Production of a high-efficiency TILLING population through polyploidization

Area of Science:

• Genetics
• Molecular Biology
• Plant Science

Background:

• Targeting Induced Local Lesions in Genomes (TILLING) is a valuable nontransgenic reverse genetics tool.
• TILLING efficiency relies on high mutation density, which varies by species and genetic background.
• Polyploid species often exhibit higher mutation densities compared to diploids.

Purpose of the Study:

• To investigate the effect of ploidy on mutation density for TILLING.
• To assess the feasibility of using autotetraploid Arabidopsis thaliana for enhanced TILLING.

Main Methods:

• Autotetraploid Arabidopsis thaliana (ecotype Columbia) was generated and mutagenized with ethylmethane sulfonate.
• Genomic DNA from M2 plants was pooled and sequenced using Illumina technology.
• Mutation detection was performed using an improved version of the CAMBa software.

Main Results:

• The tetraploid M1 plants produced sufficient seed for analysis, unlike the sterilized diploid.
• A high mutation density of approximately 25 mutations per 1.5-kb fragment was achieved.
• Overall mutation density reached 19.4 mutations Mb(-1), four times higher than in diploid Arabidopsis.

Conclusions:

• Genomic redundancy in polyploids tolerates higher mutation densities, significantly improving TILLING efficiency.
• Polyploidization enables the creation of small mutant populations (under 2,000 individuals) for generating comprehensive allelic series.
• This approach facilitates functional genomics studies, especially in species lacking extensive genetic resources.