The identification of genetic regions involved in the selective breeding of tomatoes for agriculture is reported in a study published online this week at Nature Genetics. The results may lead to further improvement of the tomato crops in the future.
Generations of breeding tomatoes for consumption has led to larger and tastier tomatoes, but has also reduced their genetic diversity. This limits the ability of farmers to further improve tomato crops using standard breeding techniques. By understanding how and where humans have altered the tomato genome, through selective breeding and varietal selection, scientists can pinpoint genetic regions that can be improved by breeding with special varieties or using DNA editing technology.
Sanwen Huang and colleagues sequenced the genomes of 360 diverse tomato plants from around the world, including domesticated strains and wild species. They identified a group of tomatoes that are intermediate between wild and commercial processing tomatoes. The intermediate group has been domesticated, but has not undergone additional improvement for size and weight. Approximately 8% of the tomato genome was found to be involved in domestication and about 7% of the genome was selected for during the later improvement phase, though about one-fifth of these regions overlapped. Genes in these regions include one that is a possible domestication gene that responds to plant hormones in the flower bud and multiple “improvement” genes that control different aspects of plant size.