Massive crossover suppression by CRISPR-Cas-mediated plant chromosome engineering

Area of Science:

• Genetics
• Molecular Biology
• Plant Science

Background:

• Recent advancements allow engineering of entire chromosomes using CRISPR-Cas9 technology.
• Chromosome restructuring is a key strategy for manipulating genetic exchange in plant breeding.

Purpose of the Study:

• To investigate the suppression of meiotic recombination through chromosome restructuring.
• To engineer a heritable chromosomal inversion and analyze its impact on genetic exchange.

Main Methods:

• Utilized CRISPR-Cas9 to induce a large, heritable inversion (>17 Mb) encompassing the centromere of Arabidopsis chromosome 2.
• Performed single-nucleotide polymorphism (SNP) marker analysis on offspring from crosses between engineered and wild-type ecotypes.

Main Results:

• Successfully induced a heritable inversion covering most of chromosome 2, with only telomeric ends retaining original orientation.
• Observed a significant reduction in meiotic crossovers within the inverted region.
• Detected a shift of crossovers towards the telomeric ends, with limited exchange within the inversion arising from double crossovers.

Conclusions:

• Chromosome restructuring effectively suppresses meiotic recombination across large chromosomal segments.
• Heritable genetic exchange can occur via interstitial chromosome pairing but is restricted in producing viable progeny.
• This technique offers novel avenues for manipulating genetic exchange in plant breeding programs.