Distribution of Genes Controlling Fruit Shape in the Tomato Germplasm and the Relationship to Fruit Shape Diversity

Cultivated tomatoes have different shapes and sizes. Through cloning, it was discovered that SUN and OVATE control elongated shape whereas FASCIATED (FAS) and LOCULE NUMBER (LC) control fruit locule number and flat shape. Ohio State University scientist Esther van der Knaap and colleagues investigated the distribution of the fruit shape alleles in the tomato germplasm and evaluated their role in morphology using different tomato varieties. Fruits were visually classified into eight shape categories with the aid of Tomato Analyzer software.

The findings showed that the allele distribution of SUN, OVATE, LC, and FAS was significantly associated with fruit shape classification. Through model-based clustering, it was found that selection for fruit shape genes was critical to subpopulation differentiation within cultivated tomato. Results suggest that LC, FAS, and SUN mutations arose in the same ancestral population while the OVATE mutation occurred in a different lineage. Moreover, LC, OVATE, and FAS mutations may have arisen before domestication or early during the selection of cultivated tomato whereas the SUN mutation appeared to be a postdomestication occurrence arising in Europe.

The full paper is available for subscribers of Plant Physiology Journal at http://www.plantphysiol.org/content/156/1/275.full.pdf+html.