Medical Botany: Systematics of Fungi

• Courses in Medical Botany (2024) covers mycology
• Choukry KAZI TANI presents the systematics of fungi

Systematics of Fungi

• Chytridiomycetes, Zygomycetes, Ascomycetes, Basidiomycetes, Glomeromycetes and Imperfect fungi are all fungi

Ascomycetes

• 64,000 ascomycete species represent 65% of fungal diversity
• Nearly 60,000 ascomycete species are in lichens
• Most ascomycetes live on land and have perforated septa
• Septa aren't associated with nuclear division
• Central pores, 300-500 nm wide, allow cytosol, mitochondria and nuclei to pass
• Glucan plugs progressively block the pores, isolating older portions of the mycelium

Vegetative Apparatus

• Each individual article usually has multiple nuclei
• Incomplete septa increase hyphal rigidity, avoid substance loss if there is injury
• Ascomycetes include cup fungi, yeasts, and blue, green, pink, and brown molds
• Oidium diseases in plants are caused by ascomycetes

Sexual Reproduction

• Asexual reproduction is more common.
• Spermatia from the male gametocyst are captured by the trichogyne of the female gametocyst in some primitive species
• In most Ascomycetes, the trichogyne fuses and male nuclei pass into the female gametocyst

Sexual Reproduction Simplification

• Spermatocyst may no longer attach to the trichogyne and only dicaryons form through autogamy or parthenogenesis
• The spermatocyst only plays a hormonal or trophic role
• Over the course of evolution in truffles and morels, sexual reproduction may be limited to the encounter of two haploid filaments from different spores
• The fusion creates a dicaryotic filament
• There is no longer any sexual organ formation

Pyronema omphalodes Sexual Reproduction

• Sexual spore formation in Pyronema omphalodes happens in asci
• Plasmogamy fuses the antheridium and ascogone
• There are male and female nuclei
• A multinucleated dicaryotic zygote called a cenozygote increases in volume during maturation

Cenozygote Germination

• Cenozygotes form filaments inside which dicaryons migrate
• Simultaneously, haploid mycelial hyphae from the ascogone multiply and form nutritive paraphyses, and a protective ascotheca
• Inside the ascotheca, the filaments lengthen. Dicaryon nuclei divide by mitosis conjunctives to give rise to dicaryotic hyphae

Dangeard Hyphae

• For each article have only two nuclei of a dicaryon, a complex elongation is done by dangeardiennes hyphae
• Dangeard Hyphae are named differently: Anastomosis loop, conjugation loop and Dangeard loop
• These loops ensure dicaryotization

Continued Pyronema Reproduction

• The terminal cell of the hypha with two nuclei extends and forms a lateral, backward-hooking outgrowth
• Nuclei A and B divide to make nuclei A1, A2, B1 and B2
• Two nuclei go to the hypha's end (A1 and B1)
• The loop end merges with the hypha upstream, and a nucleus transfers to a section above its origin
• Meanwhile, a septum separates the tube and loop into two

Ascus Development

• Some dangeardian hyphae become ascogenous, in which two dicaryotic nuclei fuse
• The diploid cell elongates to form an ascus, and then reduction division occurs and generates four then eight haploid nuclei.
• Each is surrounded by cytoplasm, a wall, and becomes a spore. At the top of the ascus is a valve or operculum.
• A pressure increase in the cytosol propels ascospores outward, sometimes several centimeters

Pyronema Sporophore at Maturity

• The sporophore is formed of an external envelope, a layer of haploid mycelium at the origin and a open cup
• Inside are the ascogenous hyphae surmounted by asci and thin, elongated red filaments referred tp as paraphyses.
• The ascus and paraphysis collection is the hymenium

Hymenium with Ascocarp

• Hymenium is limited by the ascocarp
• The ascocarp can form within cavities in an interwoven hyphal mass (pseudothecia) or be contained in closed organs that tear open when mature (cleistothecia)
• It can be open with an opening called an ostiole (perithecia), or can be cup-shaped (apothecia or peziza) or be spherical (truffle).

Morphology

• Truffle shapes have appeared multiple times during evolution in Basidiomycetes and Ascomycetes
• Mycologists suggest that, with climate drying, sporophores matured poorly because spores remained in tissues, preventing wind dispersion
• Organisms that consume sporophores and defecate the spores are beneficial
• Scented mushrooms (thioether) attract animals, increasing consumption chances

Truffles and Spores

• Spores most be made before truffles can be eaten
• Wet climates may cause them to rot early, causing selection to favor below-ground protection
• Olfaction is key when animals detect the fungi
• Some specimens are designated Secotium, where it appears they are sick

Asexual Reproduction

• Asexual multiplication is predominant in the Ascomycotina
• This is achieved by uninucleate spores or conidia from budding specialized sporocysts
• Phialides are commonly grouped at the ends of stalks to ease conidia dispersion
• To facilitate dissemination, specialized sporocysts are typically groups at the end of stalks called conidiophores
• By regression, cells of the thallus bud (blastospores)

Spores

• Specialized sporocysts can only form limited spores, the phialide can a number of spores which facilitates species dissemination
• Phialides and condiophores can be combined in many ways
• In mucedinous forms, corresponding to the ordinary molds, they are placed directly on the mycelium forming a coating
• In acervular or sporodochial forms, it is laid on hyphae mycelia forming a thick aggregate
• The fruit bodies are enclosed in thick envelopes of hyphae in the form of a cup

Taphrinomycetes Class

• Ascomycota are identified by the characteristics of ascocarps, asci and ascospores
• Taphrinomycetes have bare asci arranged in a layer on the surface of parasitized organs
• Cylindrical asci with truncated ends have eight ascospores that can multiply by budding
• This class has one family, Taphrina. These are internal parasites of aerial parts and fruits

Saccharomycetes Class

• Saccharomycetes class is limited to Saccharomycetaceae
• The yeasts have elements multiplying asexually by budding
• The mycelial stage is reduced
• Blastospores can be related to their stage of growth.
• Nutrients in the environment stop budding and contain four ascospores
• Sizes of ascospores are often used for species identification
• Saccharomycetaceae are homothallic and anascosporées species lack sexual reproduction

Discomycetes Class

• Discomycetes groups the Euascomycetes has a apothécies
• This includes the pézizzales family with with shapes like cups, gyromitres and hare ears
• The group features tubercles with saprophytes that have undergone changes in sporophores and has the disappearence of sexuelle division
• The class also includes lėcanorales which include the majority of ichėnisėes

Discomycetes types of apothecia

• The pyrenomacées and pézizacėes apothecia in the shape of cups
• The helvellacės has an hyménium over a thin variable shape of form
• The morchellacės has a stroma and upper part with many cavities called as apotheciės

More about the Classes

• Helvellas and some pezizaceae are edible, but must be cooked or dried
• Raw can cause mortal toxicities
• Gyromitrin is a toxin that can be fatal. The limit of the toxin fluctuates between individuals
• People can consume the pezize without becoming sick but then are over the criticism and die after re-consuming

Gyromitrin

• Gyromitrin is a poison and affects the nervous system
• Long incubation syndromes will show symptoms and cramps and abdominal
• Lack of Fever or movement will be followed by convulsion and comma
• Antidotes are available to combat
• Conduct during is include cleaning and administrating some treatments to help

Tubérales (truffles)

• This order can be saprophytes or symbioses
• There is a absence of sexuelle duplication which occurs direct
• These truffles have two filaments wich cause a cell from the dycarians

Truffles, continued

• Truffles are subterranean fungi, some species are edible and cultivated
• Black truffles are black in the surface and different textures
• The textures come with interactions of species such as oaks
• Yellos truffles are smooth or granulated
• The truffe has veins and mycorrhizal relations with different species

Truffle anatomy

• At maturity truffle reveals the presence of marbling and a network
• Mycelia anastomoses allows the exchange of water and gas
• It shows that the surface of the areas is fertile
• The production of the genes produce meoise or ascospores
• mycelium form the tree

Truffle cycle

• Truffle is an association symbiotique, in the region of the tree
• Powerfull fragrance attract animals

Value of nutrition in truffles

• They contain a lot of quantity and contains glucides and can have an amout of B2 B3 B5

Sordariomycètes Classification

• That classes are ascomycontas with asques regrouped
• Aspects can be diverses
• The multipliers interviens by sexuée
• Species duplicates due to their voie asexuée

Claviceps purpurea

• The order had a series of parasytes attacks

Infestion by Ergot

• Produces 2 filament types in the ovary which attract insectes
• It condensates masses wich will fall
• Ater the season will produce a mass from inside

Actions of Scleroite with Indolie

• agents that produces contamination
• A species of developpent des sclèrotes colerated developpent with cordécépine.

Eurotiales Class

• Have characteresitics for sporphores
• asques and spore shape

Gymnomascées family

• Has propriotiés of the tissus and cheveux and onglès .
• Contains more than 30 species , parasties

Aspergilléses family

• that include moisture is verry communes
• and only reproducte par voies excepetionnelles
• More than 300 species identified
• and causes affections
• the penucilline is synthesed by de grisofulvino