PENICILLIUM
(BLUE MOLD)

CLASSIFICATION OF PENICILLIUM (BLUE MOLD)​

Kingdom :- Mycota

Division :- Eumycota

Sub-division :- Ascomycotina

Class :- Plectomycetes

Order :- Eurotiales

Family :- Eurotiaceae

Genus :- Penicillium

The Penicillium fungus can easily be found or grown on citrus and other fruits and on foodstuff. It generally grows in association with Aspergillus, but since it is a weak saprophyte it is dominated by Aspergillus.

STUDY OF VEGETATIVE STRUCTURE

COMMENTS :-

  • The fungus is a saprophyte and is commonly found on citrus and other fruits, jellies and other foodstuffs. 
  • The mycelium is freely branched, septate and each cell is uni- or multinucleate. 
  • The mycelium may grow superficially on the surface of substratum or may penetrate deeply.
  • The hyphae are generally coloured due to pigments on the surface of hyphal walls.

Penicillium. Mycelium bearing conidiophore and chains of conidia.

STUDY OF CONIDIA​

COMMENTS :-

    • The conidia are the asexual spores borne on long, erect and branched conidiophores.
    • The branched conidiophore, with its conidia looks like a small ‘Penicillus’ (a brush in Latin).
    • Each conidiophore grows vertically from the mycelium and branches at its upper end. The ultimate branches are known as metulae. 
    • Each branch of conidiophore ends in bottleshaped sterigmata bearing a group of conidia arranged basipetally. 
    • The conidia are generally blue, sometimes green or -yellow and give characteristic colour to the colony.
    • The conidia are globose to ovoid in shape and appear as glass beads under the microscope.

Penicillium. A cleistothecium.

ASCOCARP, ASCI AND ASCOSPORES​

COMMENTS :– 

  • The fruiting body or ascocarp is called cleistothecium. It has a wall-peridium made of sterile hyphae which encloses many asci and paraphyses.
  • The globose or pear-shaped asci lie scattered inside the cleistothecium. 
  • Each ascus has eight uninucleate and wheelshaped ascospores.
  • The ascospores are ultimately released by the rupture of cleistothecium and after falling on a suitable medium germinate into new mycelia. 
  • The perfect stage i.e. cleistothecium is known as Eupenicillium, Teleromyces, Carpenteles.

Penicillium. A part of cleistothecium in cross section

IDENTIFICATION

  • Kingdom – Mycota
    1. Chlorophyll absent
    2. Reserve food glycogen
    3. Cell wall of fungal cellulose.
  • Division Eumycota
    1. A definite cell wall present.
  • Sub-division :- Ascomycotina
    1. Mycelium septate.
    2. Spores borne endogenously in the ascus.
    3. Spores in definite numbers, in multiples of two, usually eight.
  • Class :- Plectomycetes
    1. Ascocarp, a cleistothecium.
  • OrderEurotiales
    1. Cleistothecia sessile
  • Family Eurotiaceae
    1. Asci lie scattered, hymenium not formed.
    2. Peridium made of closely interwoven hyphae.
  • Genus Penicillium
    1. Branched, brush-like conidiophore.

REFERENCES

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