1. How are basidiomycota characterized?
    • -by basidiospores (meiospores) formed on basidia(singular= basidium)the site of meiosis
    • - septate hyphae- some have clamp connections
    • - most of life cycle spent as dikaryon (n+n)
    • - no specialized gametangia- plasmogamy via fusion of hyphae
  2. What are In the order of Pucciniales?
    Rust fungi
  3. Describe rust fungi?
    • -Most species are heterothallic
    • -simple septal spores
    • -are obligate biotrophs
    • -have intercellular hyphae with haustoria
    • -have complex life cycles with up to five distinct spore types
    • -some species require two hosts for completion of life cycle = heteroecious
    • -some species complete life cycle on one host = autoecious
  4. WHat are the types of Pucciniales life cycles?
    • - macrocyclic - all five spore stages are present
    • - demicyclic - uredinial state (II) is absent
    • - microcyclic- aecial (I) and uredinial (II) state are absent
  5. What is stage 0 in rust fungi life cycle?
    • - results from infection by a haploid basidiospore
    • -haploid state (n)
    • - small pyncidial structures often in clusters
    • -develop in 4-6 days in herbaceous tissue up to 3-4 years in conifer wood
    • -receptive hyphae arise from upper walls and protrude through opening (ostiole)
    • -spermatia is a small one celled hyaline incapable of germination
    • -spermatia is a sweet sticky exudate which attracts insects
    • -dikaryotization occurs when spermatium fuses with receptive hyphae; nucleus moves down intercellular hyphae in host to aecial initials
  6. What is stage I in rust fungi life cycle?
    • - formed on same host as spermagonia
    • -dikaryotization in aecial initials ( n+n)
    • -aeciospores are one celled and form in chains usually pale orange in mass
    • -chains of aeciospores usually surrounded by aecial peridium
    • -aeciospores cannot infect the same host on which they are produced in heteroecious rusts
    • -infection by aeciospores results in uredinia (or telia in demicyclic rusts)
  7. What is stage II in rust fungi life cycle?
    • -repeating state: urediniospores are able to re-infect host on which they are formed and can cause secondary cycles of infection
    • -formed in uredinia on leaves stems fruits fronds sub-epidermal becoming erumpent
    • -urediniospores usually one celled echinulate (small spines) are round to Ovoid with germ piers formed on stalk
  8. What is stage III in rust fungi life cycle?
    • - teliospores form in the uredinium (if present)
    • -teliospores are site of karyogamy (n+n)
    • -teliospores germinate by formation of basidium and basidiospores
    • -teliospores have a dormancy requirement in most species
    • - teliospores provide basis for taxonomy of rust fungi
  9. What is stage IV in rust fungi life cycle?
    • -diploid nucleus migrates into developing basidium and undergo meiosis
    • -septa formed in response to meiotic divisions (=four celled basidium)
    • -each cell of basidium forms a sterigmata and basidiospores are forcibly discharged
    • -basidiospores germinate from germ tubes orient growth using physical cues from the plant surface
    • -differentiate into appressoria when in contact with stomata indirect penetration of wheat leaves
  10. Describe Ustilaginomycotina smuts
    • - mostly biotrophs
    • -have unique septa morphology
    • -parasitic dikaryotic phase and a saprotrophic haploid phase
  11. Describe teliospores
    • -formed singly or in spore balls are mostly globose pigmented with thick ornamented walls
    • -size are from 3.5-60 um in diameter
    • -resistant structures
  12. What are sorus?
    • -they are teliospores formed in sori
    • -composed of host and fungal tissue
    • -Formed in host ovaries stems leaves or roots depending on the smut taxon
Card Set
cards for plant pathology