Penicillium fungi

Penicillium is called blue or green mold. It is commonly seen rotting fruits and vegetables . It belongs to phylum Ascomycota . Here the classification structure and reproduction of fungi is discussed.

1. Penicillium Fungi SUMANGALA.C.H. LECTURER,UCM

2. Classification Phylum: Ascomycota Class : Eurotiomycetes Order : Eurotiales Family : Trichocomaceae Genus : Penicillium

3. Occurrence : Penicillum found in soil ,decaying vegetation, air and are common contaminants on various substances. Penicillium causes food spoilage, colonizes leather objects . They are saprophytes on decaying fruits and vegetables.

4. Structure They are commonly called the blue or green mold because they produce enormous quantities of greenish or bluish spores which give them their characteristic colours. Penicillium on PDA

5. Penicillium (name got because of brush like appearance ). On Lactophenol staining microscopic view of Penicillium : -conidiophore -metulae -sterigmata -conidia

6. The mycelium is multinucleated and septate long thread like structure known as hyphae . The hyphae is called conidiophore . At the apex of conidiophore are enlarged cells known as metulae . From the metulae phialides ( sterigmata ) arises. The conidia are produced in chains from the tip of sterigmata .

7. Reproduction and life cycle Reproduction in Penicillium is by 1. Vegetative 2. Asexual 3. Sexual method

8. 1.Vegetative reproduction is by fragmentation where hyphae breakup into small fragments. Each fragment then develops into full mycelium . 2. Asexual reproduction Asexual reproduction in Penicillium takes place by asexual spores called conidia . Conidia get detached from parent after maturation and get dispersed by the wind . When the spore gets attached to a suitable substrate they germinate by germ tube formation.

9. The nucleus divides mitotically multiple times and enter germ tube and gives rise to mature mycelium . Penicillium Conidia Germination

10. Sexual reproduction Sexual reproduction is by ascospores . Male sex organs are called Antheridia and female sex organs are known as ascogonia One of the cells of the vegetative mycelium develops into ascogonium . Ascogonium is elongated flask shaped and has single nucleus at beginning but as it matures the nucleus divides to form about 64 nuclei .

11. The developing antheridium branch coils around the ascogonium and at the tip it is separated by septa forming a unicellular antheridium having a single nucleus. After maturation antheridium comes in contact with ascogonium . At this region of contact , wall d issolve and the protoplast of both mingle with each other. The process is known as plasmogamy which takes place by gametangial contact. Dikaryotic phase is formed by septation of the ascogonium into binucleate cells .

12. The terminal dikaryotic cells swells up forming ascus mother cell. In this karyogamy occurs forming diploid nucleus . The young ascus enlarge and undergo two meiotic and one mitotic divisions to give a 8 haploid ascospores . Around the ascus many sterile hyphae grow and completely encircle it to form an ascocarp.

13. Mature ascocarp is called Cleisthothecium . Ascospores are released by the rupture of Ascocarp. When ascospores fall on suitable substratum they germinate to form new mycelium of Penicillium .

14. Economic importance Antibiotic Penicillin is obtained from Penicillium notatum . Penicillium species used in the production of cheese .example Penicillium roqueforti used in roqueforti cheese for colour, texture and distinctive odour and flavour . used in the production of citric acid ,gluconic acid etc. used in the production of enzymes like amylases ,proteases lipases etc.  

15. Economic loss: Penicillium species damage stored fruits by causing rot and decay. Example Penicillium digitatum and Penicillium expansum cause rot and decay of lemon, orange and other vegetables. Penicillium species damage leather goods and furniture too.