Lecture 7 General Characters of fungi - Vegetative structures (1).pptx

Pathology

1. Fungi Vegetative structures Cell structure Fungal Tissue arrangem e nts Specialized somatic structures Resting structures

2. Fungi are the microscopic, filamentous, heterotrophic, eukaryotic , achlorophyllous , unicellular or multicellular organisms which may reproduce by asexual and sexual spores . Fungi is a plant which can not differentiated into leaf, root, Stem etc.

3. Vegetative structure Plant Fungi

4. Cytoplasm contains organelles such as mitochondria, Golgi apparatus, ribosomes, vacuoles, vesicles, microbodies, endoplasmic reticulum, lysosomes

5. True fungi Cell wall made up of Chitin False fungi Cell wall made up of Cellulose chief storage products of fungi are glycogen and lipid Plasma membrane or plasmalemma cell membrane which enclosed the living protoplast of the fungal cells

6. Nucleus has nuclear envelope comprising of two typical unit membranes and a central dense area known as nucleolus , which mainly consist of RNA

7. Thallus (Pl. Thalli) – The entire fungal body

8. Thallus Eucarpic thallus Holocarpic thallus Mushroom yeast Synchytrium endobioticum

9. Only portion of thallus become reproductive and the remaining continue to grow vegetatively vegetative and reproductive phases occur together thallus is differentiated into vegetative part and reproductive part Oomycota, Ascomycota, Basidiomycota Eucarpic thallus / Filamentous thallus

10. Entire thallus is converted into reproductive structure vegetative and reproductive phases don’t occur together in the same thallus The thallus does not show any differentiation on vegetative and reproductive structure e.g. yeast, Synchytrium endobioticum Holocarpic thallus / Unicellular thallus Y east

11. Hypha (Pl. Hyphae) - Unit of Fungi Mycelium (pl. Mycelia) - The hyphal mass

12. Tubular, transparent filament , usually branched, composed of an outer cell wall and a cavity (lumen) lined or filled with protoplasm including cytoplasm Hyphae are divided into compartments or cells by cross walls called septa septate (with cross wall) coenocytic (aseptate - without cross wall) Hyp h a

13. septate (with cross wall) Coenocytic - aseptate (without cross wall)

14. Simple septum Dolipore septum

15. hyphal mass or network of hyphae constituting the body (thallus) of the fungus is called as mycelium Mycelium Based on their growth on the host Ectophytic e.g., Erysiphe sp. Endophytic e.g., Leveillula taurica Septate Ase p ta t e Intercellular I n t r acellu l ar Coloured Hyaline ( Co l ourl e s s )

16. Intercellular mycelium penetrates in between cells Intracellular mycelium penetrates within the cell

17. Hyaline Coloured Aseptate Pythium sp. Phytophthora sp. Septate Fusarium sp Pyricularia Aseptate Rhizopus sp. Mucor Septate Alternaria , Helminthosporium sp. M y c e li u m

18. Types of mycelium based on presence of Nucleus Monokaryotic Homo k ary o tic Dikaryotic Heterokaryotic

19. Monokaryotic mycelium (uninucleate) Mycelium contains single nucleus that usually forms part of haplophase in the life cycle of fungi. Dikaryotic mycelium (binucleate) Mycelium contains pair of nuclei (dikaryon), which denotes the diplophase in the life cycle of fungi. Homokaryotic mycelium The mycelium contains genetically identical nuclei . Heterokaryotic mycelium The mycelium contains nuclei of different genetic constituents . Multinucleate The fungal cell contains more than 2 nuclei .

20. 1. Prosenchyma loosely woven and the hyphae lie parallel to one another Plectenchyma loosely or compactly woven fungal tissues have di s tin g uisha b le and typical elongated cells 2. Pseudoparenchyma (Gr. Pseudo = false) consists of closely packed, more or less isodiametric or oval cells resembling the parenchyma cells of vascular plants not di s tin g uisha b le

21. Fun g i Th a ll u s Mycelium Hypha Eucarpic Holocarpic Septate & Aseptate Coloured & Hyaline Plectenchyma Prosenchyma Pseud o p a ranch y ma Short s u mmary

22. Specialized somatic structures Rhizoid Appressorium Hau s t ori u m St r oma

23. 1. Rhizoid (Gr. rhiza = root + oeides = like) a short, root-like filamentous outgrowth of the thallus generally formed in tufts at the base of small unicellular thalli or small sporophores Anchoring or attachment organ Absorption of nutrients C h y t ridi o my c e t es, Oomycetes Zygomycetes Specialized somatic structures

24. 2. Appressorium (Anchoring organ) (pl. appresoria; L. apprimere = to press against) Uredinales (rust fungi), Erysiphales (powdery mildew fungi) other fungi in their parasitic or saprophytic stages Pressing organ Attach to the surface of the host

25. 3. Haustorium (Feeding or absorbing organ) (sing. haustorium; L. haustor = drinker) knob-like branched like a miniature root system balloon like special hyphal structures or outgrowths of somatic hyphae sent into the cell to absorb nutrients

26. 4. Stroma (pl. stromata) (Gr. stroma = mattress) a compact, somatic structure or hyphal aggregation similar to a mattress or a cushion made up of prosenchyma and pseudoparenchyma Stromata bear sporophores producing spores Pho r e Stem sporophores sp o r es

27. Resting structures / Resting bodies / Specialized structures / overwintering or oversummering structures / Dormant structures Rhizomorph Sclerotium Chl a my dosp o r e

28. Long root like strands of closely packed parallel or interwoven hyphae forming compact masses in order to withstand adverse condition 1. Rhizomorph (Gr. rhiza =root + morphe = shape) Found in honey fungus or honey agaric Armillariella mellea Grow faster than the mycelial strands

29. 2. Sclerotium 1.Hard structures resistant to unfavourable physical and chemical conditions 2. Germinate on the return of favourable conditions thick-walled resting structures, which contain food reserves Rhizoctonia, Sclerotium, Sclerotinia, Claviceps, Botrytis a resting body formed by aggregation of somatic hyphae into dense, rounded, flattened, elongated or horn-shaped dark masses

30. Types of Sclerotia Sclero t ium r o lf s i i , S. cepivorum and Rhizoctonia solani Myceliogenous Germinate and directly produce the mycelium Sporogenous bear mass of spores. e.g. Botrytis cinerea 3. Carpogenous Produce a spore fruit e.g. Sclerotinia sp. Claviceps purpurea

31. Intercalary chl a my d o s p o r es Apical chl a my d o s p o r es 3. Chlamydospore is a thick-walled thallic conidium that generally function as a resting spore e.g. Fu sa r i um Mucor Conidium Asexual spore of fungi They become separated from each other by the disintegration of intervening hyphae

32. Inoculum – Any part of the pathogen that is capable of establishing infection Inoculum Vegetative mycelium S p o r es Specialized mycelial structures e.g. Rhizomorph, Sclerotia and Chlamydospores Asexual spores Sp o rang i os p o r es Zoo s p o r es Conidia Dormant mycelium Sexual spores Oospores, Zygospores, Ascospores, Basi d i o s p o r es

33. Haustorium Rhizoids S p o r e Spore germination and Absorption of Nutrients Germ tube

34. Reproduction Sexual fruiting bodies and Sexual spores Asexual fruiting bodies and Asexual spores Thank you

35. Fill in the blanks: Mass of Hyphal mass is Mycelium Hypha is a unit of Fungi Appressorium is a Anchoring organ of Fungi Drinking organ of fungi is Haustorium Thick walled conidium is Chlamydospores Loosely or compactly woven fungal tissues are called as Plectenchyma Thallus is Entire body of Fungi Hyaline means Colourless Aseptate hypa also called as Coenocytic Cell wall of True fungi made up of Chitin