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
What are In the order of Pucciniales?
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
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
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
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)
What is stage II in rust fungi life cycle?
: 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
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
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
Describe Ustilaginomycotina smuts
- mostly biotrophs
-have unique septa morphology
-parasitic dikaryotic phase and a saprotrophic haploid phase
-formed singly or in spore balls are mostly globose pigmented with thick ornamented walls
-size are from 3.5-60 um in diameter
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
cards for plant pathology