Transformation of Aspergillus nidulans by using a trpC plasmid

Area of Science:

• Molecular Biology
• Fungal Genetics
• Biotechnology

Background:

• The trifunctional trpC gene is essential for tryptophan biosynthesis in Aspergillus nidulans.
• Development of efficient gene transfer systems is crucial for fungal genetic studies.

Purpose of the Study:

• To construct and characterize a chimeric plasmid for the expression of the Aspergillus nidulans trpC gene in Escherichia coli and A. nidulans.
• To evaluate the efficiency of the constructed plasmid in transforming A. nidulans and integrating into its genome.

Main Methods:

• Construction of a chimeric plasmid (pHY201) containing the A. nidulans trpC gene.
• Transformation of Escherichia coli and A. nidulans trpC- strains with pHY201.
• Assessment of plasmid replication, complementation of auxotrophic mutants, and DNA integration using Southern blot analysis.

Main Results:

• The plasmid pHY201 replicates in E. coli and confers ampicillin and chloramphenicol resistance.
• pHY201 successfully complemented A. nidulans trpC mutants, restoring tryptophan prototrophy.
• High-frequency stable transformation of A. nidulans (greater than 20 transformants/µg DNA) was achieved.
• Southern blot analysis confirmed chromosomal integration of pHY201 in most transformants, often at the trpC locus.
• The plasmid was recoverable from A. nidulans transformants, indicating potential for further manipulation.

Conclusions:

• The chimeric plasmid pHY201 is a functional and effective tool for gene transfer and manipulation in Aspergillus nidulans.
• The study demonstrates successful complementation and chromosomal integration of the A. nidulans trpC gene using the developed plasmid system.
• This work provides a foundation for further genetic studies and metabolic engineering in filamentous fungi.