LAB PRACTICAL 4: Introduction to Fungi

INTRODUCTION

Fungi are heterotrophic microorganisms that are enzymatically capable of metabolizing a wide variety of organic substrates. It can be beneficial as well as detrimental on humans. Fungi in soil play a vital role in decomposing dead plant and animal tissues, thereby maintaining a fertile soil environment is prominent in ensuring the viability of beneficial fungi. Fungi are detrimental due to its ability to cause spoilage of foods by rots, mildews, and rust found on fruit, vegetables and grains. True fungi are divided into four groups of classes according to their sexual modes of reproduction. There are:

1.     Phylum: Zygomycota
        Class: Zygomyctes
        Reproductive spores are external and uncovered.
        Sexual spores: zygospores
        Asexual spores: sporangiospores.
 
2.     Phylum: Chytridiomycota
        Class: Chytridiomycetes
        Sexual spores: zygospores
        Asexual spores: zoospores
 
3.     Phylum: Basidiomycota
        Class: Hymenomycetes
        Sexual spores: basidiospores from basidium
 
4.     Phylum: Ascomycota
        Class: Deuteromycetes
        Reproduction by producing conidia

Fungi have the largest size of cell where the nucleus membrane contains mitochondria which differs it from bacteria. It also has a complex morphology and various structure. Most fungi can be cultured on media using the same inoculation technique as bacteria. However, there are some species that requires a special inoculation technique. The pure culture must be incubated at 25 ^oC – 30 ^oC for 2 or 3 weeks. Fungi that contain spore will be used as sample for identification under microscope by culture slide.

Commonly used fungi culture media is potato dextrose agar (PDA).  There are specific media used such as oatmeal agar which is suitable for stimulating the reproduction structure of low fungi. To avoid the any contaminations, the fungi culture media must be acidic because only fungi can adapt with the acidic environment. Addition of antibiotic in media can reduce the contamination in fungi culture.

OBJECTIVES

• To view the different shape of fungi under microscope and determine the reproduction mode of the fungi. 

PROCEDURE

Inoculation of fungi:

1. The PDA media is prepared in petri dish and the media is ensured to be completely solidified.
2. The tools are ensured to be sterilised (core 5mm) to avoid the contamination.
3. The cut of pure culture of fungi is placed in the centre of the media in the petri dish.
4. The culture is incubated at 25 - 30 ℃ for 2 to 3 weeks and observed the growth.

Identification and observation of fungi:

Observe directly on the petri dish by using microscopic with naked eye or under microscope ‘dissecting’.

Materials and apparatus:

Figure 1 shows the materials and apparatus used for preparing slides

to be viewed under microscope.

Figure 2 shows the pure culture of fungi.

Figure 3 shows the process of adding a drop of

lactophenol-cotton blue on the slide.

       i.       The slide is prepared by putting a drop of lactophenol-cotton blue or water on the slide.

Figure 4 shows the process of sterilizing inoculation loop.

Figure 5 shows the extraction of culture using loop.

    ii.    A small amount of fungi culture is taken by using a lope that has been sterilized and placed on the lactophenol-cotton blue or water drop.

Figure 6 shows the placement and spreading of culture on slide.

      iii.       The fungi culture is spread on the drop by using a needle.

Figure 7 shows the placement of cover slide over the culture.

      iv.       Next, the slide is slowly closed by glass cover.

       v.       The slide is observed under microscope by using all the magnifying glass and some oil has to be added to observe using the x100 magnifying power.

      vi.       The observation is taken by capturing a picture.

There are several prepared slides to be observed for identifying the morphology and the reproductive structure.

RESULTS AND DISCUSSION

1. Slide preparation

a)    Phytophthora palmivora

        Kingdom: Chromista

        Phylum: Oomycota

        Class: Oomycetes

        Causes bud rot disease

Figure 8 shows the microscopic view at x40 of Phytophthora palmivora.

b)     Rhizopus sp. 

        Kingdom: Fungi
        Phylum: Zygomycota
        Class: Zygomycetes
        Causes bread mould

Figure 9 shows the microscopic view at x40 of Rhizopus sp.

c)    Chaetomium sp.

        Kingdom: Fungi
        Phylum: Ascomycota
        Class: Pyrenomycetes
        Causes leaf spot disease (Jiang et al., 2018)
        Can be beneficial to plants by suppressing bacterial pathogen, enhance plant stress tolerance, etc

Figure 10 shows the microscopic view at x40 of Chaetomium sp.

d)    Aspergillus sp.

        Kingdom: Fungi
        Phylum: Ascomycota
        Class: Plectomycetes
        Causes black mould disease, black rot disease and more

Figure 11 shows the microscopic view at x40 of Aspergillus sp.

e)    Sclerotium sp.

        Kingdom: Fungi
        Phylum: Basidiomycota
        Class: Agaricomycetes
        Causes southern blight disease  

Figure 12 shows the microscopic view at x40 of Sclerotium sp.

2. Prepared slide observation

a)    Phytophthora sp.

        Phylum: Oomycota
        Class: Oomycetes

        -        Oospore (sexual reproduction)

Figure 13 shows the microscopic view at 40x of Phytophthora sp. oospore. 

Figure 14 shows the oospore diagram of Phytophthora sp. at x40.

  -        -            Sporangiospore and sporangium (asexual reproduction)

Figure 15 shows the microscopic view at 40x of Phytophthora sp. sporangium. 

Figure 16 shows the sporangium diagram of Phytophthora sp.

b)    Rhizopus sp. 

       Phylum: Zygomycota
       Class: Zygomycetes
  -        Zygospore (sexual reproduction)

Figure 17 shows the microscopic view at 40x of Rhizopus sp. zygospore. 

Figure 18 shows the zygospore diagram of Rhizopus sp.

        -        Sporangium (asexual reproduction)

Figure 19 shows the microscopic view at 40x of Rhizopus sp. sporangium. 

Figure 20 shows the sporangium diagram of Rhizopus sp.

c)    Erysiphe sp.

       Phylum: Ascomycota
       Class: Plectomycetes
 -        Kleistothecium (asexual reproduction)

Figure 21 shows the microscopic view at 40x of Erysiphe sp. ascus. 

 -        Oidium (asexual reproduction)

Figure 22 shows the microscopic view at 40x of Erysiphe sp. oidium. 

Figure 23 shows the diagram of Erysiphe sp. reproductions.

d)    Saccharomyces sp.

       Phylum: Ascomycota
 -        Budding (asexual reproduction)

Figure 24 shows the microscopic view at 40x of Saccharomyces sp. 

Figure 25 shows the diagram of Saccharomyces sp. budding cycle.

e)    Chaetomium sp.

       Phylum: Ascomycota

       -        Perithecium (sexual reproduction)

Figure 26 shows the microscopic view at 40x of Chaetomium sp. perithecium. 

Figure 27 shows the diagram of Chaetomium sp. perithecium at x10.

f)    Peziza sp.

       Phylum: Ascomycota

       -        Apothecium (sexual reproduction)

Figure 28 shows the microscopic view at 40x of Peziza sp. ascus. 

Figure 29 shows the microscopic view at 40x of Peziza sp. ascus layer at x4. 

Figure 30 shows the diagram of Peziza sp. ascus.

g)    Fusarium sp.

       Phylum: Ascomycota
 -        Macroconidia and microconidia 

Figure 31 shows the microscopic view at 40x of Fusarium sp. macroconidia and microconidia. 

Figure 32 shows the diagram of Fusarium sp. microconidia.

Figure 33 shows the diagram of Fusarium sp. macroconidia. 

h)    Penicillium sp.

      Phylum: Ascomycota

      Class: Plectomycetes

Figure 34 shows the microscopic view at 40x of Penicillium sp. conidium. 

Figure 35 shows the diagram of Penicillium sp. conidium. 

i)    Puccinia graminis 

      Phylum: Basidiomycota
      Wheat rust
      Stage 0 – picnia

Figure 36 shows the microscopic view at 40x of Puccinia graminis (stage 0). 

Figure 37 shows the diagram of Puccinia graminis (stage 0). 

-        Stage 1 – aescium & aesciospore 

Figure 38 shows the microscopic view at 40x of Puccinia graminis (stage 1). 

Figure 39 shows the diagram of Puccinia graminis (stage 1). 

-        Stage 2 – uredium & uredospore

Figure 40 shows the microscopic view at 40x of Puccinia graminis (stage 2). 

Figure 41 shows the diagram of Puccinia graminis (stage 2). 

-        Stage 3 – telium & teliospore

Figure 42 shows the microscopic view at 40x of Puccinia graminis (stage 3). 

Figure 43 shows the diagram of Puccinia graminis (stage 3). 

j)    Volvariella sp. 

        Phylum: Basidiomycota
        Edible mushroom

Figure 44 shows the Volvariella sp. in a jar. 

Figure 45 shows the diagram of Volvariella sp. 

k)    Rigidoporus lignosus

       Phylum: Basidiomycota
       White root disease

 

 

Figure 46 shows the diagram of Rigidoporus lignosus. 

l)    Puccinia maydis

       Phylum: Basidiomycota
       Corn rust

Figure 47 shows the microscopic view at 40x of Puccinia maydis. teliospore. 

Figure 48 shows the diagram of Puccinia maydis teliospore.

CONCLUSION

in conclusion, different phylum and class of fungi might have different shape, color, morphology as well as the reproduction mode, either asexual or sexual. Zygomycota sexual spore is called zygospore and asexual spore is sporangiospore. Ascomycota reproduces through conidia and different classes have different shape of ascus. Basidiomycota reproduces through basidiospores from basidium.