High-frequency heterokaryon formation by Mucor racemosus

Area of Science:

• Mycology
• Fungal Genetics
• Cell Fusion

Background:

• Auxotrophic strains of Mucor racemosus lack specific metabolic pathways, requiring supplementation for growth.
• Heterokaryons, cells containing genetically distinct nuclei, can be formed through fungal protoplast fusion.
• Prototrophic organisms can synthesize all their essential organic compounds from simple inorganic materials.

Purpose of the Study:

• To develop a method for producing prototrophic heterokaryons from auxotrophic strains of Mucor racemosus.
• To optimize conditions for efficient fungal cell fusion and heterokaryon formation.

Main Methods:

• Auxotrophic Mucor racemosus strains were cultured and their germlings converted to spheroplasts.
• Spheroplasts were generated using commercial chitinase and purified Myxobacter AL-1 chitosanase.
• Fusion was induced by mixing spheroplasts in solutions containing polyethylene glycol (PEG) and calcium chloride (CaCl2).

Main Results:

• Prototrophic heterokaryons were successfully formed from the fusion of auxotrophic spheroplasts.
• Optimal fusion conditions yielded prototrophic heterokaryons at a frequency of approximately 5%.

Conclusions:

• The study demonstrates a viable method for generating prototrophic heterokaryons in Mucor racemosus.
• This technique provides a foundation for genetic manipulation and metabolic studies in Mucor racemosus.