Presentation on theme: "PYRENOMYCETES II IB – 371 LECTURE 23 November 13, 2003."— Presentation transcript:
PYRENOMYCETES II IB – 371 LECTURE 23 November 13, 2003
HYPOCREALES Ascomata perithecial, some cleistothecial Wall soft, fleshy, membranous, white or brightly colored. Ostiolar canal periphysate. Asci unitunicate, clavate to cylindrical, persistent.
HYPOCREALES Apical paraphyses present in early stages of ascomatal development. True paraphyses absent. Ascospores diverse in shape & color; 0, 1, 2, or more septate. Stroma, when present, soft to fleshy, bright colored. Conidial states are phialidic.
HYPOCREACEAE Stromatic or ascomata in a hyphal subiculum. Paraphyses originate in innermost centrum layers but grow downwards as apical paraphyses.
HYPOCREACEAE Asci cylindric or clavate with an apical thickening perforated by a narrow canal. Ascospores one or two celled. Anamorphs are phialidic.
HYPOCREA Cushion shaped stromata found on decaying wood, bark or leaves. Ascospores are one septate and break into part spores. Anamorphs include Trichoderma and Gliocladium.
HYPOMYCES Parasitic on mushrooms. Cottony hyphae covers the mushroom. Problem in the mushroom growing industry.
Hypomyces lactiflorum From R. Hanlin, 1990
NECTRIACEAE Ascomata pale to brightly colored (pink, red, blue, dark purple, rarely brown). Stromatic or not stromatic. Peridium of large pseudoparenchymatous cells. Asci cylindrical, oblong or inflated. Asci formed in a basal hymenium.
NECTRIACEAE Ascospores hyaline, two celled. Conidial states phialidic, eg., Fusarium, Cylindrocarpon.
NECTRIACEAE Nectria galligena - apple & pear canker Nectria cinnabarina - coral spot Gibberella zea - red ear rotof corn Gibberella fujkuroi - foolish disease of rice (GA)
CLAVACIPITALES One family - Clavacipitaceae. Bright or darkly pigmented stromata. Narrowly cylindrical asci with thickened domelike caps perforated by long pores. Paraphyses formed on the lateral walls of ascomata. Ascospores are thread-like, long and septate. Anamorphs are phialidic, eg., Hirsutella, Acremonium.
Claviceps purpurea - Ergot of Rye
Ergot Stroma with Perithecia
Claviceps purpurea life cycle Sclerotia fall to ground in fall and overwinter. Sclerotia germinate in spring to produce stromata with perithecia. Thread-like ascospores are wind-disseminated. Ascospores that land on susceptible flower germinate and grow into the ovary. Sphacelia anamorph develops in ‘honey dew’ formed on infected florets. Conidia are dispersed to uninfected flowers by rain or insects.
Claviceps purpurea Causes ergot of rye and other grasses Sclerotia formed in grass ovary composed of pseudoparenchymatous fungal tissue May contain high levels of 3 types of alkaloids: Secoergolenes Ergolines Lysergic acid derivatives
Ergotism Ergotism is a disease in animals (including humans): Vascular constriction that may lead to gangrene Hallucinations Ergotism involved in/responsible for: St. Anthony’s Fire (Middle Ages) Salem Witch Trials (1692) Modern outbreaks in France, Ethiopia, India
Cordyceps Infects insect larvae (e.g., caterpillars) or underground fungal fruiting bodies Club-like stromata emerge from host, perithecia embedded in apical region Threadlike ascospores break apart while in ascus Cordyceps militaris has medicinal properties and has a long history of use in Asia
Cordyceps—the claims “Cordyceps is a top quality Chinese energy tonic. It increases endurance and prevents allergies, depression, and colds and flu by enhancing adrenal and lung energy. Cordyceps is recommended for people who feel short of breath, achy, or depressed from overwork, pollution, and bad dietary habits.”
Balansia and Epichloë Grass and sedge endophytes Endophytes are fungi that cause symptomless infections in plant hosts Anamorph Neotyphodium grows intercellularly in plant host Seed transmitted (vertical transmission) if flowers are produced by infected plants Horizontally transmitted in species inhibiting flower production Beneficial to plant: Secondary metabolites (alkaloids) produced by endophyte protects plants from herbivores (“Ryegrass Staggers”) May confer drought resistance to infected plants
OPHIOSTOMATALES Ascomata usually perithecial. Paraphyses and periphyses absent. Globose to ovoid, evanescent asci. Asci formed at base or at base and along sides. Asci released into ascomal cavity. Sporothrix and Leptographium anamorphs.
OPHIOSTOMATALES Mostly saprobic wood. Associated with bark beetles.
Ophiostoma ulmi O. ulmi O. novo-ulmi present. Dutch elm disease - fungus produces a wilt toxin (cerato-ulmin) Introduced pathogen.
DIAPORTHALES Perithecial, often with long beaks. Clavate or clylindrical asci with apical apparatus and pore. Asci may separate from hymenium and lie free in perithecial cavity. Paraphyses & periphyses present. Ascospores hyaline to brown, one to several septate. Numerous plant pathogenic species.
CHESTNUT BLIGHT Cryphonectria parasitica
American chestnut trees at Poplar Cove, Joyce Kilmer Memorial Forest, NC Photo S.V. Streeter, January 15, 1910
American chestnut tree 23 inches dbh, 83 feet tall; Scotland, Connecticut, 1905
Fungus probably entered at broken branch stub on left of trunk; orange stromata have broken through the lenticels to the surface; concentric ridges of callose are tree's defense, which fails. Chestnut blight (Cryphonectria parasitica [Murr.] Barr) on American chestnut tree (Castanea dentata [Marsh] Borkh.)
Chestnut blight (Cryphonectria parasitica [Murr.] Barr) on American chestnut tree (Castanea dentata [Marsh] Borkh.)