Comparison of the omtA genes encoding O-methyltransferases involved in aflatoxin biosynthesis from Aspergillus...

Area of Science:

• Mycology
• Molecular Biology
• Biochemistry

Background:

• Aflatoxins (AF) are toxic secondary metabolites produced by Aspergillus fungi.
• O-methyltransferase (OMT) is a key enzyme in the AF biosynthesis pathway.
• Understanding the omtA gene is vital for controlling AF contamination.

Purpose of the Study:

• To sequence and analyze the omtA gene in Aspergillus parasiticus (Ap) and Aspergillus flavus (Af).
• To compare the genomic and cDNA sequences of the omtA gene between these two fungal species.
• To identify conserved regions and structural features of the omtA gene.

Main Methods:

• Genomic DNA cloning and sequencing of the omtA gene from Ap strain SRRC 143 and Af strain CRA01-2B.
• Comparison of genomic DNA sequences with cDNA sequences.
• Sequence alignment and identity analysis.

Main Results:

• The omtA gene was successfully sequenced in both Ap and Af.
• Four introns, 52-60 bp in length, were identified in the omtA gene of both species.
• The S-adenosylmethionine-binding motif was located between the third and fourth introns.
• The coding sequences of omtA from Ap and Af showed over 97% identity.

Conclusions:

• The omtA gene structure, including intron number and location, is conserved between Aspergillus parasiticus and Aspergillus flavus.
• High sequence identity in the coding region suggests functional conservation of OMT in aflatoxin biosynthesis.
• These findings provide a basis for further research into OMT function and AF control strategies.