The document provides an overview of basidiomycetes, a phylum of fungi that includes mushrooms, important plant pathogens, and decomposers in ecosystems. It describes their structure, reproduction, and lifecycle, emphasizing the role of basidia and ballistospores in their reproduction. Significantly, it highlights the trophic relationships between basidiomycetes and plants, particularly through mycorrhizal associations.

2. Muhammad Zeeshan Nazar 01
Usman Ali 03

3. Among the basidiomycetes are not only the
mushrooms, toadstools, puffballs, jelly fungi, and
shelf fungi, but also many important plant
pathogens including rusts and smuts.
The third phylum of fungi, the basidiomycetes
has about 22,000 named species.
 The majority of edible fungi belong to the Phylum
Basidiomycota.

4. These mushroom-producing basidiomycetes are
sometimes referred to as "gill fungi" because of
the presence of gill-like structures on the underside
of the cap. The "gills" are actually compacted
hyphae on which the basidia are borne.

5. Many of the basidiomycota with the larger
fruitbodies (toadstools etc.) are common and
important agents of wood decay or decomposers of
leaf litter, animal dung, etc.
Basidiomycota are very important for the ecosystem
and for humans.
Decomposition
Ecosystem Relationship

6. Some also form important symbiotic
relationships, such as mycorrhizal
associations with the roots of a plant,
whereby the fungus receives carbohydrates
from the plant’s photosynthesis and the
plant gains the mycelium's very large
surface area to absorb water and mineral
nutrients from the soil.

8. The basidia, which are the reproductive
organs of these fungi, are often contained
within the familiar mushroom, commonly
seen in fields after rain, on the supermarket
shelves, and growing on your lawn.

9. Basidiomycota
are unicellular
or multicellular,
sexual or asexual,
and terrestrial or
aquatic.
The fungi in the Phylum Basidiomycota are
easily recognizable under a light microscope by
their club-shaped fruiting bodies called basidia
(singular, basidium), which are the swollen
terminal cell of a hypha.
Club shaped

10. Basidiospores
Basidiomycota are so variable that it is impossible
to identify any morphological characteristics that are
both unique to the group and constant in the group.
The most diagnostic feature is the production
of basidia which are the cells on which sexual spores
are produced, and from which the group takes its
name.

11. ֎ One of the most fascinating characteristics of
Basidiomycota is the production of ballistospores.
Ballistospores
A ballistospore/ballistoconida
is a spore that is discharged into
the air from the tips of
sterigmata in species of fungus.
Ballistospores may be sexual or
asexual.
Sterigma

12. Clamp connections
Not all Basidiomycetes produce these, but when a
fungus does it will always be a basidiomycete.
A clamp connection is a structure formed by
growing hyphal cells of certain fungi to ensure each cell,
or segment of hypha separated by septa receives a set of
different nuclei, which are obtained through mating of
hyphae.
It is used to create genetic variation within the hypha.

14. As a group, the basidiomycota
have some highly characteristic
features, which separate them
from other fungi. They are the
most evolutionarily advanced
fungi, and even their hyphae
have a dinstinctly "cellular"
composition.
Basidiomycetes are named for their characteristic
sexual reproductive structure, the basidium.

15. The lifecycle of basidiomycetes includes alternation of
generations . Spores are generally produced through
sexual reproduction, rather than asexual reproduction.

16. 2 Multicellular stages alternate
Sporophyte represents the diploid generation (2n).
 Produce spores by meiosis.
 A spore undergoes mitosis to become a
gametophyte.
Gametophyte represents haploid generation (n).
 Produce gametes.
 A sperm and egg fuse, forming a diploid zygote
that undergoes mitosis and become the sporophyte.
Alternation of generations ???

17. Typically haploid Basidiomycota mycelia
fuse via plasmogamy and then the compatible
nuclei migrate into each other's mycelia and
pair up with the resident nuclei.

18. In the basidium, nuclei of
two different mating strains
fuse (karyogamy), giving
rise to a diploid zygote that
then undergoes meiosis.
This is the dikaryotic stage
of the basidiomyces lifecyle
and it is the dominant stage.
Karyogamy
Generally in basidiomycetes,
Karyogamy occurs by clamp
connection.

19. The haploid nuclei migrate into basidiospores, which
germinate and generate monokaryotic hyphae. The
mycelium that results is called a primary mycelium.
Mycelia of different mating strains can combine and
produce a secondary mycelium that contains haploid
nuclei of two different mating strains.
Mycelia
Primary mycelium
Secondary mycelium
Hyphae

20. Eventually, the secondary mycelium generates a
basidiocarp, which is a fruiting body that protrudes
from the ground; this is what we think of as a
mushroom.
Fruiting body
The Basidiomycota is Holocarpic in which the
entire thallus/body is converted into a Fruiting body.
The basidiocarp
bears the developing
basidia on the gills
under its cap.

21. Plasmogamy:
Fusion between
+ and – mating
types results in
formation of a
dikaryotic mycelium.
Mitosis:
Under the right
environmental
condition, a
basidocarp forms. Gills
of the basidiocarp contain
cells called basidia.
Cell division:
Four
basidiospores
are formed.
Basidium with
four nuclei
( 1n)
Meiosis:
Foue haploid nuclei
are formed in the
basidium.
Germination:
Mycelia form. There are
two mating types (+ and -).
+ Mating type
– Mating type
Mycelia (1n)
Karyogamy:
Basisia form
diploid nuclei.
Zygote (n)
Dispersal and
germination
Basidiospores (n)
Basidia
Basidiocarp