The document summarizes information about the fungi group Zygomycotina. It is divided into two classes: Zygomycetes and Trichomycetes. Zygomycetes are mostly terrestrial fungi that reproduce sexually through the fusion of opposite hyphae to form spores called zygospores. Rhizopus stolonifer is a common member. Trichomycetes are typically symbiotic fungi living in arthropod guts. The document also provides details about the fungi Mucor and Rhizopus, including their structures, life cycles, and reproduction methods.

1. Zygomycotina
Vaishali S.Patil
Professor, Department of Botany
Shri Shivaji College of Arts, Commerce & Science
Akola

2. •The fungi belonging to this group are generally terrestrial and
they produce zygospore (Gr. zygos — yoke; Spora — seed,
spore) after sexual reproduction.
•The thallus is normally haploid, consisting of coenocytic
mycelium and its cell wall contains chitin and chitosan.
•The mycelium contains cell organelles like other fungi,
except typical golgi bodies and centriole.
• Asexual reproduction takes place by aplanospores.
•Sexual reproduction takes place by gametangial copulation,
resulting in the formation of zygospore.

3. Subdivision Zygomycotina divided into two classes:
i. Zygomycetes-The Zygomycetes division of fungi includes mostly
terrestrial fungi. Because the hyphae have no cross walls between the
cells, they are said to be coenocytic. Sexual reproduction in these
organisms occurs when sexually opposite hyphae fuse and form spores
called zygospores.
A common member is the bread mold Rhizopus stolonifer. This fungus
forms a white or gray mycelium on bread. The sporangia containing the
asexual spores can be seen extending into the air. One species
of Rhizopus is used to ferment rice to make sake, and another species is
used in the production of cortisone.
ii. Trichomycetes-They are obligate symbiotic organisms that typically
live in the guts of arthropods. They are generally viewed as commensals,
having little effect on the host, but in stressful environments they might
confer an advantage to colonized hosts; in some cases they act as
pathogens. Most trichomycetes colonize freshwater and marine
arthropods, but some colonize terrestrial arthropods. Hosts are filter
feeders, detritus feeders, or aquatic grazers, but not predators or fluid

4. Mucor (“Black or Bread mould” mould)
Kingdom: Mycota
Division: Zygomycota
Sub-division: Zygomycotina
Class: Zygomycetes
Order: Mucorales
Family: Mucoraceae
Genus: Mucor
Characters-
•There are many species of Mucor (around 50) that are distributed
worldwide.
•It can cause diseases particularly called mucormycosis that might affect
the mucous membrane, lungs, eyes, skin etc.

5. •The hyphae are coenocytic, but septa may appear in the
mature hyphae. The cytoplasm of the hypha appears granular.
•It lives in a habitat like organic soil, bread, jam, jellies, a dead
decaying matter of fruits, vegetables and plants i.e.
“Saprophytic” and “Coprophilous” (grows in cow dung or
the dung of other herbivorous animals).
•The vegetative body of is “Eucarpic” ( Thallus is
differentiated into vegetative and reproductive structure)
•The major reserve food material is in the form of glycogen
and oil droplets.
•The cell is composed of mainly cellulose and chitin.

6. Structure-
•The mycelium is highly branched, multinucleate and it forms a fine
network of hyphae. It is filamentous, aseptate or coenocytic. Colony
is white to grey and turns to brown
•Sporangiophore is elongated, slightly narrow in shape.
•Sporangiophore swells up to form a dome-like structure called
“Columella.”
•Sporangium is the round and thick outer covering which carries
numerous spores inside it. It can be globose to spherical.
•Spores are the reproductive structures forms within the sporangium
which are simple, black, motile or non-motile, flattened and variable in
shape and size.

7. Reproduction:
1.Vegetative reproduction- It occurs by the fragmentation method,
where a vegetative cell breaks into several fragments during some
unfavourable conditions. After which, each fragment then develops into a
new vegetative body.
2.Asexual reproduction- It occurs through the asexual and non-motile
spores like:
a)Chlamydospores-A hard wall covers these spores, and it develops
inside the vegetative cell during unfavourable conditions. In
unfavourable conditions, mycelium becomes septate by the

8. accumulation of nuclei and cytoplasm in a certain portion and becomes
surrounded by a thick wall called chlamydospores. This spore then
detaches from the mycelium and remains dormant. On favourable
conditions, they form a germ tube.
b)Oidiospores-When a mycelium grows in a substrate (rich in sugar),
some small, thin-walled and pearl-like reproductive structures form that
detaches out of the vegetative cell as in budding of yeast. Then
oidospores remain dormant for some time and on favourable conditions,
it forms a germination tube to form a new vegetative body.

9. c)Sporangiospores- These are the spores that form within the cell or
sporangium and are non-motile.
From the hyphae, first sporangiophores arise singly that are erect in
position and unbranched. After maturation it develops a large
round sporangium and inner columella. Inside the wall of sporangium
many thin-walled, multinucleate spores called “Sporangiospores” are
developed. The sporangiospores then releases out of the sporangia after
the columnella swells up due to the pressure exerted on the sporangial
wall. As a result, cell lysis occurs. The spores remain dormant for some
time, and when they obtain suitable substratum, they germinate to a new
vegetative body through the germ tube.

11. Sexual reproduction-

12. First, the thallus of two opposite strains, i.e. one is (+), and other is (-),
comes in contact with each other.
When they come in contact, there develops a small outgrowth or
protuberance from both of the thalli.
After that, the outgrowth swells to form “Progametangium”.
Then septum develops between the progametangium, and the fusion of
progametangia occurs that results in the formation of gametes called
“Coenogametes”.
Then gametes of both the strains fuse to form a “Zygote”.
The zygote then enlarges in size and get surrounded by a thick-walled
structure called “Zygospore”.
Zygospore is dark black in colour, which gets covered by the two layers,
namely:
Outer layer: Also called Exosporium.
Inner layer: Also called Endosporium.
The zygospore remains dormant for some time and on favourable
conditions, promycelium develops out from the zygospore, forming a
new vegetative body.

14. Economic Importance –
•Some members of the Mucorales are commonly used to ferment foods.
•The fermentation of foods is nutritionally important because the fungi
contribute substantially to the nutritional value of the foods.
• It produce important industrial products such as lactic acid, amylases,
rennin and organic such as fumaric acid.
• Other species are used in industrial fermentations in the conversion of
starch into sugar.
• The preparation of Chinese cheese called sufu from soybeans with the
help of the mucor Actinomucor.
• Many diseases of fruits that occur during storage and transit are caused
by the Mucorales.
• Some species of Mucor attack stored grains.
• Some species of Mucorales are known to cause the fatal diseases called
Mucoromycosis in domesticated animals and man. This infects lungs,
brainand other organs, particularly in man.

15. Rhizopus-(The Bread Mould)
Kingdom-Fungi
Division- Zygomycota
Class- Zygomycetes
Order- Mucorales
Family- Mucoraceae
Genus- Rhizopus
It is a saprophytic and parasitic fungi, found in moist or damp
places,vegetables, fruits, bread, jellies, etc. The vegetative
structure is made up of coenocytic (multinucleated) and
branched hyphae.

16. •They are fast-growing fungi and have a cottony appearance
•The body consists of branched mycelium. The mycelium
is coenocytic and composed of three types of hyphae; stolon, rhizoids
and sporangiophores
Stolon is the internodal region, it is aerial, forms an arch and touches the
substratum forming nodal region
Rhizoids are formed where the stolon touches the substratum at nodes.
They are branched, anchor the mycelium to the substratum and absorb
food.
Sporangiophores are the aerial and
reproductive mycelia. They are branched
and consist of sporangiospores terminally.
The cell wall is made up of chitin. The
cytoplasm is multinucleated and consists
of other cell organelles such as mitochondria,
endoplasmic reticulum, Golgi bodies, vacuoles
and oil droplets.

17. Reproduction- By vegetative, asexual and sexual methods.
Vegetative reproduction is by fragmentation and each of the
fragments of a stolon develops separately making a complete
mycelium
Asexual reproduction is by the formation of chlamydospores
and sporangiospores.
Formation of Chlamydospores: Chlamydospores are formed
during unfavourable conditions. An intercalary segment of
mycelium develops due to the formation of septae and

18. Formation of Sporangiospores: Sporangiospores are formed terminally
in sporangia of aerial mycelium called sporangiophores. They are formed
under favourable conditions.It develop from the upper side of the
rhizoidal node.The apical part swells up forming sporangium, as nuclei
and cytoplasm move apically.The cytoplasm of sporangium differentiates
into the denser peripheral region with more nuclei and the central
columella region with fewer nuclei and more vacuoles.Sporangiospores
develop inside sporangium.
They are multinucleated and non-motile
The wall of sporangium ruptures after
maturation and sporangiospores come
out as a powdery mass.After getting
suitable condition and substratum,
each spore germinates into a new mycelium.
accumulation of protoplasm. It is thick-walled and detaches from the
mycelium once it dries. They remain dormant until the favourable
conditions return and then germinate to form a new mycelium

19. Sexual reproduction is by fusion of two compatible hyphae. The species
are heterothallic, i.e. having different mycelium for + and – mating
strains or homothallic.The compatible hyphae come together. In both the
mycelia, a small outgrowth develops. It is known as progametangia
Nuclei and cytoplasm move towards the apical region and progametangia
make contact.The apical region is separated from the rest of the hyphae
by septae formation. This is known as gametangia.Gametangia conjugate
to form a multinucleated structure.
Plasmogamy is followed by karyogamy and diploid (2n) zygote is
formed. It is known as zygospore. Rest of the unpaired nuclei
degenerate.
Zygospores enlarge and become thick-walled and resistant to adverse
environmental conditions. On getting favourable conditions, zygospores
germinate.
The inner wall of zygospore develops into promycelium forming germ
sporangiophore, with germ, sporangium formed apically.
Meiosis occurs and haploid meiospores are formed. They come out after
rupture of the germ sporangium wall and develop into new mycelia.

21. Economic Importance-
•They are commercially used to produce various chemicals and alcoholic
products.
•R. oryzae is used in the production of cortisone and lactic acid.
•R. oryzae is also used for biosorption of heavy metals in wastewater.
•R. stolonifer is used to produce lactic acid, fumaric acid and cortisone.
•R. delemar is used to produce biotin and fumaric acid.
•Tempeh, a traditional soybean fermented product of Asia, is prepared
using Rhizopus species.
•Many traditional alcoholic beverages, e.g. Parakari (cassava product), is
prepared using Rhizopus.