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• Smut fungi are a distinct group of fungi with a parasitic mycelial phase and a yeast-like phase in culture.
• Smut fungi are the second most important plant pathogens, behind the Uredinales.
• Grains represent 73% of the food consumed on earth.
• Effects of smut fungi include grain conversion to black teliospores, reduced vigor and yield, and smutted grain often with an off-taste and fishy odor (trimethylamine).
• Spores of smut fungi are explosive, long-lived, and allergenic.
• Corn smut, a type of smut fungi, is eaten in some parts of the world as food.
• Common names for smut fungi include "loose smut", "covered smut", "stinking bunt", and "corn smut".
• there are 7 orders recognized in the Ustilaginomycetes, the most economically important is the Ustilaginales.
• the Ustilaginaceae have septate metabasidium , the basidiospores are borne laterally.
• the Tilletiaceae have aseptate metabasidium and the basidiospores are borne apically on metabasidium
• smut fungi have intercalary teliospores or chlamydiospores
• smut fungi are facultative parasites of angiosperms (monocots and dicots). in nature they are functionally obligate parasites. homokaryon usually not infectious, dikaryon is infectious. most commonly found on inflorescence of monocots (grasses, onions, sedges, rushes but not ferns)
• smut fungi are all autoecious, meaning they complete their entire life cycle on one host.
• in smut fungi, none are macrocyclic and have three spore stages: teliospores, basidiospores and conidia
• smuts have neither basidiocarps or gametangia
• in smuts the basidiospores are not forcibly discharged
• smuts have no sterigmata and the basidiospores are sessile
• in smuts the conidia (sporidia) can be forcibly discharged (ballistospores)
• in smuts budding is a common type of reproductive mechanism
• in smuts clamps are present in some species
• in smuts the mating system is bipolar and multiallelic
• comparison of Rusts and Smuts: Teliospore

  • In rusts: Terminal
  • in smuts: Intercalary
• comparison of Rusts and Smuts: basidiospores

  • In rusts: ballistospores (sterigmata)
  • in smuts: Not forcibly discharged (no sterigmata)
• comparison of Rusts and Smuts: Gametangia

  • In rusts: Present (receptive hyphae and spermatia)
  • in smuts: Lacking
• comparison of Rusts and Smuts: Mycelium

  • In rusts: Intercellular and clamps are absent
  • in smuts: intra and inter cellular; clams are common
• comparison of Rusts and Smuts: hosts

  • In rusts: autoecious and heteroecious (localized) ferns, gymnosperms and angiosperms
  • in smuts: autoecious (systemic) angiosperms
• comparison of Rusts and Smuts: nutrition

  • In rusts: strict biotroph
  • in smuts: facultative biotrophs (yeast like in culture)
• Comparison of smut life and disease cycle Tilletia caries (Covered smuts) VS Ustilago nuda (Loose smuts): Teliospore

  • Tilletia caries (Covered smuts): site of karyogamy and meiosis
  • Ustilago nuda (Loose smuts): site of karyogamy and meiosis
• Comparison of smut life and disease cycle Tilletia caries (Covered smuts) VS Ustilago nuda (Loose smuts): Promycelium

  • Tilletia caries (Covered smuts): non-septate (metabasidium)
  • Ustilago nuda (Loose smuts): non-septate (metabasidium)
• Comparison of smut life and disease cycle Tilletia caries (Covered smuts) VS Ustilago nuda (Loose smuts): Basidiospores

  • Tilletia caries (Covered smuts): Terminally produced on metabasidium
  • Ustilago nuda (Loose smuts): Laterally produced on metabasidium
• Comparison of smut life and disease cycle Tilletia caries (Covered smuts) VS Ustilago nuda (Loose smuts): somatogamy

  • Tilletia caries (Covered smuts): between basidiospores "H-Cells" Primary sporidia
  • Ustilago nuda (Loose smuts): fusion tubes or clamps on metabasidium
• Comparison of smut life and disease cycle Tilletia caries (Covered smuts) VS Ustilago nuda (Loose smuts): Infection

  • Tilletia caries (Covered smuts): Dikaryotic sporidia infect seedlings
  • Ustilago nuda (Loose smuts): dikaryotic sporidia infect flower
• Comparison of smut life and disease cycle Tilletia caries (Covered smuts) VS Ustilago nuda (Loose smuts): colonization

  • Tilletia caries (Covered smuts): systemic infection; binucleate hyphae
  • Ustilago nuda (Loose smuts): systemic infection
• smut fungi have three types of infection:

  seedling

  • Tilletia spp

  flower

  • Ustilago spp

  general (meristematic tissue)

  • Ustilago maydis