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Discomycetes

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Discomycetes are a large group of ascomycete fungi that produce fruiting bodies called apothecia. They can be saprobes, parasites, or form lichens and mycorrhizal relationships. Discomycetes are classified based on whether their apothecia have an operculum or not. Some economically important discomycetes include edible mushrooms in the order Pezizales and truffles in the order Tuberales. The apothecium contains the hymenium layer where asci and ascospores are produced.

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DISCOMYCETES SRIVANI GAYATHRI
Contents • Introduction • Habitat • Classification • Apothecium Structure • Conclusion • Reference
Introduction A vast group-2,720 genera and 28,650 species. This includes the members with cup-shaped/ saucer-shaped, some are club-shaped, mushroom-like, sponge-like etc.. These produce fructification called Apothecium, is the main feature of identification. Discomycetes are Ascomycetes with apothecium.
Habitat Most of the members are saprobes in nature but few are parasites, cause serious diseases of economic plants. Some are coprophillus and also constitute lichens. For instance., Sclerotinia fruticola- Brown rot in pear Quercus -Mycorrhizae forming
Classification Discomycetes- grossly classified- based on the presence/ absence of Operculum. • Inoperculate • Operculate
Ainsworth divided Discomycetes into 6 orders viz., • Pezizales • Tuberales • Rhytismatales • Ostropales • Helitiales • Cyttariales Each order contains some families and few genus
Pezizales • Largest of operculate Discomycetes usually saprobes on soil, dead wood, plant debris/ humus • Apothecia may be fleshy/ brittle/ leathery / rarely gelatinous • The asci are arranged in a distinct hymenium with paraphyses • Edible- Morchella esculenta
PEZIZA BADIA PEZIZA CEREA
Tuberales • Commonly called Truffles • Used as food, in liquor making, for scenting tobacco, in perfumes etc • The ascomata remains closed and are fleshy to leathery/ globose with a hymenium • Mycorrhizae- Quercus
TUBER RUFUM
Rhytismatales(Phacidiales) • Saprobes/ plant parasites on leaves and wood • Produce characteristic apothecoid ascocarps immersed in a stroma/ host tissue • Asci are inoperculate and apically thick Rhytisma
Ostropales • Saprobes / parasites of herbaceous/ woody stem • Crustose lichen formation • Asci- long and cylindrical • Young ascal apex, thick, traversed by a pore through which ascospores are discharged
Crustose lichen with Apothecia
Helotiales • Inoperculate forms • Saprobes on soil, dead wood, dung and parasites that cause plant diseases (Sclerotinia spp.) • Ascocarps may be superficial or immersed in substratum
Cyttariales • Large ascomata-spherical to pyriform • Asci are operculate • Cushion of epiplasm remains between ascospores CYTTARIA ESPINOSAE
Apothecium • It is divided into 3 anatomical regions - Hymenium - Subhymenium - Excipulum • Hymenium is made of cylindrical/ club-shaped asci and paraphyses in a palisade layer • Subhymenium is a zone of tissue that give give rise to asci and paraphyses • Excipulum- 2 parts- ectal and medullary
Discomycetes
Stages of Ascospore formation
Conclusion The members commonly produce asci within apothecium, may be operculate/ inoperculate. Morchellaceae under Pezizales has the members like mushrooms, which resemble the mushrooms.
Reference • R.S. MEHROTRA & K.R. ANEJA (2010) AN INTRODUCTION TO MYCOLOGY Pg no. 363-389 New Age International (p) Ltd., Publishers • JOHN WEBSTER, 1970, Introduction to fungi, pg no. 246-272. Cambridge university press •http://www.symbiology.com/pdf/Gargas7 .pdf
Discomycetes

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Discomycetes

  • 2. Contents • Introduction • Habitat • Classification • Apothecium Structure • Conclusion • Reference
  • 3. Introduction A vast group-2,720 genera and 28,650 species. This includes the members with cup-shaped/ saucer-shaped, some are club-shaped, mushroom-like, sponge-like etc.. These produce fructification called Apothecium, is the main feature of identification. Discomycetes are Ascomycetes with apothecium.
  • 4. Habitat Most of the members are saprobes in nature but few are parasites, cause serious diseases of economic plants. Some are coprophillus and also constitute lichens. For instance., Sclerotinia fruticola- Brown rot in pear Quercus -Mycorrhizae forming
  • 5. Classification Discomycetes- grossly classified- based on the presence/ absence of Operculum. • Inoperculate • Operculate
  • 6. Ainsworth divided Discomycetes into 6 orders viz., • Pezizales • Tuberales • Rhytismatales • Ostropales • Helitiales • Cyttariales Each order contains some families and few genus
  • 7. Pezizales • Largest of operculate Discomycetes usually saprobes on soil, dead wood, plant debris/ humus • Apothecia may be fleshy/ brittle/ leathery / rarely gelatinous • The asci are arranged in a distinct hymenium with paraphyses • Edible- Morchella esculenta
  • 9. Tuberales • Commonly called Truffles • Used as food, in liquor making, for scenting tobacco, in perfumes etc • The ascomata remains closed and are fleshy to leathery/ globose with a hymenium • Mycorrhizae- Quercus
  • 11. Rhytismatales(Phacidiales) • Saprobes/ plant parasites on leaves and wood • Produce characteristic apothecoid ascocarps immersed in a stroma/ host tissue • Asci are inoperculate and apically thick Rhytisma
  • 12. Ostropales • Saprobes / parasites of herbaceous/ woody stem • Crustose lichen formation • Asci- long and cylindrical • Young ascal apex, thick, traversed by a pore through which ascospores are discharged
  • 13. Crustose lichen with Apothecia
  • 14. Helotiales • Inoperculate forms • Saprobes on soil, dead wood, dung and parasites that cause plant diseases (Sclerotinia spp.) • Ascocarps may be superficial or immersed in substratum
  • 15. Cyttariales • Large ascomata-spherical to pyriform • Asci are operculate • Cushion of epiplasm remains between ascospores CYTTARIA ESPINOSAE
  • 16. Apothecium • It is divided into 3 anatomical regions - Hymenium - Subhymenium - Excipulum • Hymenium is made of cylindrical/ club-shaped asci and paraphyses in a palisade layer • Subhymenium is a zone of tissue that give give rise to asci and paraphyses • Excipulum- 2 parts- ectal and medullary
  • 18. Stages of Ascospore formation
  • 19. Conclusion The members commonly produce asci within apothecium, may be operculate/ inoperculate. Morchellaceae under Pezizales has the members like mushrooms, which resemble the mushrooms.
  • 20. Reference • R.S. MEHROTRA & K.R. ANEJA (2010) AN INTRODUCTION TO MYCOLOGY Pg no. 363-389 New Age International (p) Ltd., Publishers • JOHN WEBSTER, 1970, Introduction to fungi, pg no. 246-272. Cambridge university press •http://www.symbiology.com/pdf/Gargas7 .pdf