Fungi and ecosystem mode of nutrition

Fungi and ecosystem mode of nutrition
1st sem MSc

1. FUNGI AND ECOSYSTEM

2. INTRODUCTION Many fungi are saprobes obtain nutrition from decaying organic matter. All fungi are heterotrophs. They are multicellular. From crop and food spoilage to severe infections in animal species, fungal parasites and pathogens are wide spread and difficult to treat. KKR1116 2

3. Fungi can be studied these groups : Saprophytic fungi : feeds on dead and decay organic matter. Parasitic fungi : obtains nutrition by living on other living organisms . Keratinophilic fungi :Natural coloni sers of keratinic substrates. Coprophilic fungi :saprobic fungi that grow on animal dung. KKR1116 3

4. SAPROPHYTIC FUNGI These are fungi that cannot make their own food as they are called heterotrophs. In order to survive they feed on dead and decaying matter. And keep ecosystems stocked with the inorganic nutrients necessary for the plant growth. Found particularly true in tropical regions, where temperature and humidity are often very high. Example :mushrooms and molds Rhizopus, mucor, yeast, etc. KKR1116 4

5. Mushrooms on dead tree KKR1116 5

6. Parasitic fungi They are pathogenic fungi which obtain their nutrition by living on other living organisms such as plants and animals as their hosts. Plant parasitic fungi obtain nutrients from a living plant host, and causes diseases characterized by symptoms. Biotrophic fungal pathogens obtain nutrients from living host tissues, often via specialized cells called haustoria that forms inside host cells. Many plant pathogens are fungi that cause tissue decay and eventual death of the host. Some fungal pathogens spoil crops by producing potent toxins. OBLIGATE PARASITE : eg . rust of wheat - Puccinia triticina , downy mildews of grapes – Plasmopara viticola . FACULTATIVE PARASITE : eg. Armillaria Fungi are also responsible for food spoilage and rotting of stored crops. Example : in plants : downy mildews of grapes, & rust of wheat. in animals : in humans aspergillosis, histoplasmosis, ringworm, candidiasis etc. KKR1116 6

7. PARASITIC FUNGI in plants Downy mildews of grapes: It is a very extremely serious fungal desease of grapes that results in severe crop loss. It is caused by fungus Plasmopara viticola . Pathogen attacks all green parts of the vine, especially leaves. Lesions on leaves are angular, yellowish, sometimes oily located between the veines As a disease progress white cottoni growth an be observed Severely infescted leaves will drop If enough defolication occurs, the overwintering buds will be more susceptaible to winter injury Infected shoot tips become thick, curl, and eventually turn brown and die. KKR1116 7

8. DOWNY MILDE OF GRAPES KKR1116 8

9. PARASITIC FUNGI in animals Fungi affect animals, including human, in several ways. A mycosis is a fungal disease that results from infection and direct damage. They colonize & destroy tissues. Mycotoxicosis is poisoning of humans (other animals) by fungal toxins (mycotoxins). Many fungal infections are superficial i.e they occur on the animal’s skin (mycoses). EXAMPLE : Aspergillus causes allergic reactions & mild pneumonia in susceptible individuals. - yeast Candida albicans inhabitants of mouth, throat, colon & reproductive organs called candidiasis KKR1116 9

10. KERATINOPHILIC FUNGI Fungi that cause the superficial mycoses of the epidermis, hair and nails rarely spread to the under lying tissues. This fungi are often misnamed “dermatophyte”, from the Greek word dermis meaning skin and phyte meaning plant, all they are not plants. Dermatophyte are also called “ring worms” because of the red ring they cause on the skin. They secrete extracellular enzymes that break down keratin [ a protein found in hair, skin and nails],causing condition such as athlete’s foot and jock itch. This condition are usually treated with over-the-counter tropical creams and powders, they are easily cleared. More persistent superficial may require prescription oral medications. Ingestion of toxins from poisonous mushrooms are referred as Mycetismus . Example : Microsporum , Epidermophyton , Trichophyton KKR1116 10

11. TRYCHOPHYTON Trichophyton spp. are keratinophylic fungi responsible for the majority of skin infections in humans. They can be transmitted in many different ways, including person-to-person contact, and also contact with geophilic organisms in the soil, Which spread via animal vector, and indirectly through inanimate objects carrying the fungi. Infections are primarily localized to hair, nails, and outer layers of skin, reflecting the affinity of fungi for keratin and the inability of fungi to invade deeper tissues or organs in immunocompetent skin. Infections can cause a no. of symptoms, including exclusive inflammation, itching, and discolored, scaly skin lesions. These infections, referred to as dermatophytosis or tinea infections, are named for the body sites involved. KKR1116 11

12. TRYCHOPHYTON SPECIES Tinea capitis -Scalp and hair Tinea corporis -Ringworm Can occur anywhere on skin; commonly on limbs Tinea barbae -Skin/hair of beard/ mustache area Tinea faciei - Face, non-bearded area Tinea manuum - Hands Tinea cruris- Jock itch Groin Tinea pedis -Athlete's foot Feet Tinea unguium - Onychomycosis Fingernails and toenails. KKR1116 12

13. TINEA CORPORIS TINEA CAPITIS TINEA UNGUIUM KKR1116 13

14. COPROPHILIC FUNGI Coprophilic fungi (dung loving fungi) are type of saprobic fungi that grow on animal dung. The hardy spores of coprophilic species are unwittingly consumed by herbivores from vegetation, and are excreted along with the plant matter. The fungi then flourished in feces, before releasing their spores to the surrounding areas. Examples : Pilobolus , & Chaetomium Spp. KKR1116 14

15. PILOBOLUS Pilobolus also called as hat thrower fungus They are cosmopolitan genus of at least five species in family pilobolaceae (order Mucorales) that are known for explosive spore dispersal. They feed on feces of grazing animals. These fungi are diminutive, usually less than 10mm(0.4inch) in height, and are characterized by a sparse mycelium that produce unbranched sporangiophores(fruiting body) capped with black sporangia(spore clusters). They exhibit squirt-gun mechanism to disperse their sporangia up to 3metres. KKR1116 15

16. CHAETOMIUM Chaetomium is a dematiaceous filamentous fungi. Found in soil, air, & plant debris. Its being a contaminant, Chaetomium spp. Also encountered as causative agent of infections in humans. Some species are thermophilic and neutrophilic in nature. KKR1116 16

17. PILOBOLUS KKR1116 17

18. REFERENCES BOTANY FOR DEGREE STUDENTS BY V R VASHISHTA INTRODUCTION TO MYCOLOGY: BY R S MEHROTRA AND K R ANEJA WEBSITE SOURCE :WWW.BRITANNICA.COM/SCIENCE WWW.NCBI.NLM.NIH.GOV KKR1116 18

19. THANK YOU KKR1116 19