Prescott, Harley, and Klein’s Microbiology 7th edition

1. Present By : Jinal Mehta
T.Y.BSC (microbiology)

3. 1. Basidiomycota 2. Ascomycota 3. glomeromycota
4. zygomycota 5. chitridiomycota 6. microsporidia

4.  Kingdom : Fungi
 Phylum:Zygomycota(“Pin”OR “Sugar”mold)
 Class : Zygomycetes(Phycomycetes)
 Order : Mucorales
 Family : Mucoraceae
 Genus : Rhizopus

5. ZYGOMYCOTA
 The name ZYGOMYCOAT refers to the
ZYGOSPORANGIA characteristic during
sexual reproduction .
 ZYGO = Joining ( It referring to the
FUSION of TWO HYPHAL STRANDS which
produces these SPORES. )
 MYCOTA = Suffix ( It referring to a division
of FUNGI. )

6.  WHY IT IS KNOWN AS “PINMOLD”
• Many Members of the ZYGOMYCOTA produce unbranched
sporangiophores with the sporangium for a ‘HEAD’ , A Structure that
superficially resembles a pin ; hence the common name of
ZYGOMYCOTA is “PIN MOLD” .
 WHY IT IS KNOWN AS “SUGARMOLD”
• Many Species commonly cause
economically destructive rotes of
fruits in storage.
• These fruits include STRAWBEERY ,
SWEETPOTATO are high in simple
sugars such as GLUCOSE .
• So It is also Known As “SUGAR -
MOLD” .

7. GENUS : RHIZOPUS
 The name Rhizopus was first named by “EHRENB” in 1820.
 There are around 8-10 known species of Rhizopus .
 They are Saprophytic OR Parasitic .
1. Saprophytic : Grow on Decaying Organic Matter .
2. Parasitic : cause disease on Living Organism .

8. STRUCTURE OF RHIZOPUS

9.  MYCELIUM :
It is Coenocytic , Tubular ,
Multinucleated , Vacuolated & Consist of
Cytoplasmic Materials Like Golgi Body ,
Mitochondrial ETC .
 The reserve food material is in the form
of Glycogen & oil droplets .
 A cell-wall of THULLUS is non-cellulose
& made of chitin .
 HYPHAE OF RHIZOPUS :
It differentiates into THREE distinctive parts .
 Namely “STOLON” , “RHIZOIDS” , “SPORANGIOPHORES” .
 For the growth of Rhizopus , the most important factor is
MOISTURE or WATER availability .

10. 1) RHIZOIDS :
It is NODAL REGION which forms when the stolon touches the surface
of the substratum.
 Rhizoid is the much-branched structure that forms
under the substratum.
 Its main function is to INVADE all the NUTRIENTS from the substratum.
2) STOLON :
It is the INTERMODAL REGION which also refers to runner.
 A stolon is the AERIAL HYPHAE which grow horizontally & is found
attached to the substratum.
 It is aseptate branched & lacks cross walls.
3) SPORANGIOPHORES :
It is REPRODUCTIVE hyphae.
 It grow VERTICALLY from the stolon.
 Sporangiophores are unbranched , elongated , columellate & give rise
to the reproductive structures refers to SPORANGIOSPORES.

11.  CELL-WALL :
The cell-wall of hyphae is
composed of CHITIN CHITOSAN ,
LIPID , PROTEINS etc.
 COLUMELLA :
It arises from the Sporangiophore
which is generally dome or Umbrella-
shape .
 Surface of Columella can be smooth or rough.
 Main function is absorption of the water.
 SPORANGIUM :
It connects with the columella & long sporangiophore.
 Shape of Sporangium is spherical or Globose.
 It carries the reproductive structure refers as Sporangiospore.

12. REPRODUCTION IN RHIZOPUS
 It Reproduces by Vegetative , Asexual &
Sexual methods.
VEGETATIVE REPRODUCTION
• Some time the thallus of the Rhizopus breaks
accidentally or some other factors into few
fragments where each fragment give rise to a new
thallus on favorable condition.

13. OVERVIEW ON RHIZOPUS REPRODUCTION

14. ASEXUAL REPRODUCTION

15. ASEXUAL REPRODUTION STEPS
1. The vegetative hypha grows
to form SPORANGIOPHORE
that is long & slender.
2. Then sporangiophore
develops & enlarge at the
apical region to form
COLUMELLA which is
variable shape & size.

16. 3. The columella give rise to the large , round SPORANGIUM
by pushing cytoplasmic material to the peripheral wall.
4. After that , differentiation of sporangium & columella ,
SPORE SAC is present which carries the
SPORANGIOSPORES. The structure of sporangiospores is
oval , unicellular , multicellular & non-motile.
5. These Sporangiospores multiply their number in the spore
sac & in extreme conditions , it ruptures the sporangial wall
& releases out of the wall.
6. In the environment , the sporangiospores remain in a
dormant state or in a resting state.
7. When favourable conditions return , these sporangiospores
form GERM TUBE & undergo GERMINATION to form a
VEGETATIVE HYPHAE.

17. SEXUAL REPRODUCTION

18.  Sexual Reproduction Requires Compatible Strain Of
Opposite Mating Types Like + & – . ( They are not
Morphologically distinguishable as Male OR Female. )
1) First + & - Thallus Conjugated with
Each Other , So Rhizopus is Also Known
As “Conjugated Fungi”.
2) Two Mating Strain Close each And
Produce a Different Harmon , Called a
PHEROMONE That Causes their Hyphae
That Known as PROGAMETANGIA .This
Mature into GAMETANGIA .
3) After Fusion of Gametangia the Nuclei of the Two
Gametes Fuse forming a ZYGOTE.

19. 4) The Zygote develops a THICK ,
ROUGH , BLACK COAT & become
a dormant ZYGOSPORE.
5) Meiosis Often Occurs at the time Of
germination.
6) The Zygospores Then Splits open &
Produces a Hyphae that bears an ASEXUAL
SPORANGIUM to begin the cycle Again.

20. 1) Rhizopus stolonifer :
• R. stolonifer first discovered by
Christian Gottfried in 1818 as
R. nigricans .
• The name change by J. P.
vuillemin in 1902 as R. stolonifer.
• R. stolonifer is a threadlike mold.
• Common name of R. stolonifer is
bread mold .
• It is depend on sugar OR starch
for its source of carbon substances
for food.
• It use food matter , generally breads or soft fruits , like
grapes or strawberry as a food source for growth , nutrition
& reproduction .

21. 2) Rhizopus oryzae :
• R. oryzae was discovered by Frist
went & Handrik geerligs in 1895.
• It found in various soils across the
world .
• In east asia it is common in
peanuts.
• It is present in maize , pistachios , wheat , barley ,
potatoes , & various tropical food
• It is also cause food poisone.