Researchers Describe Gene that Makes Large, Plump Tomatoes

In a study published in PLOS Genetics on August 17, 2017, Esther van der Knaap of the University of Georgia, Athens and colleagues describe Cell Size Regulator (CSR) gene, where mutation during the tomato domestication process allows farmers to grow big and plump juicy tomatoes. The CSR gene boosts fruit weight by increasing the size of individual cells in the pericarp, which is the fleshy part of the tomato.

Domesticated tomato varieties carry a mutation in the CSR genes that shortens the resulting protein in tomato cells, and that truncation likely affects its role in regulating cell differentiation and maturation in the fruit and vascular tissues. The variation originated in the cherry tomato, but now appears in all large cultivated tomato varieties.

The new study expands the previous research that identified the location of CSR gene at the bottom of chromosome 11 as only a small genetic contributor to tomato weight. Now with the cloning of the gene, the finding that most cultivated tomatoes carry the shortened version of the CSR gene suggests that humans selected this genetic variation extensively and that it was critical to the full domestication of tomato from its cherry tomato ancestors.

For more, read the paper in PLOS Genetics.