What makes fruit pear-shaped?

Fruit-crop domestication has led to a flourishing of fruit shape variation, the molecular basis of which remains unexplained. In the Early Edition of Proceedings of the National Academy of Sciences, Jiping Liu and colleagues describe characterization of the OVATE gene previously associated with a major quantitative trait locus (QTL) controlling pear-shaped fruit development in tomatoes (PNAS, DOI/10.1073/pnas.162485999, September 16, 2002.).

Liu et al. cloned the OVATE gene and identified a premature stop codon associated with the ovate pear-shaped phenotype. Overexpression of OVATE affected plant growth, fruit shape and floral organ development. OVATE encodes a novel protein with a nuclear localization signal and a 70-residue carboxyl-terminal domain that is conserved in tomato, Arabidopsis and rice.

The authors suggest that OVATE might represent a new class of genes that regulate plant growth and fruit shape.