High-throughput mutation detection underlying adaptive evolution of Escherichia coli-K12

Area of Science:

• Genomics
• Molecular Biology
• Biotechnology

Background:

• Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a powerful tool for detecting single base sequence variations.
• Automated, high-throughput mutation detection is crucial for microbial genomics and understanding adaptive evolution.

Purpose of the Study:

• To apply comparative sequencing using MALDI-TOF MS for automated, high-throughput mutation detection in microbial genomes.
• To identify DNA sequence changes in Escherichia coli K-12 MG1655 during laboratory adaptive evolution on glycerol.

Main Methods:

• Utilized MALDI-TOF MS for base-specific cleavage product analysis to detect DNA sequence variations.
• Applied a genome-scale in silico model of E. coli metabolism and growth to guide experiments.
• Resequenced 4.4% of the E. coli genome (1.54 Mb) in clones after 40 days of adaptive evolution.

Main Results:

• Detected ten mutations and three sequence deviations in 40 E. coli clones, representing the largest MALDI-TOF MS resequencing study to date.
• Identified mutations primarily within the glycerol kinase gene, with functional characterization revealing metabolic impact.
• Confirmed all sequence changes independently using genotyping and Sanger sequencing.

Conclusions:

• Comparative sequencing by base-specific cleavage and MALDI-TOF MS is an automated, fast, and highly accurate alternative to capillary sequencing for microbial genomics.
• This method enables efficient identification of mutations underlying adaptive laboratory evolution.
• MALDI-TOF MS-based comparative sequencing is a valuable tool for high-throughput mutation discovery in microbial populations.