Genomic variation in the genus Beta based on 656 sequenced beet genomes

Area of Science:

• Genomics
• Plant genetics
• Crop science

Background:

• Cultivated beets (Beta vulgaris ssp. vulgaris), especially sugar beet, are vital sucrose sources.
• Wild beet species (genus Beta) are distributed across the Atlantic coast, Macaronesia, and the Mediterranean.
• Understanding beet genomes is crucial for identifying genes related to stress resistance.

Purpose of the Study:

• To characterize beet genomes through large-scale sequencing.
• To identify genetic variations and population structures within the Beta genus.
• To pinpoint genomic regions under artificial selection in sugar beet.

Main Methods:

• Analysis of short-read data from 656 sequenced beet genomes.
• Identification of 10 million variant positions against the RefBeet-1.2 reference genome.
• Application of variant-based clustering (PCA, genotype likelihoods, tree calculations, admixture analysis).

Main Results:

• Distinguished main species and subspecies groups based on shared genetic variation.
• Confirmed separation of sea beets (Beta vulgaris ssp. maritima) into Mediterranean and Atlantic subgroups.
• Identified 15 Mbp of variation-poor regions in sugar beet, enriched for genes in development, stress response, and metabolism.
• Detected evidence of interspecific hybridization.

Conclusions:

• The genomic resources generated are valuable for crop improvement and wild beet conservation.
• The study enhances understanding of beet genealogy, population structure, and dynamics.
• Provides a foundation for further research into the complex biology of beets and their wild relatives.