Loculoascomycetes

1. Loculoascomycetes General Mycology 421/521 Lecture 9

2. Loculoascomycetes • Functionally bitunicate asci (=fissitunicate, Jack-in-the-Box type) • Extensible inner wall = endotunica • Inextensible outer wall = exotunica • Ascospores generally septate • Anamorph conidia often similar in septation • Unwalled locules in ascostroma (=ascolocular)—ascoma is initiated by formation of locule within stroma before formation of dikaryon

3. Elsinoe Pleospora Dothidea Images from http://www.tolweb.org/onlinecontributors/app?page=ImageGallery&service=external&sp=l29051&sp=0

4. Bitunicate (fissitunicate) ascus Apical chamber

5. Endotunica Exotunica

6. Ascostromatal types Hysteriothecium Pseudothecium Thyrothecium

7. From Blackwell et al. 2006. Mycologia 98: 834 Loculoascomycetes = Dothideomycetes

8. From Schoch et al. 2006. Mycologia 98: 1043

9. Importance • Endophytes • Animal Pathogens • Plant Pathogens • Cochliobolus heterostrophus Southern Corn Leaf Blight • Venturia inaequalis Apple Scab • Toxins (secondary metabolites)—host specific • T-toxins (Bipolaris maydis) • Alternaria toxins

10. Orders • Pleosporales • Hysteriales • Botryosphaeriales • Capnodiales • Dothideales • Myriangiales paraphysate Dothideomycetes Lack paraphyses or pseudoparaphyses—aparaphysate Dothideomycetes Tree of Life Page for Dothideomycetes

11. Order Pleosporales • Relatively large asci • Septate pseudoparaphyses • Well known taxa: • Cochliobolus heterostrophus (southern corn leaf blight) • Leptosphaeria maculans (black leg of rape seed) • Phaeosphaeria nodorum (stagonospora blotch of cereals) • Important anamorphs include Alternaria, Stemphylium, Drechslera, Ascochyta, Phoma, Pyrenochaeta

12. Pleospora From Hanlin, 1990

13. Stemphylium anamorph

14. Pyrenophora From Hanlin, 1990

15. Drechslera—conidia cylindrical, germinating from any cell; Pyrenophora teleomorphs

16. Exserohilum—conidia fusiform-cylindrical to obclavate with protuberant hilum; germination bipolar. Setosphaeria teleomorphs.

17. Bipolaris—conidia fusoid, hilum not protuberant; germination bipolar. Cochliobolus teleomorphs.

18. Curvularia photo by G. Barron

19. Helminthosporium • Once used for species now placed in Bipolaris, Drechslera, and Exserohilum • Restricted to species with obclavate conidia formed on straight conidiophores • Occurring on non-grass hosts

20. Alternaria Beaked dictyospores formed in acropetal chains; Lewia teleomorph

21. Sporormiella spp., common on dung. Ascospores segmented, each segment with a germ slit

23. Venturia • Globose pseudothecia formed in overwintered leaves • Unequally two-celled ascospores • Spilocaea anamorph with annellidic conidiogenous cells

24. Spilocea anamorph

25. Apple scab from APSnet, photo by J. Hartman

26. Order Botryosphaeriales • Includes Botryosphaeria and Guignardia—one-celled, hyaline to pale brown ascospores • Anamorphs pycnidial, phialidic • Diebacks, cankers, witches’ brooms and leaf blights http://www.crem.fct.unl.pt/botryosphaeria_site/

27. Orders of aparaphysate Dothideomycetes • Capnodiales • Dothideales • Myriangiales Lack paraphyses or pseudoparaphysesaparaphysate Tree of Life Page for Dothideomycetes

28. Order Capnodiales • Used in the traditional sense for sooty molds (leaf epiphytes associated with honeydew of insects) • Now includes families • Capnodiaceae—sooty molds • Davidiellaceae—Cladosporium anamorphs • Mycosphaerellaceae--Mycosphaerella • Piedraiaceae

29. Family Capnodiaceae • “Sooty Molds”—form dense, dark, tangled mixtures of hyphae on plant stems and leaves • Often associated with honeydew exudates of insects • Produce superficial ascocarps on well-developed subiculum

30. Sooty Molds From USDA Forest Service North Central Research Station

31. Scorias

32. Family Mycosphaerellaceae • Mycosphaerella sensu lato (now in 4 different genera) • Over 3000 species • > 30 different anamorphs recognized (Cercospora-like) • Small pseudothecia lacking pseudoparaphyses • Many important plant pathogens • Reference: Crous et al. 2007. Studies in Mycology 58:1-32.

33. Family Davidiellaceae • Cladosporium anamorphs have protuberant, thickened, darkened scars • Teleomorph Davidiella, similar to Mycosphaerella

34. Genus/Species:Piedraia hortae • Image Type:Macroscopic Morphology • Title: Black piedra • Disease(s): Piedra, black • Legend: Ascomycete fruiting body on a human hair. Family Piedraiaceae http://www.doctorfungus.org Piedraia hortae—causes black piedra; a specialized parasite on hair of primates in moist tropical areas

35. Order Dothideales • Dothidea and allied genera • Small ascomata and relatively few asci • Biotrophs, necrotrophs and saprobes on plant tissue • Black yeast anamorphs, including Aureobasidium, Hormonema Dothidea ascus by Sabine Huhndorf from TOL site

36. Aureobasidium pullulans (=Sydowia polyspora) • Holoblastic development; multiple conidia form from same cell • Conidiogenous cells usually not differentiated

37. Order Myriangiales • Globose asci produced singly in locules • Ascostroma with indeterminate growth • Representatives: • Myriangium—associated with plants, resins or scale insects on plants; tropical to subtropical • Elsinoë—parasites on plant leaves and stems; tropical to subtropical

38. Myriangium Elsinoë From Hanlin, 1990

39. From Schoch et al. 2006. Mycologia 98: 1043