicellular or multicellular. There are three major groups within this classification. The first is Urediniomycetes, which includes rusts and other taxa. Second is Ustilaginomycetes, which are largely composed of smuts. Last is the Hymenomycetes, which are comprised of mushrooms and jelly fungi.



http://en.wikipedia.org/wiki/Phylum#List_of_animal_phyla
http://microbewiki.kenyon.edu/index.php/Oomycota
http://microbewiki.kenyon.edu/index.php/Chytridiomycota
http://microbewiki.kenyon.edu/index.php/Zygomycota
http://microbewiki.kenyon.edu/index.php/Basidiomycota

Food:
Mushroom-Button mushroom, Shii-take mushroom



Soya sauce - Aspergillus oryzae, Pediococcus soyae, Saccharomyces rouxii, Torulopsis.



Yeasts - Saccharomyces cerevisae, produce alcoholic beverages e.g. wine and vodka



Cheese - e.g. surface-ripened cheeses and blue-vein cheeses.



Truffles - fleshy fungi with a characteristic taste and aroma.



Tempeh - made with the black bread mould Rhizopus Oligosporus.




Medicine:

Antibiotics - e.g. Penicillin, Griseofulvin, Cephalosporin.


Immunosuppressant - Cyclosporins


Ergot alkaloids - Ergometrine



Industries:
Enzymes - Lipases in detergent industry, glucose oxidase

Organic acids - e.g. citric acid in Coke is produced by an Aspergillus


Biopesticides:
1)Fungi are mixed with polluted water or soil, where they decompose the organic material in pollutants and detoxify them.
2)Fungi also have been used effectively to control insects, fungus pathogens, roundworms, and other organisms that cause harm and disease to agricultural crops.

Research Tools:
1)Fungi are important research tools in the study of biological processes due to how rapidly they grow.
2)Saccharomyces cerevisae was the first eukaryotic organism to be sequenced.