Fragmentation of Pooled PCR Products for Highly Multiplexed TILLING

Area of Science:

• Genomics
• Molecular Biology
• Plant Science

Background:

• Massively parallel sequencing advances enable routine recovery of genetic variants across biological disciplines.
• High sequence coverage is crucial for detecting single nucleotide variants and small indels, but whole-genome approaches are limited by genome size and sample number.
• Targeted sequencing via PCR offers an alternative, allowing increased sample size through multiplexing and pooling while maintaining adequate coverage.

Purpose of the Study:

• To optimize and demonstrate ultrasonication for simultaneous fragmentation of multiplexed PCR amplicons.
• To evaluate the suitability of this approach for high-throughput TILLING (Targeting Induced Local Lesions IN Genomes) with highly pooled samples.
• To assess sequencing performance, including read coverage and base quality, for complex sampling schemes.

Main Methods:

• Optimization of ultrasonication for fragmenting multiplexed PCR amplicons.
• Application of the method to TILLING of 4096 chemically mutagenized Hordeum vulgare (barley) DNAs.
• Three-dimensional DNA pooling and sequencing of 32 pooled PCR products.
• Evaluation of sequencing data for read coverage and base quality.

Main Results:

• Ultrasonication effectively fragmented multiplexed PCR amplicons for sequencing.
• The approach demonstrated suitability for high-throughput TILLING with highly pooled samples.
• Sequencing performance metrics (coverage, base quality) were adequate for mutation recovery.
• Previously identified induced mutations were successfully recovered, validating the method's efficacy.

Conclusions:

• Ultrasonication is an effective technique for simultaneous fragmentation of multiplexed PCR amplicons.
• This optimized method supports high-throughput TILLING and other applications involving complex pooled DNA samples.
• The approach facilitates large-scale genetic screening by enabling efficient processing of numerous samples.