An optimal pooling strategy applied to high-throughput screening for rare marker-free transformants

Area of Science:

• Biotechnology
• Molecular Biology
• Genetics

Background:

• Marker-free transformation is crucial for developing genetically modified organisms, but identifying rare transformants poses a significant challenge.
• Traditional methods for screening transformants are often labor-intensive and inefficient, especially for rare events.

Purpose of the Study:

• To develop and validate an optimal pooling system, Accurate and Fast Target Screening (AFTS), for high-throughput identification of rare marker-free transformants.
• To improve the efficiency of detecting target genes and transgene expression compared to analyzing individual samples.

Main Methods:

• Developed the Accurate and Fast Target Screening (AFTS) pooling strategy by calculating optimal group sizes based on target proportions and worst-case scenarios.
• Applied AFTS to identify transgenes in a mixed population of transgenic and non-transgenic wheat lines using Polymerase Chain Reaction (PCR).
• Utilized SDS-PAGE of seed proteins to confirm transgene expression using the AFTS approach.

Main Results:

• The AFTS system identified rare targets 10- to 100-fold more efficiently than individual sample analysis.
• Successfully detected 10 positive transgenic wheat samples among 990 negative samples using only 92 PCR reactions.
• AFTS provided unambiguous positive or negative results for transgene identification and expression analysis.

Conclusions:

• The Accurate and Fast Target Screening (AFTS) system offers a highly efficient and cost-effective method for identifying rare marker-free transformants.
• This high-throughput screening approach significantly reduces the number of tests required, facilitating the advancement of marker-free transformation technologies.
• AFTS is a versatile tool applicable to both DNA-level transgene detection and protein-level expression analysis.