1. IB 371 - GENERAL MYCOLOGY LECTURE 25 THURSDAY, NOVEMBER 20, 2003
LOCULOASCOMYCETES
IB GENERAL MYCOLOGY
LECTURE 25
THURSDAY, NOVEMBER 20, 2003

4. LOCULOASCOMYCETES
Luttrell (1955) - defined the Loculoascomycetes and established five orders (1973).
Systematics is controversial - one (von Arx & Müller 1975) to ten (Barr 1987) orders are recognized.
Group is probably not monophyletic.

5. LOCULOASCOMYCETES
Ascoma is an ascostroma and is called a pseudothecium when it resembles a perithecium.
Stroma develops before the ascogenous hyphae.
Centrum with or without pseudoparaphyses at maturity.
Asci are fissitunicate (bitunicate).

6. LOCULOASCOMYCETES Important plant pathogens Lichen associates
A few human and mammal pathogens
Endophytes
Decomposers of wood and other plant materials

7. FISSITUNICATE ASCUS
Consists of two clearly separate walls – an ectoacus & endoascus.
At the ultra-structural level each wall may consist of more than one layer.
The ectoascus is inelastic & breaks open to release the endoascus.
The inner wall is elastic and may extend to great lengths.
The ascospores are released through a pore at the apex of the endoascus.

8. FISSITUNICATE ASCUS

9. FISSITUNICATE ASCI
endoasci
endoasci

10. FISSITUNICATE ASCUS Relatively thin ectotunica and thicker endotunica
Complete separation of the ectotunica and endotunica during ascospore discharge
Ectotunica ruptures to release endotunica
Nasse apical surrounding an apical or ocular chamber
Banded pattern in endotunica often present
Ascospores forcibly shot from endotunica

11. HAMATHECIUM Periphysoids - short downward growing filaments
Paraphysoids - attached at both base and apex in young ascomata that become apothecioid at maturity
Pseudoparaphyses - downward growing or derived from elongation of cells occupying the centrum (cellular or trabeculate)

12. CELLULAR PSEUDOPARAPHYSES

15. MYRIANGIALES
Ascomata indeterminate in growth, wall consisting of pseudoparenchymatous tissue
Locules are uniascal; Elsinoë type centrum
Hamathecium absent
Asci globose or ovoid
Ascospores usually obovoid, aseptate or septate

16. MYRIANGIALES
Epiphytic over scale insects, insect secretions, resin glands, or biotrophic or saprobic on plants
Elsinoë fawcetii - citrus scab
Elsinoë ampelina - grape anthracnose
Elsinoë veneta - raspberry anthracnose

18. Grape Anthracnose

19. PLEOSPORALES
Ascomata perithecioid, cleistotheciod, or hysterothecioid)
Hamathecium of cellular pseudoparaphyses
Plant parasites or decomposers
More than one ascus per locule

20. MACROSPORA SCIRPICOLA AQUATIC PLEOSPORALES

21. PLEOSPORA HERBARUM

22. Venturia inaequalis
Apple scab

24. MELANOMMATALES
Ascomata may be perithecioid, cleistothecioid, or hysterothecioid
Pseudoparaphyses are trabeculate (thin, non-septate, surrounded by gel
Asci cylindric to clavate
Ascospores variable
Anamorphs are coelomycetous
Common on dead wood

25. MELANOMMATALES

26. MELANOMMATALES
pseudoparaphyses

27. MELANOMMATALES

28. DOTHIDEALES
Ascomata uniloculate or multiloculate; each locule containing more than one ascus
Asci usually arranged in fascicles
Hamathecium absent (no physes)

29. DOTHIDEALES Parasitic or saprobic on plants
Important plant pathogens: Mycosphaerella and Guignardia

30. DOTHIDEALES Mycosphaerella cercidicola - leaf spot of redbud
M. fragariae - leaf spot of strawberry
M. sentina - leaf spot of pear
M. mycopappi - leaf spot of maple
M. musicola - Sigatoka disease of bananas
Guignardia bidwellii - attacks grape

31. From Hanlin, 1990

32. MYCOSPHAERELLA FRAGARIAE